Config language WIP

19 files changed, 3399 insertions, 698 deletions

diff --git a/Tests/MODELS2020-CaseStudies/case.study.familyTree.run/bin/queries/.FamilyTreeConstraints.java._trace b/Tests/MODELS2020-CaseStudies/case.study.familyTree.run/bin/queries/.FamilyTreeConstraints.java._trace
index 364eae66..b000501e 100644
--- a/Tests/MODELS2020-CaseStudies/case.study.familyTree.run/bin/queries/.FamilyTreeConstraints.java._trace
+++ b/Tests/MODELS2020-CaseStudies/case.study.familyTree.run/bin/queries/.FamilyTreeConstraints.java._trace
diff --git a/Tests/MODELS2020-CaseStudies/case.study.familyTree.run/bin/queries/.MemberIsItsOwnParent.java._trace b/Tests/MODELS2020-CaseStudies/case.study.familyTree.run/bin/queries/.MemberIsItsOwnParent.java._trace
index 1b0dca98..aaf4d0c2 100644
--- a/Tests/MODELS2020-CaseStudies/case.study.familyTree.run/bin/queries/.MemberIsItsOwnParent.java._trace
+++ b/Tests/MODELS2020-CaseStudies/case.study.familyTree.run/bin/queries/.MemberIsItsOwnParent.java._trace
diff --git a/Tests/MODELS2020-CaseStudies/case.study.familyTree.run/bin/queries/.gitignore b/Tests/MODELS2020-CaseStudies/case.study.familyTree.run/bin/queries/.gitignore
index 3be531f5..3b9ccef7 100644
--- a/Tests/MODELS2020-CaseStudies/case.study.familyTree.run/bin/queries/.gitignore
+++ b/Tests/MODELS2020-CaseStudies/case.study.familyTree.run/bin/queries/.gitignore
@@ -6,3 +6,4 @@
 /.MemberHasNoParent.java._trace
 /.MemberHasParent.java._trace
 /.TwoMembersHaveNoParent.java._trace
+/.NegativeAge.java._trace
diff --git a/Tests/MODELS2020-CaseStudies/case.study.familyTree.run/bin/queries/familyTreeConstraints.vql b/Tests/MODELS2020-CaseStudies/case.study.familyTree.run/bin/queries/familyTreeConstraints.vql
index e7b44f0b..fdbac640 100644
--- a/Tests/MODELS2020-CaseStudies/case.study.familyTree.run/bin/queries/familyTreeConstraints.vql
+++ b/Tests/MODELS2020-CaseStudies/case.study.familyTree.run/bin/queries/familyTreeConstraints.vql
@@ -9,25 +9,31 @@ pattern memberIsItsOwnParent(m: Member) = {
         m == p;

 }

 

-//@Constraint(message="twoMembersHaveNoParent", severity="error", key={m1, m2})

-//pattern twoMembersHaveNoParent(m1:Member, m2:Member) = {

-//      neg find memberHasParent(m1);

-//      neg find memberHasParent(m2);

-//      m1 != m2;

-//}

-//

-//pattern memberHasParent(m: Member) = {

-//      Member.parents(m, _);

-//}

-//

-//@Constraint(message="parentTooYoung", severity="error", key={m, p})

-//pattern parentTooYoung(m: Member, p: Member) = {

-//      FamilyTree.members(_, m);

-//      Member.parents(m, p);

-//      Member.age(m, mAge);

-//      Member.age(p, pAge);

-//      check (mAge <= (pAge + 12));

-//}

+@Constraint(message="twoMembersHaveNoParent", severity="error", key={m1, m2})

+pattern twoMembersHaveNoParent(m1:Member, m2:Member) = {

+        neg find memberHasParent(m1);

+        neg find memberHasParent(m2);

+        m1 != m2;

+}

+

+pattern memberHasParent(m: Member) = {

+        Member.parents(m, _);

+}

+

+@Constraint(message="negativeAge", severity="error",key={m})

+pattern negativeAge(m: Member) {

+        Member.age(m,mage);

+        check(mage<0);

+}

+

+@Constraint(message="parentTooYoung", severity="error", key={c, p})

+pattern parentTooYoung(c: Member, p: Member) = {

+        FamilyTree.members(_, c);

+        Member.parents(c, p);

+        Member.age(c, cAge);

+        Member.age(p, pAge);

+        check (pAge <= (cAge + 12));

+}

 

 

 

diff --git a/Tests/MODELS2020-CaseStudies/case.study.familyTree.run/plugin.xml b/Tests/MODELS2020-CaseStudies/case.study.familyTree.run/plugin.xml
index b32b0215..4297ec89 100644
--- a/Tests/MODELS2020-CaseStudies/case.study.familyTree.run/plugin.xml
+++ b/Tests/MODELS2020-CaseStudies/case.study.familyTree.run/plugin.xml
@@ -1,7 +1,11 @@
-<?xml version="1.0" encoding="UTF-8"?><plugin>

-  <extension id="queries.FamilyTreeConstraints" point="org.eclipse.viatra.query.runtime.queryspecification">

-    <group group="org.eclipse.viatra.query.runtime.extensibility.SingletonExtensionFactory:queries.FamilyTreeConstraints" id="queries.FamilyTreeConstraints">

-      <query-specification fqn="queries.memberIsItsOwnParent"/>

-    </group>

-  </extension>

-</plugin>

+<?xml version="1.0" encoding="UTF-8"?><plugin>
+  <extension id="queries.FamilyTreeConstraints" point="org.eclipse.viatra.query.runtime.queryspecification">
+    <group group="org.eclipse.viatra.query.runtime.extensibility.SingletonExtensionFactory:queries.FamilyTreeConstraints" id="queries.FamilyTreeConstraints">
+      <query-specification fqn="queries.memberIsItsOwnParent"/>
+      <query-specification fqn="queries.twoMembersHaveNoParent"/>
+      <query-specification fqn="queries.memberHasParent"/>
+      <query-specification fqn="queries.negativeAge"/>
+      <query-specification fqn="queries.parentTooYoung"/>
+    </group>
+  </extension>
+</plugin>
diff --git a/Tests/MODELS2020-CaseStudies/case.study.familyTree.run/src-gen/queries/.FamilyTreeConstraints.java._trace b/Tests/MODELS2020-CaseStudies/case.study.familyTree.run/src-gen/queries/.FamilyTreeConstraints.java._trace
index 364eae66..b000501e 100644
--- a/Tests/MODELS2020-CaseStudies/case.study.familyTree.run/src-gen/queries/.FamilyTreeConstraints.java._trace
+++ b/Tests/MODELS2020-CaseStudies/case.study.familyTree.run/src-gen/queries/.FamilyTreeConstraints.java._trace
diff --git a/Tests/MODELS2020-CaseStudies/case.study.familyTree.run/src-gen/queries/.MemberIsItsOwnParent.java._trace b/Tests/MODELS2020-CaseStudies/case.study.familyTree.run/src-gen/queries/.MemberIsItsOwnParent.java._trace
index 1b0dca98..aaf4d0c2 100644
--- a/Tests/MODELS2020-CaseStudies/case.study.familyTree.run/src-gen/queries/.MemberIsItsOwnParent.java._trace
+++ b/Tests/MODELS2020-CaseStudies/case.study.familyTree.run/src-gen/queries/.MemberIsItsOwnParent.java._trace
diff --git a/Tests/MODELS2020-CaseStudies/case.study.familyTree.run/src-gen/queries/.gitignore b/Tests/MODELS2020-CaseStudies/case.study.familyTree.run/src-gen/queries/.gitignore
index 3be531f5..3b9ccef7 100644
--- a/Tests/MODELS2020-CaseStudies/case.study.familyTree.run/src-gen/queries/.gitignore
+++ b/Tests/MODELS2020-CaseStudies/case.study.familyTree.run/src-gen/queries/.gitignore
@@ -6,3 +6,4 @@
 /.MemberHasNoParent.java._trace
 /.MemberHasParent.java._trace
 /.TwoMembersHaveNoParent.java._trace
+/.NegativeAge.java._trace
diff --git a/Tests/MODELS2020-CaseStudies/case.study.familyTree.run/src-gen/queries/FamilyTreeConstraints.java b/Tests/MODELS2020-CaseStudies/case.study.familyTree.run/src-gen/queries/FamilyTreeConstraints.java
index a5c375c6..1d991140 100644
--- a/Tests/MODELS2020-CaseStudies/case.study.familyTree.run/src-gen/queries/FamilyTreeConstraints.java
+++ b/Tests/MODELS2020-CaseStudies/case.study.familyTree.run/src-gen/queries/FamilyTreeConstraints.java
@@ -1,53 +1,97 @@
-/**

- * Generated from platform:/resource/case.study.familyTree.run/src/queries/familyTreeConstraints.vql

- */

-package queries;

-

-import org.eclipse.viatra.query.runtime.api.ViatraQueryEngine;

-import org.eclipse.viatra.query.runtime.api.impl.BaseGeneratedPatternGroup;

-import queries.MemberIsItsOwnParent;

-

-/**

- * A pattern group formed of all public patterns defined in familyTreeConstraints.vql.

- * 

- * <p>Use the static instance as any {@link interface org.eclipse.viatra.query.runtime.api.IQueryGroup}, to conveniently prepare

- * a VIATRA Query engine for matching all patterns originally defined in file familyTreeConstraints.vql,

- * in order to achieve better performance than one-by-one on-demand matcher initialization.

- * 

- * <p> From package queries, the group contains the definition of the following patterns: <ul>

- * <li>memberIsItsOwnParent</li>

- * </ul>

- * 

- * @see IQueryGroup

- * 

- */

-@SuppressWarnings("all")

-public final class FamilyTreeConstraints extends BaseGeneratedPatternGroup {

-  /**

-   * Access the pattern group.

-   * 

-   * @return the singleton instance of the group

-   * @throws ViatraQueryRuntimeException if there was an error loading the generated code of pattern specifications

-   * 

-   */

-  public static FamilyTreeConstraints instance() {

-    if (INSTANCE == null) {

-        INSTANCE = new FamilyTreeConstraints();

-    }

-    return INSTANCE;

-  }

-  

-  private static FamilyTreeConstraints INSTANCE;

-  

-  private FamilyTreeConstraints() {

-    querySpecifications.add(MemberIsItsOwnParent.instance());

-  }

-  

-  public MemberIsItsOwnParent getMemberIsItsOwnParent() {

-    return MemberIsItsOwnParent.instance();

-  }

-  

-  public MemberIsItsOwnParent.Matcher getMemberIsItsOwnParent(final ViatraQueryEngine engine) {

-    return MemberIsItsOwnParent.Matcher.on(engine);

-  }

-}

+/**
+ * Generated from platform:/resource/case.study.familyTree.run/src/queries/familyTreeConstraints.vql
+ */
+package queries;
+
+import org.eclipse.viatra.query.runtime.api.ViatraQueryEngine;
+import org.eclipse.viatra.query.runtime.api.impl.BaseGeneratedPatternGroup;
+import queries.MemberHasParent;
+import queries.MemberIsItsOwnParent;
+import queries.NegativeAge;
+import queries.ParentTooYoung;
+import queries.TwoMembersHaveNoParent;
+
+/**
+ * A pattern group formed of all public patterns defined in familyTreeConstraints.vql.
+ * 
+ * <p>Use the static instance as any {@link interface org.eclipse.viatra.query.runtime.api.IQueryGroup}, to conveniently prepare
+ * a VIATRA Query engine for matching all patterns originally defined in file familyTreeConstraints.vql,
+ * in order to achieve better performance than one-by-one on-demand matcher initialization.
+ * 
+ * <p> From package queries, the group contains the definition of the following patterns: <ul>
+ * <li>memberIsItsOwnParent</li>
+ * <li>twoMembersHaveNoParent</li>
+ * <li>memberHasParent</li>
+ * <li>negativeAge</li>
+ * <li>parentTooYoung</li>
+ * </ul>
+ * 
+ * @see IQueryGroup
+ * 
+ */
+@SuppressWarnings("all")
+public final class FamilyTreeConstraints extends BaseGeneratedPatternGroup {
+  /**
+   * Access the pattern group.
+   * 
+   * @return the singleton instance of the group
+   * @throws ViatraQueryRuntimeException if there was an error loading the generated code of pattern specifications
+   * 
+   */
+  public static FamilyTreeConstraints instance() {
+    if (INSTANCE == null) {
+        INSTANCE = new FamilyTreeConstraints();
+    }
+    return INSTANCE;
+  }
+  
+  private static FamilyTreeConstraints INSTANCE;
+  
+  private FamilyTreeConstraints() {
+    querySpecifications.add(MemberIsItsOwnParent.instance());
+    querySpecifications.add(TwoMembersHaveNoParent.instance());
+    querySpecifications.add(MemberHasParent.instance());
+    querySpecifications.add(NegativeAge.instance());
+    querySpecifications.add(ParentTooYoung.instance());
+  }
+  
+  public MemberIsItsOwnParent getMemberIsItsOwnParent() {
+    return MemberIsItsOwnParent.instance();
+  }
+  
+  public MemberIsItsOwnParent.Matcher getMemberIsItsOwnParent(final ViatraQueryEngine engine) {
+    return MemberIsItsOwnParent.Matcher.on(engine);
+  }
+  
+  public TwoMembersHaveNoParent getTwoMembersHaveNoParent() {
+    return TwoMembersHaveNoParent.instance();
+  }
+  
+  public TwoMembersHaveNoParent.Matcher getTwoMembersHaveNoParent(final ViatraQueryEngine engine) {
+    return TwoMembersHaveNoParent.Matcher.on(engine);
+  }
+  
+  public MemberHasParent getMemberHasParent() {
+    return MemberHasParent.instance();
+  }
+  
+  public MemberHasParent.Matcher getMemberHasParent(final ViatraQueryEngine engine) {
+    return MemberHasParent.Matcher.on(engine);
+  }
+  
+  public NegativeAge getNegativeAge() {
+    return NegativeAge.instance();
+  }
+  
+  public NegativeAge.Matcher getNegativeAge(final ViatraQueryEngine engine) {
+    return NegativeAge.Matcher.on(engine);
+  }
+  
+  public ParentTooYoung getParentTooYoung() {
+    return ParentTooYoung.instance();
+  }
+  
+  public ParentTooYoung.Matcher getParentTooYoung(final ViatraQueryEngine engine) {
+    return ParentTooYoung.Matcher.on(engine);
+  }
+}
diff --git a/Tests/MODELS2020-CaseStudies/case.study.familyTree.run/src-gen/queries/MemberHasParent.java b/Tests/MODELS2020-CaseStudies/case.study.familyTree.run/src-gen/queries/MemberHasParent.java
new file mode 100644
index 00000000..83bb4aac
--- /dev/null
+++ b/Tests/MODELS2020-CaseStudies/case.study.familyTree.run/src-gen/queries/MemberHasParent.java
@@ -0,0 +1,551 @@
+/**
+ * Generated from platform:/resource/case.study.familyTree.run/src/queries/familyTreeConstraints.vql
+ */
+package queries;
+
+import familytree.Member;
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.LinkedHashSet;
+import java.util.List;
+import java.util.Objects;
+import java.util.Optional;
+import java.util.Set;
+import java.util.function.Consumer;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
+import org.apache.log4j.Logger;
+import org.eclipse.emf.ecore.EClass;
+import org.eclipse.viatra.query.runtime.api.IPatternMatch;
+import org.eclipse.viatra.query.runtime.api.IQuerySpecification;
+import org.eclipse.viatra.query.runtime.api.ViatraQueryEngine;
+import org.eclipse.viatra.query.runtime.api.impl.BaseGeneratedEMFPQuery;
+import org.eclipse.viatra.query.runtime.api.impl.BaseGeneratedEMFQuerySpecification;
+import org.eclipse.viatra.query.runtime.api.impl.BaseMatcher;
+import org.eclipse.viatra.query.runtime.api.impl.BasePatternMatch;
+import org.eclipse.viatra.query.runtime.emf.types.EClassTransitiveInstancesKey;
+import org.eclipse.viatra.query.runtime.emf.types.EStructuralFeatureInstancesKey;
+import org.eclipse.viatra.query.runtime.matchers.backend.QueryEvaluationHint;
+import org.eclipse.viatra.query.runtime.matchers.psystem.PBody;
+import org.eclipse.viatra.query.runtime.matchers.psystem.PVariable;
+import org.eclipse.viatra.query.runtime.matchers.psystem.basicdeferred.Equality;
+import org.eclipse.viatra.query.runtime.matchers.psystem.basicdeferred.ExportedParameter;
+import org.eclipse.viatra.query.runtime.matchers.psystem.basicenumerables.TypeConstraint;
+import org.eclipse.viatra.query.runtime.matchers.psystem.queries.PParameter;
+import org.eclipse.viatra.query.runtime.matchers.psystem.queries.PParameterDirection;
+import org.eclipse.viatra.query.runtime.matchers.psystem.queries.PVisibility;
+import org.eclipse.viatra.query.runtime.matchers.tuple.Tuple;
+import org.eclipse.viatra.query.runtime.matchers.tuple.Tuples;
+import org.eclipse.viatra.query.runtime.util.ViatraQueryLoggingUtil;
+
+/**
+ * A pattern-specific query specification that can instantiate Matcher in a type-safe way.
+ * 
+ * <p>Original source:
+ *         <code><pre>
+ *         pattern memberHasParent(m: Member) = {
+ *              Member.parents(m, _);
+ *         }
+ * </pre></code>
+ * 
+ * @see Matcher
+ * @see Match
+ * 
+ */
+@SuppressWarnings("all")
+public final class MemberHasParent extends BaseGeneratedEMFQuerySpecification<MemberHasParent.Matcher> {
+  /**
+   * Pattern-specific match representation of the queries.memberHasParent pattern,
+   * to be used in conjunction with {@link Matcher}.
+   * 
+   * <p>Class fields correspond to parameters of the pattern. Fields with value null are considered unassigned.
+   * Each instance is a (possibly partial) substitution of pattern parameters,
+   * usable to represent a match of the pattern in the result of a query,
+   * or to specify the bound (fixed) input parameters when issuing a query.
+   * 
+   * @see Matcher
+   * 
+   */
+  public static abstract class Match extends BasePatternMatch {
+    private Member fM;
+    
+    private static List<String> parameterNames = makeImmutableList("m");
+    
+    private Match(final Member pM) {
+      this.fM = pM;
+    }
+    
+    @Override
+    public Object get(final String parameterName) {
+      switch(parameterName) {
+          case "m": return this.fM;
+          default: return null;
+      }
+    }
+    
+    @Override
+    public Object get(final int index) {
+      switch(index) {
+          case 0: return this.fM;
+          default: return null;
+      }
+    }
+    
+    public Member getM() {
+      return this.fM;
+    }
+    
+    @Override
+    public boolean set(final String parameterName, final Object newValue) {
+      if (!isMutable()) throw new java.lang.UnsupportedOperationException();
+      if ("m".equals(parameterName) ) {
+          this.fM = (Member) newValue;
+          return true;
+      }
+      return false;
+    }
+    
+    public void setM(final Member pM) {
+      if (!isMutable()) throw new java.lang.UnsupportedOperationException();
+      this.fM = pM;
+    }
+    
+    @Override
+    public String patternName() {
+      return "queries.memberHasParent";
+    }
+    
+    @Override
+    public List<String> parameterNames() {
+      return MemberHasParent.Match.parameterNames;
+    }
+    
+    @Override
+    public Object[] toArray() {
+      return new Object[]{fM};
+    }
+    
+    @Override
+    public MemberHasParent.Match toImmutable() {
+      return isMutable() ? newMatch(fM) : this;
+    }
+    
+    @Override
+    public String prettyPrint() {
+      StringBuilder result = new StringBuilder();
+      result.append("\"m\"=" + prettyPrintValue(fM));
+      return result.toString();
+    }
+    
+    @Override
+    public int hashCode() {
+      return Objects.hash(fM);
+    }
+    
+    @Override
+    public boolean equals(final Object obj) {
+      if (this == obj)
+          return true;
+      if (obj == null) {
+          return false;
+      }
+      if ((obj instanceof MemberHasParent.Match)) {
+          MemberHasParent.Match other = (MemberHasParent.Match) obj;
+          return Objects.equals(fM, other.fM);
+      } else {
+          // this should be infrequent
+          if (!(obj instanceof IPatternMatch)) {
+              return false;
+          }
+          IPatternMatch otherSig  = (IPatternMatch) obj;
+          return Objects.equals(specification(), otherSig.specification()) && Arrays.deepEquals(toArray(), otherSig.toArray());
+      }
+    }
+    
+    @Override
+    public MemberHasParent specification() {
+      return MemberHasParent.instance();
+    }
+    
+    /**
+     * Returns an empty, mutable match.
+     * Fields of the mutable match can be filled to create a partial match, usable as matcher input.
+     * 
+     * @return the empty match.
+     * 
+     */
+    public static MemberHasParent.Match newEmptyMatch() {
+      return new Mutable(null);
+    }
+    
+    /**
+     * Returns a mutable (partial) match.
+     * Fields of the mutable match can be filled to create a partial match, usable as matcher input.
+     * 
+     * @param pM the fixed value of pattern parameter m, or null if not bound.
+     * @return the new, mutable (partial) match object.
+     * 
+     */
+    public static MemberHasParent.Match newMutableMatch(final Member pM) {
+      return new Mutable(pM);
+    }
+    
+    /**
+     * Returns a new (partial) match.
+     * This can be used e.g. to call the matcher with a partial match.
+     * <p>The returned match will be immutable. Use {@link #newEmptyMatch()} to obtain a mutable match object.
+     * @param pM the fixed value of pattern parameter m, or null if not bound.
+     * @return the (partial) match object.
+     * 
+     */
+    public static MemberHasParent.Match newMatch(final Member pM) {
+      return new Immutable(pM);
+    }
+    
+    private static final class Mutable extends MemberHasParent.Match {
+      Mutable(final Member pM) {
+        super(pM);
+      }
+      
+      @Override
+      public boolean isMutable() {
+        return true;
+      }
+    }
+    
+    private static final class Immutable extends MemberHasParent.Match {
+      Immutable(final Member pM) {
+        super(pM);
+      }
+      
+      @Override
+      public boolean isMutable() {
+        return false;
+      }
+    }
+  }
+  
+  /**
+   * Generated pattern matcher API of the queries.memberHasParent pattern,
+   * providing pattern-specific query methods.
+   * 
+   * <p>Use the pattern matcher on a given model via {@link #on(ViatraQueryEngine)},
+   * e.g. in conjunction with {@link ViatraQueryEngine#on(QueryScope)}.
+   * 
+   * <p>Matches of the pattern will be represented as {@link Match}.
+   * 
+   * <p>Original source:
+   * <code><pre>
+   * pattern memberHasParent(m: Member) = {
+   *    Member.parents(m, _);
+   * }
+   * </pre></code>
+   * 
+   * @see Match
+   * @see MemberHasParent
+   * 
+   */
+  public static class Matcher extends BaseMatcher<MemberHasParent.Match> {
+    /**
+     * Initializes the pattern matcher within an existing VIATRA Query engine.
+     * If the pattern matcher is already constructed in the engine, only a light-weight reference is returned.
+     * 
+     * @param engine the existing VIATRA Query engine in which this matcher will be created.
+     * @throws ViatraQueryRuntimeException if an error occurs during pattern matcher creation
+     * 
+     */
+    public static MemberHasParent.Matcher on(final ViatraQueryEngine engine) {
+      // check if matcher already exists
+      Matcher matcher = engine.getExistingMatcher(querySpecification());
+      if (matcher == null) {
+          matcher = (Matcher)engine.getMatcher(querySpecification());
+      }
+      return matcher;
+    }
+    
+    /**
+     * @throws ViatraQueryRuntimeException if an error occurs during pattern matcher creation
+     * @return an initialized matcher
+     * @noreference This method is for internal matcher initialization by the framework, do not call it manually.
+     * 
+     */
+    public static MemberHasParent.Matcher create() {
+      return new Matcher();
+    }
+    
+    private static final int POSITION_M = 0;
+    
+    private static final Logger LOGGER = ViatraQueryLoggingUtil.getLogger(MemberHasParent.Matcher.class);
+    
+    /**
+     * Initializes the pattern matcher within an existing VIATRA Query engine.
+     * If the pattern matcher is already constructed in the engine, only a light-weight reference is returned.
+     * 
+     * @param engine the existing VIATRA Query engine in which this matcher will be created.
+     * @throws ViatraQueryRuntimeException if an error occurs during pattern matcher creation
+     * 
+     */
+    private Matcher() {
+      super(querySpecification());
+    }
+    
+    /**
+     * Returns the set of all matches of the pattern that conform to the given fixed values of some parameters.
+     * @param pM the fixed value of pattern parameter m, or null if not bound.
+     * @return matches represented as a Match object.
+     * 
+     */
+    public Collection<MemberHasParent.Match> getAllMatches(final Member pM) {
+      return rawStreamAllMatches(new Object[]{pM}).collect(Collectors.toSet());
+    }
+    
+    /**
+     * Returns a stream of all matches of the pattern that conform to the given fixed values of some parameters.
+     * </p>
+     * <strong>NOTE</strong>: It is important not to modify the source model while the stream is being processed.
+     * If the match set of the pattern changes during processing, the contents of the stream is <strong>undefined</strong>.
+     * In such cases, either rely on {@link #getAllMatches()} or collect the results of the stream in end-user code.
+     * @param pM the fixed value of pattern parameter m, or null if not bound.
+     * @return a stream of matches represented as a Match object.
+     * 
+     */
+    public Stream<MemberHasParent.Match> streamAllMatches(final Member pM) {
+      return rawStreamAllMatches(new Object[]{pM});
+    }
+    
+    /**
+     * Returns an arbitrarily chosen match of the pattern that conforms to the given fixed values of some parameters.
+     * Neither determinism nor randomness of selection is guaranteed.
+     * @param pM the fixed value of pattern parameter m, or null if not bound.
+     * @return a match represented as a Match object, or null if no match is found.
+     * 
+     */
+    public Optional<MemberHasParent.Match> getOneArbitraryMatch(final Member pM) {
+      return rawGetOneArbitraryMatch(new Object[]{pM});
+    }
+    
+    /**
+     * Indicates whether the given combination of specified pattern parameters constitute a valid pattern match,
+     * under any possible substitution of the unspecified parameters (if any).
+     * @param pM the fixed value of pattern parameter m, or null if not bound.
+     * @return true if the input is a valid (partial) match of the pattern.
+     * 
+     */
+    public boolean hasMatch(final Member pM) {
+      return rawHasMatch(new Object[]{pM});
+    }
+    
+    /**
+     * Returns the number of all matches of the pattern that conform to the given fixed values of some parameters.
+     * @param pM the fixed value of pattern parameter m, or null if not bound.
+     * @return the number of pattern matches found.
+     * 
+     */
+    public int countMatches(final Member pM) {
+      return rawCountMatches(new Object[]{pM});
+    }
+    
+    /**
+     * Executes the given processor on an arbitrarily chosen match of the pattern that conforms to the given fixed values of some parameters.
+     * Neither determinism nor randomness of selection is guaranteed.
+     * @param pM the fixed value of pattern parameter m, or null if not bound.
+     * @param processor the action that will process the selected match.
+     * @return true if the pattern has at least one match with the given parameter values, false if the processor was not invoked
+     * 
+     */
+    public boolean forOneArbitraryMatch(final Member pM, final Consumer<? super MemberHasParent.Match> processor) {
+      return rawForOneArbitraryMatch(new Object[]{pM}, processor);
+    }
+    
+    /**
+     * Returns a new (partial) match.
+     * This can be used e.g. to call the matcher with a partial match.
+     * <p>The returned match will be immutable. Use {@link #newEmptyMatch()} to obtain a mutable match object.
+     * @param pM the fixed value of pattern parameter m, or null if not bound.
+     * @return the (partial) match object.
+     * 
+     */
+    public MemberHasParent.Match newMatch(final Member pM) {
+      return MemberHasParent.Match.newMatch(pM);
+    }
+    
+    /**
+     * Retrieve the set of values that occur in matches for m.
+     * @return the Set of all values or empty set if there are no matches
+     * 
+     */
+    protected Stream<Member> rawStreamAllValuesOfm(final Object[] parameters) {
+      return rawStreamAllValues(POSITION_M, parameters).map(Member.class::cast);
+    }
+    
+    /**
+     * Retrieve the set of values that occur in matches for m.
+     * @return the Set of all values or empty set if there are no matches
+     * 
+     */
+    public Set<Member> getAllValuesOfm() {
+      return rawStreamAllValuesOfm(emptyArray()).collect(Collectors.toSet());
+    }
+    
+    /**
+     * Retrieve the set of values that occur in matches for m.
+     * @return the Set of all values or empty set if there are no matches
+     * 
+     */
+    public Stream<Member> streamAllValuesOfm() {
+      return rawStreamAllValuesOfm(emptyArray());
+    }
+    
+    @Override
+    protected MemberHasParent.Match tupleToMatch(final Tuple t) {
+      try {
+          return MemberHasParent.Match.newMatch((Member) t.get(POSITION_M));
+      } catch(ClassCastException e) {
+          LOGGER.error("Element(s) in tuple not properly typed!",e);
+          return null;
+      }
+    }
+    
+    @Override
+    protected MemberHasParent.Match arrayToMatch(final Object[] match) {
+      try {
+          return MemberHasParent.Match.newMatch((Member) match[POSITION_M]);
+      } catch(ClassCastException e) {
+          LOGGER.error("Element(s) in array not properly typed!",e);
+          return null;
+      }
+    }
+    
+    @Override
+    protected MemberHasParent.Match arrayToMatchMutable(final Object[] match) {
+      try {
+          return MemberHasParent.Match.newMutableMatch((Member) match[POSITION_M]);
+      } catch(ClassCastException e) {
+          LOGGER.error("Element(s) in array not properly typed!",e);
+          return null;
+      }
+    }
+    
+    /**
+     * @return the singleton instance of the query specification of this pattern
+     * @throws ViatraQueryRuntimeException if the pattern definition could not be loaded
+     * 
+     */
+    public static IQuerySpecification<MemberHasParent.Matcher> querySpecification() {
+      return MemberHasParent.instance();
+    }
+  }
+  
+  private MemberHasParent() {
+    super(GeneratedPQuery.INSTANCE);
+  }
+  
+  /**
+   * @return the singleton instance of the query specification
+   * @throws ViatraQueryRuntimeException if the pattern definition could not be loaded
+   * 
+   */
+  public static MemberHasParent instance() {
+    try{
+        return LazyHolder.INSTANCE;
+    } catch (ExceptionInInitializerError err) {
+        throw processInitializerError(err);
+    }
+  }
+  
+  @Override
+  protected MemberHasParent.Matcher instantiate(final ViatraQueryEngine engine) {
+    return MemberHasParent.Matcher.on(engine);
+  }
+  
+  @Override
+  public MemberHasParent.Matcher instantiate() {
+    return MemberHasParent.Matcher.create();
+  }
+  
+  @Override
+  public MemberHasParent.Match newEmptyMatch() {
+    return MemberHasParent.Match.newEmptyMatch();
+  }
+  
+  @Override
+  public MemberHasParent.Match newMatch(final Object... parameters) {
+    return MemberHasParent.Match.newMatch((familytree.Member) parameters[0]);
+  }
+  
+  /**
+   * Inner class allowing the singleton instance of {@link MemberHasParent} to be created 
+   *     <b>not</b> at the class load time of the outer class, 
+   *     but rather at the first call to {@link MemberHasParent#instance()}.
+   * 
+   * <p> This workaround is required e.g. to support recursion.
+   * 
+   */
+  private static class LazyHolder {
+    private static final MemberHasParent INSTANCE = new MemberHasParent();
+    
+    /**
+     * Statically initializes the query specification <b>after</b> the field {@link #INSTANCE} is assigned.
+     * This initialization order is required to support indirect recursion.
+     * 
+     * <p> The static initializer is defined using a helper field to work around limitations of the code generator.
+     * 
+     */
+    private static final Object STATIC_INITIALIZER = ensureInitialized();
+    
+    public static Object ensureInitialized() {
+      INSTANCE.ensureInitializedInternal();
+      return null;
+    }
+  }
+  
+  private static class GeneratedPQuery extends BaseGeneratedEMFPQuery {
+    private static final MemberHasParent.GeneratedPQuery INSTANCE = new GeneratedPQuery();
+    
+    private final PParameter parameter_m = new PParameter("m", "familytree.Member", new EClassTransitiveInstancesKey((EClass)getClassifierLiteralSafe("http://www.example.org/familytree", "Member")), PParameterDirection.INOUT);
+    
+    private final List<PParameter> parameters = Arrays.asList(parameter_m);
+    
+    private GeneratedPQuery() {
+      super(PVisibility.PUBLIC);
+    }
+    
+    @Override
+    public String getFullyQualifiedName() {
+      return "queries.memberHasParent";
+    }
+    
+    @Override
+    public List<String> getParameterNames() {
+      return Arrays.asList("m");
+    }
+    
+    @Override
+    public List<PParameter> getParameters() {
+      return parameters;
+    }
+    
+    @Override
+    public Set<PBody> doGetContainedBodies() {
+      setEvaluationHints(new QueryEvaluationHint(null, QueryEvaluationHint.BackendRequirement.UNSPECIFIED));
+      Set<PBody> bodies = new LinkedHashSet<>();
+      {
+          PBody body = new PBody(this);
+          PVariable var_m = body.getOrCreateVariableByName("m");
+          PVariable var___0_ = body.getOrCreateVariableByName("_<0>");
+          new TypeConstraint(body, Tuples.flatTupleOf(var_m), new EClassTransitiveInstancesKey((EClass)getClassifierLiteral("http://www.example.org/familytree", "Member")));
+          body.setSymbolicParameters(Arrays.<ExportedParameter>asList(
+             new ExportedParameter(body, var_m, parameter_m)
+          ));
+          //    Member.parents(m, _)
+          new TypeConstraint(body, Tuples.flatTupleOf(var_m), new EClassTransitiveInstancesKey((EClass)getClassifierLiteral("http://www.example.org/familytree", "Member")));
+          PVariable var__virtual_0_ = body.getOrCreateVariableByName(".virtual{0}");
+          new TypeConstraint(body, Tuples.flatTupleOf(var_m, var__virtual_0_), new EStructuralFeatureInstancesKey(getFeatureLiteral("http://www.example.org/familytree", "Member", "parents")));
+          new TypeConstraint(body, Tuples.flatTupleOf(var__virtual_0_), new EClassTransitiveInstancesKey((EClass)getClassifierLiteral("http://www.example.org/familytree", "Member")));
+          new Equality(body, var__virtual_0_, var___0_);
+          bodies.add(body);
+      }
+      return bodies;
+    }
+  }
+}
diff --git a/Tests/MODELS2020-CaseStudies/case.study.familyTree.run/src-gen/queries/MemberIsItsOwnParent.java b/Tests/MODELS2020-CaseStudies/case.study.familyTree.run/src-gen/queries/MemberIsItsOwnParent.java
index 67cdafb5..63cb882d 100644
--- a/Tests/MODELS2020-CaseStudies/case.study.familyTree.run/src-gen/queries/MemberIsItsOwnParent.java
+++ b/Tests/MODELS2020-CaseStudies/case.study.familyTree.run/src-gen/queries/MemberIsItsOwnParent.java
@@ -1,577 +1,577 @@
-/**

- * Generated from platform:/resource/case.study.familyTree.run/src/queries/familyTreeConstraints.vql

- */

-package queries;

-

-import familytree.Member;

-import java.util.Arrays;

-import java.util.Collection;

-import java.util.LinkedHashSet;

-import java.util.List;

-import java.util.Objects;

-import java.util.Optional;

-import java.util.Set;

-import java.util.function.Consumer;

-import java.util.stream.Collectors;

-import java.util.stream.Stream;

-import org.apache.log4j.Logger;

-import org.eclipse.emf.ecore.EClass;

-import org.eclipse.viatra.query.runtime.api.IPatternMatch;

-import org.eclipse.viatra.query.runtime.api.IQuerySpecification;

-import org.eclipse.viatra.query.runtime.api.ViatraQueryEngine;

-import org.eclipse.viatra.query.runtime.api.impl.BaseGeneratedEMFPQuery;

-import org.eclipse.viatra.query.runtime.api.impl.BaseGeneratedEMFQuerySpecification;

-import org.eclipse.viatra.query.runtime.api.impl.BaseMatcher;

-import org.eclipse.viatra.query.runtime.api.impl.BasePatternMatch;

-import org.eclipse.viatra.query.runtime.emf.types.EClassTransitiveInstancesKey;

-import org.eclipse.viatra.query.runtime.emf.types.EStructuralFeatureInstancesKey;

-import org.eclipse.viatra.query.runtime.matchers.backend.QueryEvaluationHint;

-import org.eclipse.viatra.query.runtime.matchers.psystem.PBody;

-import org.eclipse.viatra.query.runtime.matchers.psystem.PVariable;

-import org.eclipse.viatra.query.runtime.matchers.psystem.annotations.PAnnotation;

-import org.eclipse.viatra.query.runtime.matchers.psystem.annotations.ParameterReference;

-import org.eclipse.viatra.query.runtime.matchers.psystem.basicdeferred.Equality;

-import org.eclipse.viatra.query.runtime.matchers.psystem.basicdeferred.ExportedParameter;

-import org.eclipse.viatra.query.runtime.matchers.psystem.basicenumerables.TypeConstraint;

-import org.eclipse.viatra.query.runtime.matchers.psystem.queries.PParameter;

-import org.eclipse.viatra.query.runtime.matchers.psystem.queries.PParameterDirection;

-import org.eclipse.viatra.query.runtime.matchers.psystem.queries.PVisibility;

-import org.eclipse.viatra.query.runtime.matchers.tuple.Tuple;

-import org.eclipse.viatra.query.runtime.matchers.tuple.Tuples;

-import org.eclipse.viatra.query.runtime.util.ViatraQueryLoggingUtil;

-

-/**

- * A pattern-specific query specification that can instantiate Matcher in a type-safe way.

- * 

- * <p>Original source:

- *         <code><pre>

- *         {@literal @}Constraint(message="memberIsItsOwnParent", severity="error", key={m})

- *         pattern memberIsItsOwnParent(m: Member) = {

- *              FamilyTree.members(_, m);

- *              Member.parents(m, p);

- *              m == p;

- *         }

- * </pre></code>

- * 

- * @see Matcher

- * @see Match

- * 

- */

-@SuppressWarnings("all")

-public final class MemberIsItsOwnParent extends BaseGeneratedEMFQuerySpecification<MemberIsItsOwnParent.Matcher> {

-  /**

-   * Pattern-specific match representation of the queries.memberIsItsOwnParent pattern,

-   * to be used in conjunction with {@link Matcher}.

-   * 

-   * <p>Class fields correspond to parameters of the pattern. Fields with value null are considered unassigned.

-   * Each instance is a (possibly partial) substitution of pattern parameters,

-   * usable to represent a match of the pattern in the result of a query,

-   * or to specify the bound (fixed) input parameters when issuing a query.

-   * 

-   * @see Matcher

-   * 

-   */

-  public static abstract class Match extends BasePatternMatch {

-    private Member fM;

-    

-    private static List<String> parameterNames = makeImmutableList("m");

-    

-    private Match(final Member pM) {

-      this.fM = pM;

-    }

-    

-    @Override

-    public Object get(final String parameterName) {

-      switch(parameterName) {

-          case "m": return this.fM;

-          default: return null;

-      }

-    }

-    

-    @Override

-    public Object get(final int index) {

-      switch(index) {

-          case 0: return this.fM;

-          default: return null;

-      }

-    }

-    

-    public Member getM() {

-      return this.fM;

-    }

-    

-    @Override

-    public boolean set(final String parameterName, final Object newValue) {

-      if (!isMutable()) throw new java.lang.UnsupportedOperationException();

-      if ("m".equals(parameterName) ) {

-          this.fM = (Member) newValue;

-          return true;

-      }

-      return false;

-    }

-    

-    public void setM(final Member pM) {

-      if (!isMutable()) throw new java.lang.UnsupportedOperationException();

-      this.fM = pM;

-    }

-    

-    @Override

-    public String patternName() {

-      return "queries.memberIsItsOwnParent";

-    }

-    

-    @Override

-    public List<String> parameterNames() {

-      return MemberIsItsOwnParent.Match.parameterNames;

-    }

-    

-    @Override

-    public Object[] toArray() {

-      return new Object[]{fM};

-    }

-    

-    @Override

-    public MemberIsItsOwnParent.Match toImmutable() {

-      return isMutable() ? newMatch(fM) : this;

-    }

-    

-    @Override

-    public String prettyPrint() {

-      StringBuilder result = new StringBuilder();

-      result.append("\"m\"=" + prettyPrintValue(fM));

-      return result.toString();

-    }

-    

-    @Override

-    public int hashCode() {

-      return Objects.hash(fM);

-    }

-    

-    @Override

-    public boolean equals(final Object obj) {

-      if (this == obj)

-          return true;

-      if (obj == null) {

-          return false;

-      }

-      if ((obj instanceof MemberIsItsOwnParent.Match)) {

-          MemberIsItsOwnParent.Match other = (MemberIsItsOwnParent.Match) obj;

-          return Objects.equals(fM, other.fM);

-      } else {

-          // this should be infrequent

-          if (!(obj instanceof IPatternMatch)) {

-              return false;

-          }

-          IPatternMatch otherSig  = (IPatternMatch) obj;

-          return Objects.equals(specification(), otherSig.specification()) && Arrays.deepEquals(toArray(), otherSig.toArray());

-      }

-    }

-    

-    @Override

-    public MemberIsItsOwnParent specification() {

-      return MemberIsItsOwnParent.instance();

-    }

-    

-    /**

-     * Returns an empty, mutable match.

-     * Fields of the mutable match can be filled to create a partial match, usable as matcher input.

-     * 

-     * @return the empty match.

-     * 

-     */

-    public static MemberIsItsOwnParent.Match newEmptyMatch() {

-      return new Mutable(null);

-    }

-    

-    /**

-     * Returns a mutable (partial) match.

-     * Fields of the mutable match can be filled to create a partial match, usable as matcher input.

-     * 

-     * @param pM the fixed value of pattern parameter m, or null if not bound.

-     * @return the new, mutable (partial) match object.

-     * 

-     */

-    public static MemberIsItsOwnParent.Match newMutableMatch(final Member pM) {

-      return new Mutable(pM);

-    }

-    

-    /**

-     * Returns a new (partial) match.

-     * This can be used e.g. to call the matcher with a partial match.

-     * <p>The returned match will be immutable. Use {@link #newEmptyMatch()} to obtain a mutable match object.

-     * @param pM the fixed value of pattern parameter m, or null if not bound.

-     * @return the (partial) match object.

-     * 

-     */

-    public static MemberIsItsOwnParent.Match newMatch(final Member pM) {

-      return new Immutable(pM);

-    }

-    

-    private static final class Mutable extends MemberIsItsOwnParent.Match {

-      Mutable(final Member pM) {

-        super(pM);

-      }

-      

-      @Override

-      public boolean isMutable() {

-        return true;

-      }

-    }

-    

-    private static final class Immutable extends MemberIsItsOwnParent.Match {

-      Immutable(final Member pM) {

-        super(pM);

-      }

-      

-      @Override

-      public boolean isMutable() {

-        return false;

-      }

-    }

-  }

-  

-  /**

-   * Generated pattern matcher API of the queries.memberIsItsOwnParent pattern,

-   * providing pattern-specific query methods.

-   * 

-   * <p>Use the pattern matcher on a given model via {@link #on(ViatraQueryEngine)},

-   * e.g. in conjunction with {@link ViatraQueryEngine#on(QueryScope)}.

-   * 

-   * <p>Matches of the pattern will be represented as {@link Match}.

-   * 

-   * <p>Original source:

-   * <code><pre>

-   * {@literal @}Constraint(message="memberIsItsOwnParent", severity="error", key={m})

-   * pattern memberIsItsOwnParent(m: Member) = {

-   *    FamilyTree.members(_, m);

-   *    Member.parents(m, p);

-   *    m == p;

-   * }

-   * </pre></code>

-   * 

-   * @see Match

-   * @see MemberIsItsOwnParent

-   * 

-   */

-  public static class Matcher extends BaseMatcher<MemberIsItsOwnParent.Match> {

-    /**

-     * Initializes the pattern matcher within an existing VIATRA Query engine.

-     * If the pattern matcher is already constructed in the engine, only a light-weight reference is returned.

-     * 

-     * @param engine the existing VIATRA Query engine in which this matcher will be created.

-     * @throws ViatraQueryRuntimeException if an error occurs during pattern matcher creation

-     * 

-     */

-    public static MemberIsItsOwnParent.Matcher on(final ViatraQueryEngine engine) {

-      // check if matcher already exists

-      Matcher matcher = engine.getExistingMatcher(querySpecification());

-      if (matcher == null) {

-          matcher = (Matcher)engine.getMatcher(querySpecification());

-      }

-      return matcher;

-    }

-    

-    /**

-     * @throws ViatraQueryRuntimeException if an error occurs during pattern matcher creation

-     * @return an initialized matcher

-     * @noreference This method is for internal matcher initialization by the framework, do not call it manually.

-     * 

-     */

-    public static MemberIsItsOwnParent.Matcher create() {

-      return new Matcher();

-    }

-    

-    private static final int POSITION_M = 0;

-    

-    private static final Logger LOGGER = ViatraQueryLoggingUtil.getLogger(MemberIsItsOwnParent.Matcher.class);

-    

-    /**

-     * Initializes the pattern matcher within an existing VIATRA Query engine.

-     * If the pattern matcher is already constructed in the engine, only a light-weight reference is returned.

-     * 

-     * @param engine the existing VIATRA Query engine in which this matcher will be created.

-     * @throws ViatraQueryRuntimeException if an error occurs during pattern matcher creation

-     * 

-     */

-    private Matcher() {

-      super(querySpecification());

-    }

-    

-    /**

-     * Returns the set of all matches of the pattern that conform to the given fixed values of some parameters.

-     * @param pM the fixed value of pattern parameter m, or null if not bound.

-     * @return matches represented as a Match object.

-     * 

-     */

-    public Collection<MemberIsItsOwnParent.Match> getAllMatches(final Member pM) {

-      return rawStreamAllMatches(new Object[]{pM}).collect(Collectors.toSet());

-    }

-    

-    /**

-     * Returns a stream of all matches of the pattern that conform to the given fixed values of some parameters.

-     * </p>

-     * <strong>NOTE</strong>: It is important not to modify the source model while the stream is being processed.

-     * If the match set of the pattern changes during processing, the contents of the stream is <strong>undefined</strong>.

-     * In such cases, either rely on {@link #getAllMatches()} or collect the results of the stream in end-user code.

-     * @param pM the fixed value of pattern parameter m, or null if not bound.

-     * @return a stream of matches represented as a Match object.

-     * 

-     */

-    public Stream<MemberIsItsOwnParent.Match> streamAllMatches(final Member pM) {

-      return rawStreamAllMatches(new Object[]{pM});

-    }

-    

-    /**

-     * Returns an arbitrarily chosen match of the pattern that conforms to the given fixed values of some parameters.

-     * Neither determinism nor randomness of selection is guaranteed.

-     * @param pM the fixed value of pattern parameter m, or null if not bound.

-     * @return a match represented as a Match object, or null if no match is found.

-     * 

-     */

-    public Optional<MemberIsItsOwnParent.Match> getOneArbitraryMatch(final Member pM) {

-      return rawGetOneArbitraryMatch(new Object[]{pM});

-    }

-    

-    /**

-     * Indicates whether the given combination of specified pattern parameters constitute a valid pattern match,

-     * under any possible substitution of the unspecified parameters (if any).

-     * @param pM the fixed value of pattern parameter m, or null if not bound.

-     * @return true if the input is a valid (partial) match of the pattern.

-     * 

-     */

-    public boolean hasMatch(final Member pM) {

-      return rawHasMatch(new Object[]{pM});

-    }

-    

-    /**

-     * Returns the number of all matches of the pattern that conform to the given fixed values of some parameters.

-     * @param pM the fixed value of pattern parameter m, or null if not bound.

-     * @return the number of pattern matches found.

-     * 

-     */

-    public int countMatches(final Member pM) {

-      return rawCountMatches(new Object[]{pM});

-    }

-    

-    /**

-     * Executes the given processor on an arbitrarily chosen match of the pattern that conforms to the given fixed values of some parameters.

-     * Neither determinism nor randomness of selection is guaranteed.

-     * @param pM the fixed value of pattern parameter m, or null if not bound.

-     * @param processor the action that will process the selected match.

-     * @return true if the pattern has at least one match with the given parameter values, false if the processor was not invoked

-     * 

-     */

-    public boolean forOneArbitraryMatch(final Member pM, final Consumer<? super MemberIsItsOwnParent.Match> processor) {

-      return rawForOneArbitraryMatch(new Object[]{pM}, processor);

-    }

-    

-    /**

-     * Returns a new (partial) match.

-     * This can be used e.g. to call the matcher with a partial match.

-     * <p>The returned match will be immutable. Use {@link #newEmptyMatch()} to obtain a mutable match object.

-     * @param pM the fixed value of pattern parameter m, or null if not bound.

-     * @return the (partial) match object.

-     * 

-     */

-    public MemberIsItsOwnParent.Match newMatch(final Member pM) {

-      return MemberIsItsOwnParent.Match.newMatch(pM);

-    }

-    

-    /**

-     * Retrieve the set of values that occur in matches for m.

-     * @return the Set of all values or empty set if there are no matches

-     * 

-     */

-    protected Stream<Member> rawStreamAllValuesOfm(final Object[] parameters) {

-      return rawStreamAllValues(POSITION_M, parameters).map(Member.class::cast);

-    }

-    

-    /**

-     * Retrieve the set of values that occur in matches for m.

-     * @return the Set of all values or empty set if there are no matches

-     * 

-     */

-    public Set<Member> getAllValuesOfm() {

-      return rawStreamAllValuesOfm(emptyArray()).collect(Collectors.toSet());

-    }

-    

-    /**

-     * Retrieve the set of values that occur in matches for m.

-     * @return the Set of all values or empty set if there are no matches

-     * 

-     */

-    public Stream<Member> streamAllValuesOfm() {

-      return rawStreamAllValuesOfm(emptyArray());

-    }

-    

-    @Override

-    protected MemberIsItsOwnParent.Match tupleToMatch(final Tuple t) {

-      try {

-          return MemberIsItsOwnParent.Match.newMatch((Member) t.get(POSITION_M));

-      } catch(ClassCastException e) {

-          LOGGER.error("Element(s) in tuple not properly typed!",e);

-          return null;

-      }

-    }

-    

-    @Override

-    protected MemberIsItsOwnParent.Match arrayToMatch(final Object[] match) {

-      try {

-          return MemberIsItsOwnParent.Match.newMatch((Member) match[POSITION_M]);

-      } catch(ClassCastException e) {

-          LOGGER.error("Element(s) in array not properly typed!",e);

-          return null;

-      }

-    }

-    

-    @Override

-    protected MemberIsItsOwnParent.Match arrayToMatchMutable(final Object[] match) {

-      try {

-          return MemberIsItsOwnParent.Match.newMutableMatch((Member) match[POSITION_M]);

-      } catch(ClassCastException e) {

-          LOGGER.error("Element(s) in array not properly typed!",e);

-          return null;

-      }

-    }

-    

-    /**

-     * @return the singleton instance of the query specification of this pattern

-     * @throws ViatraQueryRuntimeException if the pattern definition could not be loaded

-     * 

-     */

-    public static IQuerySpecification<MemberIsItsOwnParent.Matcher> querySpecification() {

-      return MemberIsItsOwnParent.instance();

-    }

-  }

-  

-  private MemberIsItsOwnParent() {

-    super(GeneratedPQuery.INSTANCE);

-  }

-  

-  /**

-   * @return the singleton instance of the query specification

-   * @throws ViatraQueryRuntimeException if the pattern definition could not be loaded

-   * 

-   */

-  public static MemberIsItsOwnParent instance() {

-    try{

-        return LazyHolder.INSTANCE;

-    } catch (ExceptionInInitializerError err) {

-        throw processInitializerError(err);

-    }

-  }

-  

-  @Override

-  protected MemberIsItsOwnParent.Matcher instantiate(final ViatraQueryEngine engine) {

-    return MemberIsItsOwnParent.Matcher.on(engine);

-  }

-  

-  @Override

-  public MemberIsItsOwnParent.Matcher instantiate() {

-    return MemberIsItsOwnParent.Matcher.create();

-  }

-  

-  @Override

-  public MemberIsItsOwnParent.Match newEmptyMatch() {

-    return MemberIsItsOwnParent.Match.newEmptyMatch();

-  }

-  

-  @Override

-  public MemberIsItsOwnParent.Match newMatch(final Object... parameters) {

-    return MemberIsItsOwnParent.Match.newMatch((familytree.Member) parameters[0]);

-  }

-  

-  /**

-   * Inner class allowing the singleton instance of {@link MemberIsItsOwnParent} to be created 

-   *     <b>not</b> at the class load time of the outer class, 

-   *     but rather at the first call to {@link MemberIsItsOwnParent#instance()}.

-   * 

-   * <p> This workaround is required e.g. to support recursion.

-   * 

-   */

-  private static class LazyHolder {

-    private static final MemberIsItsOwnParent INSTANCE = new MemberIsItsOwnParent();

-    

-    /**

-     * Statically initializes the query specification <b>after</b> the field {@link #INSTANCE} is assigned.

-     * This initialization order is required to support indirect recursion.

-     * 

-     * <p> The static initializer is defined using a helper field to work around limitations of the code generator.

-     * 

-     */

-    private static final Object STATIC_INITIALIZER = ensureInitialized();

-    

-    public static Object ensureInitialized() {

-      INSTANCE.ensureInitializedInternal();

-      return null;

-    }

-  }

-  

-  private static class GeneratedPQuery extends BaseGeneratedEMFPQuery {

-    private static final MemberIsItsOwnParent.GeneratedPQuery INSTANCE = new GeneratedPQuery();

-    

-    private final PParameter parameter_m = new PParameter("m", "familytree.Member", new EClassTransitiveInstancesKey((EClass)getClassifierLiteralSafe("http://www.example.org/familytree", "Member")), PParameterDirection.INOUT);

-    

-    private final List<PParameter> parameters = Arrays.asList(parameter_m);

-    

-    private GeneratedPQuery() {

-      super(PVisibility.PUBLIC);

-    }

-    

-    @Override

-    public String getFullyQualifiedName() {

-      return "queries.memberIsItsOwnParent";

-    }

-    

-    @Override

-    public List<String> getParameterNames() {

-      return Arrays.asList("m");

-    }

-    

-    @Override

-    public List<PParameter> getParameters() {

-      return parameters;

-    }

-    

-    @Override

-    public Set<PBody> doGetContainedBodies() {

-      setEvaluationHints(new QueryEvaluationHint(null, QueryEvaluationHint.BackendRequirement.UNSPECIFIED));

-      Set<PBody> bodies = new LinkedHashSet<>();

-      {

-          PBody body = new PBody(this);

-          PVariable var_m = body.getOrCreateVariableByName("m");

-          PVariable var___0_ = body.getOrCreateVariableByName("_<0>");

-          PVariable var_p = body.getOrCreateVariableByName("p");

-          new TypeConstraint(body, Tuples.flatTupleOf(var_m), new EClassTransitiveInstancesKey((EClass)getClassifierLiteral("http://www.example.org/familytree", "Member")));

-          body.setSymbolicParameters(Arrays.<ExportedParameter>asList(

-             new ExportedParameter(body, var_m, parameter_m)

-          ));

-          //    FamilyTree.members(_, m)

-          new TypeConstraint(body, Tuples.flatTupleOf(var___0_), new EClassTransitiveInstancesKey((EClass)getClassifierLiteral("http://www.example.org/familytree", "FamilyTree")));

-          PVariable var__virtual_0_ = body.getOrCreateVariableByName(".virtual{0}");

-          new TypeConstraint(body, Tuples.flatTupleOf(var___0_, var__virtual_0_), new EStructuralFeatureInstancesKey(getFeatureLiteral("http://www.example.org/familytree", "FamilyTree", "members")));

-          new TypeConstraint(body, Tuples.flatTupleOf(var__virtual_0_), new EClassTransitiveInstancesKey((EClass)getClassifierLiteral("http://www.example.org/familytree", "Member")));

-          new Equality(body, var__virtual_0_, var_m);

-          //    Member.parents(m, p)

-          new TypeConstraint(body, Tuples.flatTupleOf(var_m), new EClassTransitiveInstancesKey((EClass)getClassifierLiteral("http://www.example.org/familytree", "Member")));

-          PVariable var__virtual_1_ = body.getOrCreateVariableByName(".virtual{1}");

-          new TypeConstraint(body, Tuples.flatTupleOf(var_m, var__virtual_1_), new EStructuralFeatureInstancesKey(getFeatureLiteral("http://www.example.org/familytree", "Member", "parents")));

-          new TypeConstraint(body, Tuples.flatTupleOf(var__virtual_1_), new EClassTransitiveInstancesKey((EClass)getClassifierLiteral("http://www.example.org/familytree", "Member")));

-          new Equality(body, var__virtual_1_, var_p);

-          //    m == p

-          new Equality(body, var_m, var_p);

-          bodies.add(body);

-      }

-      {

-          PAnnotation annotation = new PAnnotation("Constraint");

-          annotation.addAttribute("message", "memberIsItsOwnParent");

-          annotation.addAttribute("severity", "error");

-          annotation.addAttribute("key", Arrays.asList(new Object[] {

-                              new ParameterReference("m")

-                              }));

-          addAnnotation(annotation);

-      }

-      return bodies;

-    }

-  }

-}

+/**
+ * Generated from platform:/resource/case.study.familyTree.run/src/queries/familyTreeConstraints.vql
+ */
+package queries;
+
+import familytree.Member;
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.LinkedHashSet;
+import java.util.List;
+import java.util.Objects;
+import java.util.Optional;
+import java.util.Set;
+import java.util.function.Consumer;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
+import org.apache.log4j.Logger;
+import org.eclipse.emf.ecore.EClass;
+import org.eclipse.viatra.query.runtime.api.IPatternMatch;
+import org.eclipse.viatra.query.runtime.api.IQuerySpecification;
+import org.eclipse.viatra.query.runtime.api.ViatraQueryEngine;
+import org.eclipse.viatra.query.runtime.api.impl.BaseGeneratedEMFPQuery;
+import org.eclipse.viatra.query.runtime.api.impl.BaseGeneratedEMFQuerySpecification;
+import org.eclipse.viatra.query.runtime.api.impl.BaseMatcher;
+import org.eclipse.viatra.query.runtime.api.impl.BasePatternMatch;
+import org.eclipse.viatra.query.runtime.emf.types.EClassTransitiveInstancesKey;
+import org.eclipse.viatra.query.runtime.emf.types.EStructuralFeatureInstancesKey;
+import org.eclipse.viatra.query.runtime.matchers.backend.QueryEvaluationHint;
+import org.eclipse.viatra.query.runtime.matchers.psystem.PBody;
+import org.eclipse.viatra.query.runtime.matchers.psystem.PVariable;
+import org.eclipse.viatra.query.runtime.matchers.psystem.annotations.PAnnotation;
+import org.eclipse.viatra.query.runtime.matchers.psystem.annotations.ParameterReference;
+import org.eclipse.viatra.query.runtime.matchers.psystem.basicdeferred.Equality;
+import org.eclipse.viatra.query.runtime.matchers.psystem.basicdeferred.ExportedParameter;
+import org.eclipse.viatra.query.runtime.matchers.psystem.basicenumerables.TypeConstraint;
+import org.eclipse.viatra.query.runtime.matchers.psystem.queries.PParameter;
+import org.eclipse.viatra.query.runtime.matchers.psystem.queries.PParameterDirection;
+import org.eclipse.viatra.query.runtime.matchers.psystem.queries.PVisibility;
+import org.eclipse.viatra.query.runtime.matchers.tuple.Tuple;
+import org.eclipse.viatra.query.runtime.matchers.tuple.Tuples;
+import org.eclipse.viatra.query.runtime.util.ViatraQueryLoggingUtil;
+
+/**
+ * A pattern-specific query specification that can instantiate Matcher in a type-safe way.
+ * 
+ * <p>Original source:
+ *         <code><pre>
+ *         {@literal @}Constraint(message="memberIsItsOwnParent", severity="error", key={m})
+ *         pattern memberIsItsOwnParent(m: Member) = {
+ *              FamilyTree.members(_, m);
+ *              Member.parents(m, p);
+ *              m == p;
+ *         }
+ * </pre></code>
+ * 
+ * @see Matcher
+ * @see Match
+ * 
+ */
+@SuppressWarnings("all")
+public final class MemberIsItsOwnParent extends BaseGeneratedEMFQuerySpecification<MemberIsItsOwnParent.Matcher> {
+  /**
+   * Pattern-specific match representation of the queries.memberIsItsOwnParent pattern,
+   * to be used in conjunction with {@link Matcher}.
+   * 
+   * <p>Class fields correspond to parameters of the pattern. Fields with value null are considered unassigned.
+   * Each instance is a (possibly partial) substitution of pattern parameters,
+   * usable to represent a match of the pattern in the result of a query,
+   * or to specify the bound (fixed) input parameters when issuing a query.
+   * 
+   * @see Matcher
+   * 
+   */
+  public static abstract class Match extends BasePatternMatch {
+    private Member fM;
+    
+    private static List<String> parameterNames = makeImmutableList("m");
+    
+    private Match(final Member pM) {
+      this.fM = pM;
+    }
+    
+    @Override
+    public Object get(final String parameterName) {
+      switch(parameterName) {
+          case "m": return this.fM;
+          default: return null;
+      }
+    }
+    
+    @Override
+    public Object get(final int index) {
+      switch(index) {
+          case 0: return this.fM;
+          default: return null;
+      }
+    }
+    
+    public Member getM() {
+      return this.fM;
+    }
+    
+    @Override
+    public boolean set(final String parameterName, final Object newValue) {
+      if (!isMutable()) throw new java.lang.UnsupportedOperationException();
+      if ("m".equals(parameterName) ) {
+          this.fM = (Member) newValue;
+          return true;
+      }
+      return false;
+    }
+    
+    public void setM(final Member pM) {
+      if (!isMutable()) throw new java.lang.UnsupportedOperationException();
+      this.fM = pM;
+    }
+    
+    @Override
+    public String patternName() {
+      return "queries.memberIsItsOwnParent";
+    }
+    
+    @Override
+    public List<String> parameterNames() {
+      return MemberIsItsOwnParent.Match.parameterNames;
+    }
+    
+    @Override
+    public Object[] toArray() {
+      return new Object[]{fM};
+    }
+    
+    @Override
+    public MemberIsItsOwnParent.Match toImmutable() {
+      return isMutable() ? newMatch(fM) : this;
+    }
+    
+    @Override
+    public String prettyPrint() {
+      StringBuilder result = new StringBuilder();
+      result.append("\"m\"=" + prettyPrintValue(fM));
+      return result.toString();
+    }
+    
+    @Override
+    public int hashCode() {
+      return Objects.hash(fM);
+    }
+    
+    @Override
+    public boolean equals(final Object obj) {
+      if (this == obj)
+          return true;
+      if (obj == null) {
+          return false;
+      }
+      if ((obj instanceof MemberIsItsOwnParent.Match)) {
+          MemberIsItsOwnParent.Match other = (MemberIsItsOwnParent.Match) obj;
+          return Objects.equals(fM, other.fM);
+      } else {
+          // this should be infrequent
+          if (!(obj instanceof IPatternMatch)) {
+              return false;
+          }
+          IPatternMatch otherSig  = (IPatternMatch) obj;
+          return Objects.equals(specification(), otherSig.specification()) && Arrays.deepEquals(toArray(), otherSig.toArray());
+      }
+    }
+    
+    @Override
+    public MemberIsItsOwnParent specification() {
+      return MemberIsItsOwnParent.instance();
+    }
+    
+    /**
+     * Returns an empty, mutable match.
+     * Fields of the mutable match can be filled to create a partial match, usable as matcher input.
+     * 
+     * @return the empty match.
+     * 
+     */
+    public static MemberIsItsOwnParent.Match newEmptyMatch() {
+      return new Mutable(null);
+    }
+    
+    /**
+     * Returns a mutable (partial) match.
+     * Fields of the mutable match can be filled to create a partial match, usable as matcher input.
+     * 
+     * @param pM the fixed value of pattern parameter m, or null if not bound.
+     * @return the new, mutable (partial) match object.
+     * 
+     */
+    public static MemberIsItsOwnParent.Match newMutableMatch(final Member pM) {
+      return new Mutable(pM);
+    }
+    
+    /**
+     * Returns a new (partial) match.
+     * This can be used e.g. to call the matcher with a partial match.
+     * <p>The returned match will be immutable. Use {@link #newEmptyMatch()} to obtain a mutable match object.
+     * @param pM the fixed value of pattern parameter m, or null if not bound.
+     * @return the (partial) match object.
+     * 
+     */
+    public static MemberIsItsOwnParent.Match newMatch(final Member pM) {
+      return new Immutable(pM);
+    }
+    
+    private static final class Mutable extends MemberIsItsOwnParent.Match {
+      Mutable(final Member pM) {
+        super(pM);
+      }
+      
+      @Override
+      public boolean isMutable() {
+        return true;
+      }
+    }
+    
+    private static final class Immutable extends MemberIsItsOwnParent.Match {
+      Immutable(final Member pM) {
+        super(pM);
+      }
+      
+      @Override
+      public boolean isMutable() {
+        return false;
+      }
+    }
+  }
+  
+  /**
+   * Generated pattern matcher API of the queries.memberIsItsOwnParent pattern,
+   * providing pattern-specific query methods.
+   * 
+   * <p>Use the pattern matcher on a given model via {@link #on(ViatraQueryEngine)},
+   * e.g. in conjunction with {@link ViatraQueryEngine#on(QueryScope)}.
+   * 
+   * <p>Matches of the pattern will be represented as {@link Match}.
+   * 
+   * <p>Original source:
+   * <code><pre>
+   * {@literal @}Constraint(message="memberIsItsOwnParent", severity="error", key={m})
+   * pattern memberIsItsOwnParent(m: Member) = {
+   *    FamilyTree.members(_, m);
+   *    Member.parents(m, p);
+   *    m == p;
+   * }
+   * </pre></code>
+   * 
+   * @see Match
+   * @see MemberIsItsOwnParent
+   * 
+   */
+  public static class Matcher extends BaseMatcher<MemberIsItsOwnParent.Match> {
+    /**
+     * Initializes the pattern matcher within an existing VIATRA Query engine.
+     * If the pattern matcher is already constructed in the engine, only a light-weight reference is returned.
+     * 
+     * @param engine the existing VIATRA Query engine in which this matcher will be created.
+     * @throws ViatraQueryRuntimeException if an error occurs during pattern matcher creation
+     * 
+     */
+    public static MemberIsItsOwnParent.Matcher on(final ViatraQueryEngine engine) {
+      // check if matcher already exists
+      Matcher matcher = engine.getExistingMatcher(querySpecification());
+      if (matcher == null) {
+          matcher = (Matcher)engine.getMatcher(querySpecification());
+      }
+      return matcher;
+    }
+    
+    /**
+     * @throws ViatraQueryRuntimeException if an error occurs during pattern matcher creation
+     * @return an initialized matcher
+     * @noreference This method is for internal matcher initialization by the framework, do not call it manually.
+     * 
+     */
+    public static MemberIsItsOwnParent.Matcher create() {
+      return new Matcher();
+    }
+    
+    private static final int POSITION_M = 0;
+    
+    private static final Logger LOGGER = ViatraQueryLoggingUtil.getLogger(MemberIsItsOwnParent.Matcher.class);
+    
+    /**
+     * Initializes the pattern matcher within an existing VIATRA Query engine.
+     * If the pattern matcher is already constructed in the engine, only a light-weight reference is returned.
+     * 
+     * @param engine the existing VIATRA Query engine in which this matcher will be created.
+     * @throws ViatraQueryRuntimeException if an error occurs during pattern matcher creation
+     * 
+     */
+    private Matcher() {
+      super(querySpecification());
+    }
+    
+    /**
+     * Returns the set of all matches of the pattern that conform to the given fixed values of some parameters.
+     * @param pM the fixed value of pattern parameter m, or null if not bound.
+     * @return matches represented as a Match object.
+     * 
+     */
+    public Collection<MemberIsItsOwnParent.Match> getAllMatches(final Member pM) {
+      return rawStreamAllMatches(new Object[]{pM}).collect(Collectors.toSet());
+    }
+    
+    /**
+     * Returns a stream of all matches of the pattern that conform to the given fixed values of some parameters.
+     * </p>
+     * <strong>NOTE</strong>: It is important not to modify the source model while the stream is being processed.
+     * If the match set of the pattern changes during processing, the contents of the stream is <strong>undefined</strong>.
+     * In such cases, either rely on {@link #getAllMatches()} or collect the results of the stream in end-user code.
+     * @param pM the fixed value of pattern parameter m, or null if not bound.
+     * @return a stream of matches represented as a Match object.
+     * 
+     */
+    public Stream<MemberIsItsOwnParent.Match> streamAllMatches(final Member pM) {
+      return rawStreamAllMatches(new Object[]{pM});
+    }
+    
+    /**
+     * Returns an arbitrarily chosen match of the pattern that conforms to the given fixed values of some parameters.
+     * Neither determinism nor randomness of selection is guaranteed.
+     * @param pM the fixed value of pattern parameter m, or null if not bound.
+     * @return a match represented as a Match object, or null if no match is found.
+     * 
+     */
+    public Optional<MemberIsItsOwnParent.Match> getOneArbitraryMatch(final Member pM) {
+      return rawGetOneArbitraryMatch(new Object[]{pM});
+    }
+    
+    /**
+     * Indicates whether the given combination of specified pattern parameters constitute a valid pattern match,
+     * under any possible substitution of the unspecified parameters (if any).
+     * @param pM the fixed value of pattern parameter m, or null if not bound.
+     * @return true if the input is a valid (partial) match of the pattern.
+     * 
+     */
+    public boolean hasMatch(final Member pM) {
+      return rawHasMatch(new Object[]{pM});
+    }
+    
+    /**
+     * Returns the number of all matches of the pattern that conform to the given fixed values of some parameters.
+     * @param pM the fixed value of pattern parameter m, or null if not bound.
+     * @return the number of pattern matches found.
+     * 
+     */
+    public int countMatches(final Member pM) {
+      return rawCountMatches(new Object[]{pM});
+    }
+    
+    /**
+     * Executes the given processor on an arbitrarily chosen match of the pattern that conforms to the given fixed values of some parameters.
+     * Neither determinism nor randomness of selection is guaranteed.
+     * @param pM the fixed value of pattern parameter m, or null if not bound.
+     * @param processor the action that will process the selected match.
+     * @return true if the pattern has at least one match with the given parameter values, false if the processor was not invoked
+     * 
+     */
+    public boolean forOneArbitraryMatch(final Member pM, final Consumer<? super MemberIsItsOwnParent.Match> processor) {
+      return rawForOneArbitraryMatch(new Object[]{pM}, processor);
+    }
+    
+    /**
+     * Returns a new (partial) match.
+     * This can be used e.g. to call the matcher with a partial match.
+     * <p>The returned match will be immutable. Use {@link #newEmptyMatch()} to obtain a mutable match object.
+     * @param pM the fixed value of pattern parameter m, or null if not bound.
+     * @return the (partial) match object.
+     * 
+     */
+    public MemberIsItsOwnParent.Match newMatch(final Member pM) {
+      return MemberIsItsOwnParent.Match.newMatch(pM);
+    }
+    
+    /**
+     * Retrieve the set of values that occur in matches for m.
+     * @return the Set of all values or empty set if there are no matches
+     * 
+     */
+    protected Stream<Member> rawStreamAllValuesOfm(final Object[] parameters) {
+      return rawStreamAllValues(POSITION_M, parameters).map(Member.class::cast);
+    }
+    
+    /**
+     * Retrieve the set of values that occur in matches for m.
+     * @return the Set of all values or empty set if there are no matches
+     * 
+     */
+    public Set<Member> getAllValuesOfm() {
+      return rawStreamAllValuesOfm(emptyArray()).collect(Collectors.toSet());
+    }
+    
+    /**
+     * Retrieve the set of values that occur in matches for m.
+     * @return the Set of all values or empty set if there are no matches
+     * 
+     */
+    public Stream<Member> streamAllValuesOfm() {
+      return rawStreamAllValuesOfm(emptyArray());
+    }
+    
+    @Override
+    protected MemberIsItsOwnParent.Match tupleToMatch(final Tuple t) {
+      try {
+          return MemberIsItsOwnParent.Match.newMatch((Member) t.get(POSITION_M));
+      } catch(ClassCastException e) {
+          LOGGER.error("Element(s) in tuple not properly typed!",e);
+          return null;
+      }
+    }
+    
+    @Override
+    protected MemberIsItsOwnParent.Match arrayToMatch(final Object[] match) {
+      try {
+          return MemberIsItsOwnParent.Match.newMatch((Member) match[POSITION_M]);
+      } catch(ClassCastException e) {
+          LOGGER.error("Element(s) in array not properly typed!",e);
+          return null;
+      }
+    }
+    
+    @Override
+    protected MemberIsItsOwnParent.Match arrayToMatchMutable(final Object[] match) {
+      try {
+          return MemberIsItsOwnParent.Match.newMutableMatch((Member) match[POSITION_M]);
+      } catch(ClassCastException e) {
+          LOGGER.error("Element(s) in array not properly typed!",e);
+          return null;
+      }
+    }
+    
+    /**
+     * @return the singleton instance of the query specification of this pattern
+     * @throws ViatraQueryRuntimeException if the pattern definition could not be loaded
+     * 
+     */
+    public static IQuerySpecification<MemberIsItsOwnParent.Matcher> querySpecification() {
+      return MemberIsItsOwnParent.instance();
+    }
+  }
+  
+  private MemberIsItsOwnParent() {
+    super(GeneratedPQuery.INSTANCE);
+  }
+  
+  /**
+   * @return the singleton instance of the query specification
+   * @throws ViatraQueryRuntimeException if the pattern definition could not be loaded
+   * 
+   */
+  public static MemberIsItsOwnParent instance() {
+    try{
+        return LazyHolder.INSTANCE;
+    } catch (ExceptionInInitializerError err) {
+        throw processInitializerError(err);
+    }
+  }
+  
+  @Override
+  protected MemberIsItsOwnParent.Matcher instantiate(final ViatraQueryEngine engine) {
+    return MemberIsItsOwnParent.Matcher.on(engine);
+  }
+  
+  @Override
+  public MemberIsItsOwnParent.Matcher instantiate() {
+    return MemberIsItsOwnParent.Matcher.create();
+  }
+  
+  @Override
+  public MemberIsItsOwnParent.Match newEmptyMatch() {
+    return MemberIsItsOwnParent.Match.newEmptyMatch();
+  }
+  
+  @Override
+  public MemberIsItsOwnParent.Match newMatch(final Object... parameters) {
+    return MemberIsItsOwnParent.Match.newMatch((familytree.Member) parameters[0]);
+  }
+  
+  /**
+   * Inner class allowing the singleton instance of {@link MemberIsItsOwnParent} to be created 
+   *     <b>not</b> at the class load time of the outer class, 
+   *     but rather at the first call to {@link MemberIsItsOwnParent#instance()}.
+   * 
+   * <p> This workaround is required e.g. to support recursion.
+   * 
+   */
+  private static class LazyHolder {
+    private static final MemberIsItsOwnParent INSTANCE = new MemberIsItsOwnParent();
+    
+    /**
+     * Statically initializes the query specification <b>after</b> the field {@link #INSTANCE} is assigned.
+     * This initialization order is required to support indirect recursion.
+     * 
+     * <p> The static initializer is defined using a helper field to work around limitations of the code generator.
+     * 
+     */
+    private static final Object STATIC_INITIALIZER = ensureInitialized();
+    
+    public static Object ensureInitialized() {
+      INSTANCE.ensureInitializedInternal();
+      return null;
+    }
+  }
+  
+  private static class GeneratedPQuery extends BaseGeneratedEMFPQuery {
+    private static final MemberIsItsOwnParent.GeneratedPQuery INSTANCE = new GeneratedPQuery();
+    
+    private final PParameter parameter_m = new PParameter("m", "familytree.Member", new EClassTransitiveInstancesKey((EClass)getClassifierLiteralSafe("http://www.example.org/familytree", "Member")), PParameterDirection.INOUT);
+    
+    private final List<PParameter> parameters = Arrays.asList(parameter_m);
+    
+    private GeneratedPQuery() {
+      super(PVisibility.PUBLIC);
+    }
+    
+    @Override
+    public String getFullyQualifiedName() {
+      return "queries.memberIsItsOwnParent";
+    }
+    
+    @Override
+    public List<String> getParameterNames() {
+      return Arrays.asList("m");
+    }
+    
+    @Override
+    public List<PParameter> getParameters() {
+      return parameters;
+    }
+    
+    @Override
+    public Set<PBody> doGetContainedBodies() {
+      setEvaluationHints(new QueryEvaluationHint(null, QueryEvaluationHint.BackendRequirement.UNSPECIFIED));
+      Set<PBody> bodies = new LinkedHashSet<>();
+      {
+          PBody body = new PBody(this);
+          PVariable var_m = body.getOrCreateVariableByName("m");
+          PVariable var___0_ = body.getOrCreateVariableByName("_<0>");
+          PVariable var_p = body.getOrCreateVariableByName("p");
+          new TypeConstraint(body, Tuples.flatTupleOf(var_m), new EClassTransitiveInstancesKey((EClass)getClassifierLiteral("http://www.example.org/familytree", "Member")));
+          body.setSymbolicParameters(Arrays.<ExportedParameter>asList(
+             new ExportedParameter(body, var_m, parameter_m)
+          ));
+          //    FamilyTree.members(_, m)
+          new TypeConstraint(body, Tuples.flatTupleOf(var___0_), new EClassTransitiveInstancesKey((EClass)getClassifierLiteral("http://www.example.org/familytree", "FamilyTree")));
+          PVariable var__virtual_0_ = body.getOrCreateVariableByName(".virtual{0}");
+          new TypeConstraint(body, Tuples.flatTupleOf(var___0_, var__virtual_0_), new EStructuralFeatureInstancesKey(getFeatureLiteral("http://www.example.org/familytree", "FamilyTree", "members")));
+          new TypeConstraint(body, Tuples.flatTupleOf(var__virtual_0_), new EClassTransitiveInstancesKey((EClass)getClassifierLiteral("http://www.example.org/familytree", "Member")));
+          new Equality(body, var__virtual_0_, var_m);
+          //    Member.parents(m, p)
+          new TypeConstraint(body, Tuples.flatTupleOf(var_m), new EClassTransitiveInstancesKey((EClass)getClassifierLiteral("http://www.example.org/familytree", "Member")));
+          PVariable var__virtual_1_ = body.getOrCreateVariableByName(".virtual{1}");
+          new TypeConstraint(body, Tuples.flatTupleOf(var_m, var__virtual_1_), new EStructuralFeatureInstancesKey(getFeatureLiteral("http://www.example.org/familytree", "Member", "parents")));
+          new TypeConstraint(body, Tuples.flatTupleOf(var__virtual_1_), new EClassTransitiveInstancesKey((EClass)getClassifierLiteral("http://www.example.org/familytree", "Member")));
+          new Equality(body, var__virtual_1_, var_p);
+          //    m == p
+          new Equality(body, var_m, var_p);
+          bodies.add(body);
+      }
+      {
+          PAnnotation annotation = new PAnnotation("Constraint");
+          annotation.addAttribute("message", "memberIsItsOwnParent");
+          annotation.addAttribute("severity", "error");
+          annotation.addAttribute("key", Arrays.asList(new Object[] {
+                              new ParameterReference("m")
+                              }));
+          addAnnotation(annotation);
+      }
+      return bodies;
+    }
+  }
+}
diff --git a/Tests/MODELS2020-CaseStudies/case.study.familyTree.run/src-gen/queries/NegativeAge.java b/Tests/MODELS2020-CaseStudies/case.study.familyTree.run/src-gen/queries/NegativeAge.java
new file mode 100644
index 00000000..44ae6496
--- /dev/null
+++ b/Tests/MODELS2020-CaseStudies/case.study.familyTree.run/src-gen/queries/NegativeAge.java
@@ -0,0 +1,593 @@
+/**
+ * Generated from platform:/resource/case.study.familyTree.run/src/queries/familyTreeConstraints.vql
+ */
+package queries;
+
+import familytree.Member;
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.LinkedHashSet;
+import java.util.List;
+import java.util.Objects;
+import java.util.Optional;
+import java.util.Set;
+import java.util.function.Consumer;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
+import org.apache.log4j.Logger;
+import org.eclipse.emf.ecore.EClass;
+import org.eclipse.emf.ecore.EDataType;
+import org.eclipse.viatra.query.runtime.api.IPatternMatch;
+import org.eclipse.viatra.query.runtime.api.IQuerySpecification;
+import org.eclipse.viatra.query.runtime.api.ViatraQueryEngine;
+import org.eclipse.viatra.query.runtime.api.impl.BaseGeneratedEMFPQuery;
+import org.eclipse.viatra.query.runtime.api.impl.BaseGeneratedEMFQuerySpecification;
+import org.eclipse.viatra.query.runtime.api.impl.BaseMatcher;
+import org.eclipse.viatra.query.runtime.api.impl.BasePatternMatch;
+import org.eclipse.viatra.query.runtime.emf.types.EClassTransitiveInstancesKey;
+import org.eclipse.viatra.query.runtime.emf.types.EDataTypeInSlotsKey;
+import org.eclipse.viatra.query.runtime.emf.types.EStructuralFeatureInstancesKey;
+import org.eclipse.viatra.query.runtime.matchers.backend.QueryEvaluationHint;
+import org.eclipse.viatra.query.runtime.matchers.psystem.IExpressionEvaluator;
+import org.eclipse.viatra.query.runtime.matchers.psystem.IValueProvider;
+import org.eclipse.viatra.query.runtime.matchers.psystem.PBody;
+import org.eclipse.viatra.query.runtime.matchers.psystem.PVariable;
+import org.eclipse.viatra.query.runtime.matchers.psystem.annotations.PAnnotation;
+import org.eclipse.viatra.query.runtime.matchers.psystem.annotations.ParameterReference;
+import org.eclipse.viatra.query.runtime.matchers.psystem.basicdeferred.Equality;
+import org.eclipse.viatra.query.runtime.matchers.psystem.basicdeferred.ExportedParameter;
+import org.eclipse.viatra.query.runtime.matchers.psystem.basicdeferred.ExpressionEvaluation;
+import org.eclipse.viatra.query.runtime.matchers.psystem.basicenumerables.TypeConstraint;
+import org.eclipse.viatra.query.runtime.matchers.psystem.queries.PParameter;
+import org.eclipse.viatra.query.runtime.matchers.psystem.queries.PParameterDirection;
+import org.eclipse.viatra.query.runtime.matchers.psystem.queries.PVisibility;
+import org.eclipse.viatra.query.runtime.matchers.tuple.Tuple;
+import org.eclipse.viatra.query.runtime.matchers.tuple.Tuples;
+import org.eclipse.viatra.query.runtime.util.ViatraQueryLoggingUtil;
+
+/**
+ * A pattern-specific query specification that can instantiate Matcher in a type-safe way.
+ * 
+ * <p>Original source:
+ *         <code><pre>
+ *         {@literal @}Constraint(message="negativeAge", severity="error",key={m})
+ *         pattern negativeAge(m: Member) {
+ *              Member.age(m,mage);
+ *              check(mage{@literal <}0);
+ *         }
+ * </pre></code>
+ * 
+ * @see Matcher
+ * @see Match
+ * 
+ */
+@SuppressWarnings("all")
+public final class NegativeAge extends BaseGeneratedEMFQuerySpecification<NegativeAge.Matcher> {
+  /**
+   * Pattern-specific match representation of the queries.negativeAge pattern,
+   * to be used in conjunction with {@link Matcher}.
+   * 
+   * <p>Class fields correspond to parameters of the pattern. Fields with value null are considered unassigned.
+   * Each instance is a (possibly partial) substitution of pattern parameters,
+   * usable to represent a match of the pattern in the result of a query,
+   * or to specify the bound (fixed) input parameters when issuing a query.
+   * 
+   * @see Matcher
+   * 
+   */
+  public static abstract class Match extends BasePatternMatch {
+    private Member fM;
+    
+    private static List<String> parameterNames = makeImmutableList("m");
+    
+    private Match(final Member pM) {
+      this.fM = pM;
+    }
+    
+    @Override
+    public Object get(final String parameterName) {
+      switch(parameterName) {
+          case "m": return this.fM;
+          default: return null;
+      }
+    }
+    
+    @Override
+    public Object get(final int index) {
+      switch(index) {
+          case 0: return this.fM;
+          default: return null;
+      }
+    }
+    
+    public Member getM() {
+      return this.fM;
+    }
+    
+    @Override
+    public boolean set(final String parameterName, final Object newValue) {
+      if (!isMutable()) throw new java.lang.UnsupportedOperationException();
+      if ("m".equals(parameterName) ) {
+          this.fM = (Member) newValue;
+          return true;
+      }
+      return false;
+    }
+    
+    public void setM(final Member pM) {
+      if (!isMutable()) throw new java.lang.UnsupportedOperationException();
+      this.fM = pM;
+    }
+    
+    @Override
+    public String patternName() {
+      return "queries.negativeAge";
+    }
+    
+    @Override
+    public List<String> parameterNames() {
+      return NegativeAge.Match.parameterNames;
+    }
+    
+    @Override
+    public Object[] toArray() {
+      return new Object[]{fM};
+    }
+    
+    @Override
+    public NegativeAge.Match toImmutable() {
+      return isMutable() ? newMatch(fM) : this;
+    }
+    
+    @Override
+    public String prettyPrint() {
+      StringBuilder result = new StringBuilder();
+      result.append("\"m\"=" + prettyPrintValue(fM));
+      return result.toString();
+    }
+    
+    @Override
+    public int hashCode() {
+      return Objects.hash(fM);
+    }
+    
+    @Override
+    public boolean equals(final Object obj) {
+      if (this == obj)
+          return true;
+      if (obj == null) {
+          return false;
+      }
+      if ((obj instanceof NegativeAge.Match)) {
+          NegativeAge.Match other = (NegativeAge.Match) obj;
+          return Objects.equals(fM, other.fM);
+      } else {
+          // this should be infrequent
+          if (!(obj instanceof IPatternMatch)) {
+              return false;
+          }
+          IPatternMatch otherSig  = (IPatternMatch) obj;
+          return Objects.equals(specification(), otherSig.specification()) && Arrays.deepEquals(toArray(), otherSig.toArray());
+      }
+    }
+    
+    @Override
+    public NegativeAge specification() {
+      return NegativeAge.instance();
+    }
+    
+    /**
+     * Returns an empty, mutable match.
+     * Fields of the mutable match can be filled to create a partial match, usable as matcher input.
+     * 
+     * @return the empty match.
+     * 
+     */
+    public static NegativeAge.Match newEmptyMatch() {
+      return new Mutable(null);
+    }
+    
+    /**
+     * Returns a mutable (partial) match.
+     * Fields of the mutable match can be filled to create a partial match, usable as matcher input.
+     * 
+     * @param pM the fixed value of pattern parameter m, or null if not bound.
+     * @return the new, mutable (partial) match object.
+     * 
+     */
+    public static NegativeAge.Match newMutableMatch(final Member pM) {
+      return new Mutable(pM);
+    }
+    
+    /**
+     * Returns a new (partial) match.
+     * This can be used e.g. to call the matcher with a partial match.
+     * <p>The returned match will be immutable. Use {@link #newEmptyMatch()} to obtain a mutable match object.
+     * @param pM the fixed value of pattern parameter m, or null if not bound.
+     * @return the (partial) match object.
+     * 
+     */
+    public static NegativeAge.Match newMatch(final Member pM) {
+      return new Immutable(pM);
+    }
+    
+    private static final class Mutable extends NegativeAge.Match {
+      Mutable(final Member pM) {
+        super(pM);
+      }
+      
+      @Override
+      public boolean isMutable() {
+        return true;
+      }
+    }
+    
+    private static final class Immutable extends NegativeAge.Match {
+      Immutable(final Member pM) {
+        super(pM);
+      }
+      
+      @Override
+      public boolean isMutable() {
+        return false;
+      }
+    }
+  }
+  
+  /**
+   * Generated pattern matcher API of the queries.negativeAge pattern,
+   * providing pattern-specific query methods.
+   * 
+   * <p>Use the pattern matcher on a given model via {@link #on(ViatraQueryEngine)},
+   * e.g. in conjunction with {@link ViatraQueryEngine#on(QueryScope)}.
+   * 
+   * <p>Matches of the pattern will be represented as {@link Match}.
+   * 
+   * <p>Original source:
+   * <code><pre>
+   * {@literal @}Constraint(message="negativeAge", severity="error",key={m})
+   * pattern negativeAge(m: Member) {
+   *    Member.age(m,mage);
+   *    check(mage{@literal <}0);
+   * }
+   * </pre></code>
+   * 
+   * @see Match
+   * @see NegativeAge
+   * 
+   */
+  public static class Matcher extends BaseMatcher<NegativeAge.Match> {
+    /**
+     * Initializes the pattern matcher within an existing VIATRA Query engine.
+     * If the pattern matcher is already constructed in the engine, only a light-weight reference is returned.
+     * 
+     * @param engine the existing VIATRA Query engine in which this matcher will be created.
+     * @throws ViatraQueryRuntimeException if an error occurs during pattern matcher creation
+     * 
+     */
+    public static NegativeAge.Matcher on(final ViatraQueryEngine engine) {
+      // check if matcher already exists
+      Matcher matcher = engine.getExistingMatcher(querySpecification());
+      if (matcher == null) {
+          matcher = (Matcher)engine.getMatcher(querySpecification());
+      }
+      return matcher;
+    }
+    
+    /**
+     * @throws ViatraQueryRuntimeException if an error occurs during pattern matcher creation
+     * @return an initialized matcher
+     * @noreference This method is for internal matcher initialization by the framework, do not call it manually.
+     * 
+     */
+    public static NegativeAge.Matcher create() {
+      return new Matcher();
+    }
+    
+    private static final int POSITION_M = 0;
+    
+    private static final Logger LOGGER = ViatraQueryLoggingUtil.getLogger(NegativeAge.Matcher.class);
+    
+    /**
+     * Initializes the pattern matcher within an existing VIATRA Query engine.
+     * If the pattern matcher is already constructed in the engine, only a light-weight reference is returned.
+     * 
+     * @param engine the existing VIATRA Query engine in which this matcher will be created.
+     * @throws ViatraQueryRuntimeException if an error occurs during pattern matcher creation
+     * 
+     */
+    private Matcher() {
+      super(querySpecification());
+    }
+    
+    /**
+     * Returns the set of all matches of the pattern that conform to the given fixed values of some parameters.
+     * @param pM the fixed value of pattern parameter m, or null if not bound.
+     * @return matches represented as a Match object.
+     * 
+     */
+    public Collection<NegativeAge.Match> getAllMatches(final Member pM) {
+      return rawStreamAllMatches(new Object[]{pM}).collect(Collectors.toSet());
+    }
+    
+    /**
+     * Returns a stream of all matches of the pattern that conform to the given fixed values of some parameters.
+     * </p>
+     * <strong>NOTE</strong>: It is important not to modify the source model while the stream is being processed.
+     * If the match set of the pattern changes during processing, the contents of the stream is <strong>undefined</strong>.
+     * In such cases, either rely on {@link #getAllMatches()} or collect the results of the stream in end-user code.
+     * @param pM the fixed value of pattern parameter m, or null if not bound.
+     * @return a stream of matches represented as a Match object.
+     * 
+     */
+    public Stream<NegativeAge.Match> streamAllMatches(final Member pM) {
+      return rawStreamAllMatches(new Object[]{pM});
+    }
+    
+    /**
+     * Returns an arbitrarily chosen match of the pattern that conforms to the given fixed values of some parameters.
+     * Neither determinism nor randomness of selection is guaranteed.
+     * @param pM the fixed value of pattern parameter m, or null if not bound.
+     * @return a match represented as a Match object, or null if no match is found.
+     * 
+     */
+    public Optional<NegativeAge.Match> getOneArbitraryMatch(final Member pM) {
+      return rawGetOneArbitraryMatch(new Object[]{pM});
+    }
+    
+    /**
+     * Indicates whether the given combination of specified pattern parameters constitute a valid pattern match,
+     * under any possible substitution of the unspecified parameters (if any).
+     * @param pM the fixed value of pattern parameter m, or null if not bound.
+     * @return true if the input is a valid (partial) match of the pattern.
+     * 
+     */
+    public boolean hasMatch(final Member pM) {
+      return rawHasMatch(new Object[]{pM});
+    }
+    
+    /**
+     * Returns the number of all matches of the pattern that conform to the given fixed values of some parameters.
+     * @param pM the fixed value of pattern parameter m, or null if not bound.
+     * @return the number of pattern matches found.
+     * 
+     */
+    public int countMatches(final Member pM) {
+      return rawCountMatches(new Object[]{pM});
+    }
+    
+    /**
+     * Executes the given processor on an arbitrarily chosen match of the pattern that conforms to the given fixed values of some parameters.
+     * Neither determinism nor randomness of selection is guaranteed.
+     * @param pM the fixed value of pattern parameter m, or null if not bound.
+     * @param processor the action that will process the selected match.
+     * @return true if the pattern has at least one match with the given parameter values, false if the processor was not invoked
+     * 
+     */
+    public boolean forOneArbitraryMatch(final Member pM, final Consumer<? super NegativeAge.Match> processor) {
+      return rawForOneArbitraryMatch(new Object[]{pM}, processor);
+    }
+    
+    /**
+     * Returns a new (partial) match.
+     * This can be used e.g. to call the matcher with a partial match.
+     * <p>The returned match will be immutable. Use {@link #newEmptyMatch()} to obtain a mutable match object.
+     * @param pM the fixed value of pattern parameter m, or null if not bound.
+     * @return the (partial) match object.
+     * 
+     */
+    public NegativeAge.Match newMatch(final Member pM) {
+      return NegativeAge.Match.newMatch(pM);
+    }
+    
+    /**
+     * Retrieve the set of values that occur in matches for m.
+     * @return the Set of all values or empty set if there are no matches
+     * 
+     */
+    protected Stream<Member> rawStreamAllValuesOfm(final Object[] parameters) {
+      return rawStreamAllValues(POSITION_M, parameters).map(Member.class::cast);
+    }
+    
+    /**
+     * Retrieve the set of values that occur in matches for m.
+     * @return the Set of all values or empty set if there are no matches
+     * 
+     */
+    public Set<Member> getAllValuesOfm() {
+      return rawStreamAllValuesOfm(emptyArray()).collect(Collectors.toSet());
+    }
+    
+    /**
+     * Retrieve the set of values that occur in matches for m.
+     * @return the Set of all values or empty set if there are no matches
+     * 
+     */
+    public Stream<Member> streamAllValuesOfm() {
+      return rawStreamAllValuesOfm(emptyArray());
+    }
+    
+    @Override
+    protected NegativeAge.Match tupleToMatch(final Tuple t) {
+      try {
+          return NegativeAge.Match.newMatch((Member) t.get(POSITION_M));
+      } catch(ClassCastException e) {
+          LOGGER.error("Element(s) in tuple not properly typed!",e);
+          return null;
+      }
+    }
+    
+    @Override
+    protected NegativeAge.Match arrayToMatch(final Object[] match) {
+      try {
+          return NegativeAge.Match.newMatch((Member) match[POSITION_M]);
+      } catch(ClassCastException e) {
+          LOGGER.error("Element(s) in array not properly typed!",e);
+          return null;
+      }
+    }
+    
+    @Override
+    protected NegativeAge.Match arrayToMatchMutable(final Object[] match) {
+      try {
+          return NegativeAge.Match.newMutableMatch((Member) match[POSITION_M]);
+      } catch(ClassCastException e) {
+          LOGGER.error("Element(s) in array not properly typed!",e);
+          return null;
+      }
+    }
+    
+    /**
+     * @return the singleton instance of the query specification of this pattern
+     * @throws ViatraQueryRuntimeException if the pattern definition could not be loaded
+     * 
+     */
+    public static IQuerySpecification<NegativeAge.Matcher> querySpecification() {
+      return NegativeAge.instance();
+    }
+  }
+  
+  private NegativeAge() {
+    super(GeneratedPQuery.INSTANCE);
+  }
+  
+  /**
+   * @return the singleton instance of the query specification
+   * @throws ViatraQueryRuntimeException if the pattern definition could not be loaded
+   * 
+   */
+  public static NegativeAge instance() {
+    try{
+        return LazyHolder.INSTANCE;
+    } catch (ExceptionInInitializerError err) {
+        throw processInitializerError(err);
+    }
+  }
+  
+  @Override
+  protected NegativeAge.Matcher instantiate(final ViatraQueryEngine engine) {
+    return NegativeAge.Matcher.on(engine);
+  }
+  
+  @Override
+  public NegativeAge.Matcher instantiate() {
+    return NegativeAge.Matcher.create();
+  }
+  
+  @Override
+  public NegativeAge.Match newEmptyMatch() {
+    return NegativeAge.Match.newEmptyMatch();
+  }
+  
+  @Override
+  public NegativeAge.Match newMatch(final Object... parameters) {
+    return NegativeAge.Match.newMatch((familytree.Member) parameters[0]);
+  }
+  
+  /**
+   * Inner class allowing the singleton instance of {@link NegativeAge} to be created 
+   *     <b>not</b> at the class load time of the outer class, 
+   *     but rather at the first call to {@link NegativeAge#instance()}.
+   * 
+   * <p> This workaround is required e.g. to support recursion.
+   * 
+   */
+  private static class LazyHolder {
+    private static final NegativeAge INSTANCE = new NegativeAge();
+    
+    /**
+     * Statically initializes the query specification <b>after</b> the field {@link #INSTANCE} is assigned.
+     * This initialization order is required to support indirect recursion.
+     * 
+     * <p> The static initializer is defined using a helper field to work around limitations of the code generator.
+     * 
+     */
+    private static final Object STATIC_INITIALIZER = ensureInitialized();
+    
+    public static Object ensureInitialized() {
+      INSTANCE.ensureInitializedInternal();
+      return null;
+    }
+  }
+  
+  private static class GeneratedPQuery extends BaseGeneratedEMFPQuery {
+    private static final NegativeAge.GeneratedPQuery INSTANCE = new GeneratedPQuery();
+    
+    private final PParameter parameter_m = new PParameter("m", "familytree.Member", new EClassTransitiveInstancesKey((EClass)getClassifierLiteralSafe("http://www.example.org/familytree", "Member")), PParameterDirection.INOUT);
+    
+    private final List<PParameter> parameters = Arrays.asList(parameter_m);
+    
+    private GeneratedPQuery() {
+      super(PVisibility.PUBLIC);
+    }
+    
+    @Override
+    public String getFullyQualifiedName() {
+      return "queries.negativeAge";
+    }
+    
+    @Override
+    public List<String> getParameterNames() {
+      return Arrays.asList("m");
+    }
+    
+    @Override
+    public List<PParameter> getParameters() {
+      return parameters;
+    }
+    
+    @Override
+    public Set<PBody> doGetContainedBodies() {
+      setEvaluationHints(new QueryEvaluationHint(null, QueryEvaluationHint.BackendRequirement.UNSPECIFIED));
+      Set<PBody> bodies = new LinkedHashSet<>();
+      {
+          PBody body = new PBody(this);
+          PVariable var_m = body.getOrCreateVariableByName("m");
+          PVariable var_mage = body.getOrCreateVariableByName("mage");
+          new TypeConstraint(body, Tuples.flatTupleOf(var_m), new EClassTransitiveInstancesKey((EClass)getClassifierLiteral("http://www.example.org/familytree", "Member")));
+          body.setSymbolicParameters(Arrays.<ExportedParameter>asList(
+             new ExportedParameter(body, var_m, parameter_m)
+          ));
+          //    Member.age(m,mage)
+          new TypeConstraint(body, Tuples.flatTupleOf(var_m), new EClassTransitiveInstancesKey((EClass)getClassifierLiteral("http://www.example.org/familytree", "Member")));
+          PVariable var__virtual_0_ = body.getOrCreateVariableByName(".virtual{0}");
+          new TypeConstraint(body, Tuples.flatTupleOf(var_m, var__virtual_0_), new EStructuralFeatureInstancesKey(getFeatureLiteral("http://www.example.org/familytree", "Member", "age")));
+          new TypeConstraint(body, Tuples.flatTupleOf(var__virtual_0_), new EDataTypeInSlotsKey((EDataType)getClassifierLiteral("http://www.eclipse.org/emf/2002/Ecore", "EInt")));
+          new Equality(body, var__virtual_0_, var_mage);
+          //    check(mage<0)
+          new ExpressionEvaluation(body, new IExpressionEvaluator() {
+          
+              @Override
+              public String getShortDescription() {
+                  return "Expression evaluation from pattern negativeAge";
+              }
+              
+              @Override
+              public Iterable<String> getInputParameterNames() {
+                  return Arrays.asList("mage");}
+          
+              @Override
+              public Object evaluateExpression(IValueProvider provider) throws Exception {
+                  Integer mage = (Integer) provider.getValue("mage");
+                  return evaluateExpression_1_1(mage);
+              }
+          },  null); 
+          bodies.add(body);
+      }
+      {
+          PAnnotation annotation = new PAnnotation("Constraint");
+          annotation.addAttribute("message", "negativeAge");
+          annotation.addAttribute("severity", "error");
+          annotation.addAttribute("key", Arrays.asList(new Object[] {
+                              new ParameterReference("m")
+                              }));
+          addAnnotation(annotation);
+      }
+      return bodies;
+    }
+  }
+  
+  private static boolean evaluateExpression_1_1(final Integer mage) {
+    return ((mage).intValue() < 0);
+  }
+}
diff --git a/Tests/MODELS2020-CaseStudies/case.study.familyTree.run/src-gen/queries/ParentTooYoung.java b/Tests/MODELS2020-CaseStudies/case.study.familyTree.run/src-gen/queries/ParentTooYoung.java
new file mode 100644
index 00000000..5ed9df5e
--- /dev/null
+++ b/Tests/MODELS2020-CaseStudies/case.study.familyTree.run/src-gen/queries/ParentTooYoung.java
@@ -0,0 +1,775 @@
+/**
+ * Generated from platform:/resource/case.study.familyTree.run/src/queries/familyTreeConstraints.vql
+ */
+package queries;
+
+import familytree.Member;
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.LinkedHashSet;
+import java.util.List;
+import java.util.Objects;
+import java.util.Optional;
+import java.util.Set;
+import java.util.function.Consumer;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
+import org.apache.log4j.Logger;
+import org.eclipse.emf.ecore.EClass;
+import org.eclipse.emf.ecore.EDataType;
+import org.eclipse.viatra.query.runtime.api.IPatternMatch;
+import org.eclipse.viatra.query.runtime.api.IQuerySpecification;
+import org.eclipse.viatra.query.runtime.api.ViatraQueryEngine;
+import org.eclipse.viatra.query.runtime.api.impl.BaseGeneratedEMFPQuery;
+import org.eclipse.viatra.query.runtime.api.impl.BaseGeneratedEMFQuerySpecification;
+import org.eclipse.viatra.query.runtime.api.impl.BaseMatcher;
+import org.eclipse.viatra.query.runtime.api.impl.BasePatternMatch;
+import org.eclipse.viatra.query.runtime.emf.types.EClassTransitiveInstancesKey;
+import org.eclipse.viatra.query.runtime.emf.types.EDataTypeInSlotsKey;
+import org.eclipse.viatra.query.runtime.emf.types.EStructuralFeatureInstancesKey;
+import org.eclipse.viatra.query.runtime.matchers.backend.QueryEvaluationHint;
+import org.eclipse.viatra.query.runtime.matchers.psystem.IExpressionEvaluator;
+import org.eclipse.viatra.query.runtime.matchers.psystem.IValueProvider;
+import org.eclipse.viatra.query.runtime.matchers.psystem.PBody;
+import org.eclipse.viatra.query.runtime.matchers.psystem.PVariable;
+import org.eclipse.viatra.query.runtime.matchers.psystem.annotations.PAnnotation;
+import org.eclipse.viatra.query.runtime.matchers.psystem.annotations.ParameterReference;
+import org.eclipse.viatra.query.runtime.matchers.psystem.basicdeferred.Equality;
+import org.eclipse.viatra.query.runtime.matchers.psystem.basicdeferred.ExportedParameter;
+import org.eclipse.viatra.query.runtime.matchers.psystem.basicdeferred.ExpressionEvaluation;
+import org.eclipse.viatra.query.runtime.matchers.psystem.basicenumerables.TypeConstraint;
+import org.eclipse.viatra.query.runtime.matchers.psystem.queries.PParameter;
+import org.eclipse.viatra.query.runtime.matchers.psystem.queries.PParameterDirection;
+import org.eclipse.viatra.query.runtime.matchers.psystem.queries.PVisibility;
+import org.eclipse.viatra.query.runtime.matchers.tuple.Tuple;
+import org.eclipse.viatra.query.runtime.matchers.tuple.Tuples;
+import org.eclipse.viatra.query.runtime.util.ViatraQueryLoggingUtil;
+
+/**
+ * A pattern-specific query specification that can instantiate Matcher in a type-safe way.
+ * 
+ * <p>Original source:
+ *         <code><pre>
+ *         {@literal @}Constraint(message="parentTooYoung", severity="error", key={c, p})
+ *         pattern parentTooYoung(c: Member, p: Member) = {
+ *              FamilyTree.members(_, c);
+ *              Member.parents(c, p);
+ *              Member.age(c, cAge);
+ *              Member.age(p, pAge);
+ *              check (pAge {@literal <}= (cAge + 12));
+ *         }
+ * </pre></code>
+ * 
+ * @see Matcher
+ * @see Match
+ * 
+ */
+@SuppressWarnings("all")
+public final class ParentTooYoung extends BaseGeneratedEMFQuerySpecification<ParentTooYoung.Matcher> {
+  /**
+   * Pattern-specific match representation of the queries.parentTooYoung pattern,
+   * to be used in conjunction with {@link Matcher}.
+   * 
+   * <p>Class fields correspond to parameters of the pattern. Fields with value null are considered unassigned.
+   * Each instance is a (possibly partial) substitution of pattern parameters,
+   * usable to represent a match of the pattern in the result of a query,
+   * or to specify the bound (fixed) input parameters when issuing a query.
+   * 
+   * @see Matcher
+   * 
+   */
+  public static abstract class Match extends BasePatternMatch {
+    private Member fC;
+    
+    private Member fP;
+    
+    private static List<String> parameterNames = makeImmutableList("c", "p");
+    
+    private Match(final Member pC, final Member pP) {
+      this.fC = pC;
+      this.fP = pP;
+    }
+    
+    @Override
+    public Object get(final String parameterName) {
+      switch(parameterName) {
+          case "c": return this.fC;
+          case "p": return this.fP;
+          default: return null;
+      }
+    }
+    
+    @Override
+    public Object get(final int index) {
+      switch(index) {
+          case 0: return this.fC;
+          case 1: return this.fP;
+          default: return null;
+      }
+    }
+    
+    public Member getC() {
+      return this.fC;
+    }
+    
+    public Member getP() {
+      return this.fP;
+    }
+    
+    @Override
+    public boolean set(final String parameterName, final Object newValue) {
+      if (!isMutable()) throw new java.lang.UnsupportedOperationException();
+      if ("c".equals(parameterName) ) {
+          this.fC = (Member) newValue;
+          return true;
+      }
+      if ("p".equals(parameterName) ) {
+          this.fP = (Member) newValue;
+          return true;
+      }
+      return false;
+    }
+    
+    public void setC(final Member pC) {
+      if (!isMutable()) throw new java.lang.UnsupportedOperationException();
+      this.fC = pC;
+    }
+    
+    public void setP(final Member pP) {
+      if (!isMutable()) throw new java.lang.UnsupportedOperationException();
+      this.fP = pP;
+    }
+    
+    @Override
+    public String patternName() {
+      return "queries.parentTooYoung";
+    }
+    
+    @Override
+    public List<String> parameterNames() {
+      return ParentTooYoung.Match.parameterNames;
+    }
+    
+    @Override
+    public Object[] toArray() {
+      return new Object[]{fC, fP};
+    }
+    
+    @Override
+    public ParentTooYoung.Match toImmutable() {
+      return isMutable() ? newMatch(fC, fP) : this;
+    }
+    
+    @Override
+    public String prettyPrint() {
+      StringBuilder result = new StringBuilder();
+      result.append("\"c\"=" + prettyPrintValue(fC) + ", ");
+      result.append("\"p\"=" + prettyPrintValue(fP));
+      return result.toString();
+    }
+    
+    @Override
+    public int hashCode() {
+      return Objects.hash(fC, fP);
+    }
+    
+    @Override
+    public boolean equals(final Object obj) {
+      if (this == obj)
+          return true;
+      if (obj == null) {
+          return false;
+      }
+      if ((obj instanceof ParentTooYoung.Match)) {
+          ParentTooYoung.Match other = (ParentTooYoung.Match) obj;
+          return Objects.equals(fC, other.fC) && Objects.equals(fP, other.fP);
+      } else {
+          // this should be infrequent
+          if (!(obj instanceof IPatternMatch)) {
+              return false;
+          }
+          IPatternMatch otherSig  = (IPatternMatch) obj;
+          return Objects.equals(specification(), otherSig.specification()) && Arrays.deepEquals(toArray(), otherSig.toArray());
+      }
+    }
+    
+    @Override
+    public ParentTooYoung specification() {
+      return ParentTooYoung.instance();
+    }
+    
+    /**
+     * Returns an empty, mutable match.
+     * Fields of the mutable match can be filled to create a partial match, usable as matcher input.
+     * 
+     * @return the empty match.
+     * 
+     */
+    public static ParentTooYoung.Match newEmptyMatch() {
+      return new Mutable(null, null);
+    }
+    
+    /**
+     * Returns a mutable (partial) match.
+     * Fields of the mutable match can be filled to create a partial match, usable as matcher input.
+     * 
+     * @param pC the fixed value of pattern parameter c, or null if not bound.
+     * @param pP the fixed value of pattern parameter p, or null if not bound.
+     * @return the new, mutable (partial) match object.
+     * 
+     */
+    public static ParentTooYoung.Match newMutableMatch(final Member pC, final Member pP) {
+      return new Mutable(pC, pP);
+    }
+    
+    /**
+     * Returns a new (partial) match.
+     * This can be used e.g. to call the matcher with a partial match.
+     * <p>The returned match will be immutable. Use {@link #newEmptyMatch()} to obtain a mutable match object.
+     * @param pC the fixed value of pattern parameter c, or null if not bound.
+     * @param pP the fixed value of pattern parameter p, or null if not bound.
+     * @return the (partial) match object.
+     * 
+     */
+    public static ParentTooYoung.Match newMatch(final Member pC, final Member pP) {
+      return new Immutable(pC, pP);
+    }
+    
+    private static final class Mutable extends ParentTooYoung.Match {
+      Mutable(final Member pC, final Member pP) {
+        super(pC, pP);
+      }
+      
+      @Override
+      public boolean isMutable() {
+        return true;
+      }
+    }
+    
+    private static final class Immutable extends ParentTooYoung.Match {
+      Immutable(final Member pC, final Member pP) {
+        super(pC, pP);
+      }
+      
+      @Override
+      public boolean isMutable() {
+        return false;
+      }
+    }
+  }
+  
+  /**
+   * Generated pattern matcher API of the queries.parentTooYoung pattern,
+   * providing pattern-specific query methods.
+   * 
+   * <p>Use the pattern matcher on a given model via {@link #on(ViatraQueryEngine)},
+   * e.g. in conjunction with {@link ViatraQueryEngine#on(QueryScope)}.
+   * 
+   * <p>Matches of the pattern will be represented as {@link Match}.
+   * 
+   * <p>Original source:
+   * <code><pre>
+   * {@literal @}Constraint(message="parentTooYoung", severity="error", key={c, p})
+   * pattern parentTooYoung(c: Member, p: Member) = {
+   *    FamilyTree.members(_, c);
+   *    Member.parents(c, p);
+   *    Member.age(c, cAge);
+   *    Member.age(p, pAge);
+   *    check (pAge {@literal <}= (cAge + 12));
+   * }
+   * </pre></code>
+   * 
+   * @see Match
+   * @see ParentTooYoung
+   * 
+   */
+  public static class Matcher extends BaseMatcher<ParentTooYoung.Match> {
+    /**
+     * Initializes the pattern matcher within an existing VIATRA Query engine.
+     * If the pattern matcher is already constructed in the engine, only a light-weight reference is returned.
+     * 
+     * @param engine the existing VIATRA Query engine in which this matcher will be created.
+     * @throws ViatraQueryRuntimeException if an error occurs during pattern matcher creation
+     * 
+     */
+    public static ParentTooYoung.Matcher on(final ViatraQueryEngine engine) {
+      // check if matcher already exists
+      Matcher matcher = engine.getExistingMatcher(querySpecification());
+      if (matcher == null) {
+          matcher = (Matcher)engine.getMatcher(querySpecification());
+      }
+      return matcher;
+    }
+    
+    /**
+     * @throws ViatraQueryRuntimeException if an error occurs during pattern matcher creation
+     * @return an initialized matcher
+     * @noreference This method is for internal matcher initialization by the framework, do not call it manually.
+     * 
+     */
+    public static ParentTooYoung.Matcher create() {
+      return new Matcher();
+    }
+    
+    private static final int POSITION_C = 0;
+    
+    private static final int POSITION_P = 1;
+    
+    private static final Logger LOGGER = ViatraQueryLoggingUtil.getLogger(ParentTooYoung.Matcher.class);
+    
+    /**
+     * Initializes the pattern matcher within an existing VIATRA Query engine.
+     * If the pattern matcher is already constructed in the engine, only a light-weight reference is returned.
+     * 
+     * @param engine the existing VIATRA Query engine in which this matcher will be created.
+     * @throws ViatraQueryRuntimeException if an error occurs during pattern matcher creation
+     * 
+     */
+    private Matcher() {
+      super(querySpecification());
+    }
+    
+    /**
+     * Returns the set of all matches of the pattern that conform to the given fixed values of some parameters.
+     * @param pC the fixed value of pattern parameter c, or null if not bound.
+     * @param pP the fixed value of pattern parameter p, or null if not bound.
+     * @return matches represented as a Match object.
+     * 
+     */
+    public Collection<ParentTooYoung.Match> getAllMatches(final Member pC, final Member pP) {
+      return rawStreamAllMatches(new Object[]{pC, pP}).collect(Collectors.toSet());
+    }
+    
+    /**
+     * Returns a stream of all matches of the pattern that conform to the given fixed values of some parameters.
+     * </p>
+     * <strong>NOTE</strong>: It is important not to modify the source model while the stream is being processed.
+     * If the match set of the pattern changes during processing, the contents of the stream is <strong>undefined</strong>.
+     * In such cases, either rely on {@link #getAllMatches()} or collect the results of the stream in end-user code.
+     * @param pC the fixed value of pattern parameter c, or null if not bound.
+     * @param pP the fixed value of pattern parameter p, or null if not bound.
+     * @return a stream of matches represented as a Match object.
+     * 
+     */
+    public Stream<ParentTooYoung.Match> streamAllMatches(final Member pC, final Member pP) {
+      return rawStreamAllMatches(new Object[]{pC, pP});
+    }
+    
+    /**
+     * Returns an arbitrarily chosen match of the pattern that conforms to the given fixed values of some parameters.
+     * Neither determinism nor randomness of selection is guaranteed.
+     * @param pC the fixed value of pattern parameter c, or null if not bound.
+     * @param pP the fixed value of pattern parameter p, or null if not bound.
+     * @return a match represented as a Match object, or null if no match is found.
+     * 
+     */
+    public Optional<ParentTooYoung.Match> getOneArbitraryMatch(final Member pC, final Member pP) {
+      return rawGetOneArbitraryMatch(new Object[]{pC, pP});
+    }
+    
+    /**
+     * Indicates whether the given combination of specified pattern parameters constitute a valid pattern match,
+     * under any possible substitution of the unspecified parameters (if any).
+     * @param pC the fixed value of pattern parameter c, or null if not bound.
+     * @param pP the fixed value of pattern parameter p, or null if not bound.
+     * @return true if the input is a valid (partial) match of the pattern.
+     * 
+     */
+    public boolean hasMatch(final Member pC, final Member pP) {
+      return rawHasMatch(new Object[]{pC, pP});
+    }
+    
+    /**
+     * Returns the number of all matches of the pattern that conform to the given fixed values of some parameters.
+     * @param pC the fixed value of pattern parameter c, or null if not bound.
+     * @param pP the fixed value of pattern parameter p, or null if not bound.
+     * @return the number of pattern matches found.
+     * 
+     */
+    public int countMatches(final Member pC, final Member pP) {
+      return rawCountMatches(new Object[]{pC, pP});
+    }
+    
+    /**
+     * Executes the given processor on an arbitrarily chosen match of the pattern that conforms to the given fixed values of some parameters.
+     * Neither determinism nor randomness of selection is guaranteed.
+     * @param pC the fixed value of pattern parameter c, or null if not bound.
+     * @param pP the fixed value of pattern parameter p, or null if not bound.
+     * @param processor the action that will process the selected match.
+     * @return true if the pattern has at least one match with the given parameter values, false if the processor was not invoked
+     * 
+     */
+    public boolean forOneArbitraryMatch(final Member pC, final Member pP, final Consumer<? super ParentTooYoung.Match> processor) {
+      return rawForOneArbitraryMatch(new Object[]{pC, pP}, processor);
+    }
+    
+    /**
+     * Returns a new (partial) match.
+     * This can be used e.g. to call the matcher with a partial match.
+     * <p>The returned match will be immutable. Use {@link #newEmptyMatch()} to obtain a mutable match object.
+     * @param pC the fixed value of pattern parameter c, or null if not bound.
+     * @param pP the fixed value of pattern parameter p, or null if not bound.
+     * @return the (partial) match object.
+     * 
+     */
+    public ParentTooYoung.Match newMatch(final Member pC, final Member pP) {
+      return ParentTooYoung.Match.newMatch(pC, pP);
+    }
+    
+    /**
+     * Retrieve the set of values that occur in matches for c.
+     * @return the Set of all values or empty set if there are no matches
+     * 
+     */
+    protected Stream<Member> rawStreamAllValuesOfc(final Object[] parameters) {
+      return rawStreamAllValues(POSITION_C, parameters).map(Member.class::cast);
+    }
+    
+    /**
+     * Retrieve the set of values that occur in matches for c.
+     * @return the Set of all values or empty set if there are no matches
+     * 
+     */
+    public Set<Member> getAllValuesOfc() {
+      return rawStreamAllValuesOfc(emptyArray()).collect(Collectors.toSet());
+    }
+    
+    /**
+     * Retrieve the set of values that occur in matches for c.
+     * @return the Set of all values or empty set if there are no matches
+     * 
+     */
+    public Stream<Member> streamAllValuesOfc() {
+      return rawStreamAllValuesOfc(emptyArray());
+    }
+    
+    /**
+     * Retrieve the set of values that occur in matches for c.
+     * </p>
+     * <strong>NOTE</strong>: It is important not to modify the source model while the stream is being processed.
+     * If the match set of the pattern changes during processing, the contents of the stream is <strong>undefined</strong>.
+     * In such cases, either rely on {@link #getAllMatches()} or collect the results of the stream in end-user code.
+     *      
+     * @return the Stream of all values or empty set if there are no matches
+     * 
+     */
+    public Stream<Member> streamAllValuesOfc(final ParentTooYoung.Match partialMatch) {
+      return rawStreamAllValuesOfc(partialMatch.toArray());
+    }
+    
+    /**
+     * Retrieve the set of values that occur in matches for c.
+     * </p>
+     * <strong>NOTE</strong>: It is important not to modify the source model while the stream is being processed.
+     * If the match set of the pattern changes during processing, the contents of the stream is <strong>undefined</strong>.
+     * In such cases, either rely on {@link #getAllMatches()} or collect the results of the stream in end-user code.
+     *      
+     * @return the Stream of all values or empty set if there are no matches
+     * 
+     */
+    public Stream<Member> streamAllValuesOfc(final Member pP) {
+      return rawStreamAllValuesOfc(new Object[]{null, pP});
+    }
+    
+    /**
+     * Retrieve the set of values that occur in matches for c.
+     * @return the Set of all values or empty set if there are no matches
+     * 
+     */
+    public Set<Member> getAllValuesOfc(final ParentTooYoung.Match partialMatch) {
+      return rawStreamAllValuesOfc(partialMatch.toArray()).collect(Collectors.toSet());
+    }
+    
+    /**
+     * Retrieve the set of values that occur in matches for c.
+     * @return the Set of all values or empty set if there are no matches
+     * 
+     */
+    public Set<Member> getAllValuesOfc(final Member pP) {
+      return rawStreamAllValuesOfc(new Object[]{null, pP}).collect(Collectors.toSet());
+    }
+    
+    /**
+     * Retrieve the set of values that occur in matches for p.
+     * @return the Set of all values or empty set if there are no matches
+     * 
+     */
+    protected Stream<Member> rawStreamAllValuesOfp(final Object[] parameters) {
+      return rawStreamAllValues(POSITION_P, parameters).map(Member.class::cast);
+    }
+    
+    /**
+     * Retrieve the set of values that occur in matches for p.
+     * @return the Set of all values or empty set if there are no matches
+     * 
+     */
+    public Set<Member> getAllValuesOfp() {
+      return rawStreamAllValuesOfp(emptyArray()).collect(Collectors.toSet());
+    }
+    
+    /**
+     * Retrieve the set of values that occur in matches for p.
+     * @return the Set of all values or empty set if there are no matches
+     * 
+     */
+    public Stream<Member> streamAllValuesOfp() {
+      return rawStreamAllValuesOfp(emptyArray());
+    }
+    
+    /**
+     * Retrieve the set of values that occur in matches for p.
+     * </p>
+     * <strong>NOTE</strong>: It is important not to modify the source model while the stream is being processed.
+     * If the match set of the pattern changes during processing, the contents of the stream is <strong>undefined</strong>.
+     * In such cases, either rely on {@link #getAllMatches()} or collect the results of the stream in end-user code.
+     *      
+     * @return the Stream of all values or empty set if there are no matches
+     * 
+     */
+    public Stream<Member> streamAllValuesOfp(final ParentTooYoung.Match partialMatch) {
+      return rawStreamAllValuesOfp(partialMatch.toArray());
+    }
+    
+    /**
+     * Retrieve the set of values that occur in matches for p.
+     * </p>
+     * <strong>NOTE</strong>: It is important not to modify the source model while the stream is being processed.
+     * If the match set of the pattern changes during processing, the contents of the stream is <strong>undefined</strong>.
+     * In such cases, either rely on {@link #getAllMatches()} or collect the results of the stream in end-user code.
+     *      
+     * @return the Stream of all values or empty set if there are no matches
+     * 
+     */
+    public Stream<Member> streamAllValuesOfp(final Member pC) {
+      return rawStreamAllValuesOfp(new Object[]{pC, null});
+    }
+    
+    /**
+     * Retrieve the set of values that occur in matches for p.
+     * @return the Set of all values or empty set if there are no matches
+     * 
+     */
+    public Set<Member> getAllValuesOfp(final ParentTooYoung.Match partialMatch) {
+      return rawStreamAllValuesOfp(partialMatch.toArray()).collect(Collectors.toSet());
+    }
+    
+    /**
+     * Retrieve the set of values that occur in matches for p.
+     * @return the Set of all values or empty set if there are no matches
+     * 
+     */
+    public Set<Member> getAllValuesOfp(final Member pC) {
+      return rawStreamAllValuesOfp(new Object[]{pC, null}).collect(Collectors.toSet());
+    }
+    
+    @Override
+    protected ParentTooYoung.Match tupleToMatch(final Tuple t) {
+      try {
+          return ParentTooYoung.Match.newMatch((Member) t.get(POSITION_C), (Member) t.get(POSITION_P));
+      } catch(ClassCastException e) {
+          LOGGER.error("Element(s) in tuple not properly typed!",e);
+          return null;
+      }
+    }
+    
+    @Override
+    protected ParentTooYoung.Match arrayToMatch(final Object[] match) {
+      try {
+          return ParentTooYoung.Match.newMatch((Member) match[POSITION_C], (Member) match[POSITION_P]);
+      } catch(ClassCastException e) {
+          LOGGER.error("Element(s) in array not properly typed!",e);
+          return null;
+      }
+    }
+    
+    @Override
+    protected ParentTooYoung.Match arrayToMatchMutable(final Object[] match) {
+      try {
+          return ParentTooYoung.Match.newMutableMatch((Member) match[POSITION_C], (Member) match[POSITION_P]);
+      } catch(ClassCastException e) {
+          LOGGER.error("Element(s) in array not properly typed!",e);
+          return null;
+      }
+    }
+    
+    /**
+     * @return the singleton instance of the query specification of this pattern
+     * @throws ViatraQueryRuntimeException if the pattern definition could not be loaded
+     * 
+     */
+    public static IQuerySpecification<ParentTooYoung.Matcher> querySpecification() {
+      return ParentTooYoung.instance();
+    }
+  }
+  
+  private ParentTooYoung() {
+    super(GeneratedPQuery.INSTANCE);
+  }
+  
+  /**
+   * @return the singleton instance of the query specification
+   * @throws ViatraQueryRuntimeException if the pattern definition could not be loaded
+   * 
+   */
+  public static ParentTooYoung instance() {
+    try{
+        return LazyHolder.INSTANCE;
+    } catch (ExceptionInInitializerError err) {
+        throw processInitializerError(err);
+    }
+  }
+  
+  @Override
+  protected ParentTooYoung.Matcher instantiate(final ViatraQueryEngine engine) {
+    return ParentTooYoung.Matcher.on(engine);
+  }
+  
+  @Override
+  public ParentTooYoung.Matcher instantiate() {
+    return ParentTooYoung.Matcher.create();
+  }
+  
+  @Override
+  public ParentTooYoung.Match newEmptyMatch() {
+    return ParentTooYoung.Match.newEmptyMatch();
+  }
+  
+  @Override
+  public ParentTooYoung.Match newMatch(final Object... parameters) {
+    return ParentTooYoung.Match.newMatch((familytree.Member) parameters[0], (familytree.Member) parameters[1]);
+  }
+  
+  /**
+   * Inner class allowing the singleton instance of {@link ParentTooYoung} to be created 
+   *     <b>not</b> at the class load time of the outer class, 
+   *     but rather at the first call to {@link ParentTooYoung#instance()}.
+   * 
+   * <p> This workaround is required e.g. to support recursion.
+   * 
+   */
+  private static class LazyHolder {
+    private static final ParentTooYoung INSTANCE = new ParentTooYoung();
+    
+    /**
+     * Statically initializes the query specification <b>after</b> the field {@link #INSTANCE} is assigned.
+     * This initialization order is required to support indirect recursion.
+     * 
+     * <p> The static initializer is defined using a helper field to work around limitations of the code generator.
+     * 
+     */
+    private static final Object STATIC_INITIALIZER = ensureInitialized();
+    
+    public static Object ensureInitialized() {
+      INSTANCE.ensureInitializedInternal();
+      return null;
+    }
+  }
+  
+  private static class GeneratedPQuery extends BaseGeneratedEMFPQuery {
+    private static final ParentTooYoung.GeneratedPQuery INSTANCE = new GeneratedPQuery();
+    
+    private final PParameter parameter_c = new PParameter("c", "familytree.Member", new EClassTransitiveInstancesKey((EClass)getClassifierLiteralSafe("http://www.example.org/familytree", "Member")), PParameterDirection.INOUT);
+    
+    private final PParameter parameter_p = new PParameter("p", "familytree.Member", new EClassTransitiveInstancesKey((EClass)getClassifierLiteralSafe("http://www.example.org/familytree", "Member")), PParameterDirection.INOUT);
+    
+    private final List<PParameter> parameters = Arrays.asList(parameter_c, parameter_p);
+    
+    private GeneratedPQuery() {
+      super(PVisibility.PUBLIC);
+    }
+    
+    @Override
+    public String getFullyQualifiedName() {
+      return "queries.parentTooYoung";
+    }
+    
+    @Override
+    public List<String> getParameterNames() {
+      return Arrays.asList("c","p");
+    }
+    
+    @Override
+    public List<PParameter> getParameters() {
+      return parameters;
+    }
+    
+    @Override
+    public Set<PBody> doGetContainedBodies() {
+      setEvaluationHints(new QueryEvaluationHint(null, QueryEvaluationHint.BackendRequirement.UNSPECIFIED));
+      Set<PBody> bodies = new LinkedHashSet<>();
+      {
+          PBody body = new PBody(this);
+          PVariable var_c = body.getOrCreateVariableByName("c");
+          PVariable var_p = body.getOrCreateVariableByName("p");
+          PVariable var___0_ = body.getOrCreateVariableByName("_<0>");
+          PVariable var_cAge = body.getOrCreateVariableByName("cAge");
+          PVariable var_pAge = body.getOrCreateVariableByName("pAge");
+          new TypeConstraint(body, Tuples.flatTupleOf(var_c), new EClassTransitiveInstancesKey((EClass)getClassifierLiteral("http://www.example.org/familytree", "Member")));
+          new TypeConstraint(body, Tuples.flatTupleOf(var_p), new EClassTransitiveInstancesKey((EClass)getClassifierLiteral("http://www.example.org/familytree", "Member")));
+          body.setSymbolicParameters(Arrays.<ExportedParameter>asList(
+             new ExportedParameter(body, var_c, parameter_c),
+             new ExportedParameter(body, var_p, parameter_p)
+          ));
+          //    FamilyTree.members(_, c)
+          new TypeConstraint(body, Tuples.flatTupleOf(var___0_), new EClassTransitiveInstancesKey((EClass)getClassifierLiteral("http://www.example.org/familytree", "FamilyTree")));
+          PVariable var__virtual_0_ = body.getOrCreateVariableByName(".virtual{0}");
+          new TypeConstraint(body, Tuples.flatTupleOf(var___0_, var__virtual_0_), new EStructuralFeatureInstancesKey(getFeatureLiteral("http://www.example.org/familytree", "FamilyTree", "members")));
+          new TypeConstraint(body, Tuples.flatTupleOf(var__virtual_0_), new EClassTransitiveInstancesKey((EClass)getClassifierLiteral("http://www.example.org/familytree", "Member")));
+          new Equality(body, var__virtual_0_, var_c);
+          //    Member.parents(c, p)
+          new TypeConstraint(body, Tuples.flatTupleOf(var_c), new EClassTransitiveInstancesKey((EClass)getClassifierLiteral("http://www.example.org/familytree", "Member")));
+          PVariable var__virtual_1_ = body.getOrCreateVariableByName(".virtual{1}");
+          new TypeConstraint(body, Tuples.flatTupleOf(var_c, var__virtual_1_), new EStructuralFeatureInstancesKey(getFeatureLiteral("http://www.example.org/familytree", "Member", "parents")));
+          new TypeConstraint(body, Tuples.flatTupleOf(var__virtual_1_), new EClassTransitiveInstancesKey((EClass)getClassifierLiteral("http://www.example.org/familytree", "Member")));
+          new Equality(body, var__virtual_1_, var_p);
+          //    Member.age(c, cAge)
+          new TypeConstraint(body, Tuples.flatTupleOf(var_c), new EClassTransitiveInstancesKey((EClass)getClassifierLiteral("http://www.example.org/familytree", "Member")));
+          PVariable var__virtual_2_ = body.getOrCreateVariableByName(".virtual{2}");
+          new TypeConstraint(body, Tuples.flatTupleOf(var_c, var__virtual_2_), new EStructuralFeatureInstancesKey(getFeatureLiteral("http://www.example.org/familytree", "Member", "age")));
+          new TypeConstraint(body, Tuples.flatTupleOf(var__virtual_2_), new EDataTypeInSlotsKey((EDataType)getClassifierLiteral("http://www.eclipse.org/emf/2002/Ecore", "EInt")));
+          new Equality(body, var__virtual_2_, var_cAge);
+          //    Member.age(p, pAge)
+          new TypeConstraint(body, Tuples.flatTupleOf(var_p), new EClassTransitiveInstancesKey((EClass)getClassifierLiteral("http://www.example.org/familytree", "Member")));
+          PVariable var__virtual_3_ = body.getOrCreateVariableByName(".virtual{3}");
+          new TypeConstraint(body, Tuples.flatTupleOf(var_p, var__virtual_3_), new EStructuralFeatureInstancesKey(getFeatureLiteral("http://www.example.org/familytree", "Member", "age")));
+          new TypeConstraint(body, Tuples.flatTupleOf(var__virtual_3_), new EDataTypeInSlotsKey((EDataType)getClassifierLiteral("http://www.eclipse.org/emf/2002/Ecore", "EInt")));
+          new Equality(body, var__virtual_3_, var_pAge);
+          //    check (pAge <= (cAge + 12))
+          new ExpressionEvaluation(body, new IExpressionEvaluator() {
+          
+              @Override
+              public String getShortDescription() {
+                  return "Expression evaluation from pattern parentTooYoung";
+              }
+              
+              @Override
+              public Iterable<String> getInputParameterNames() {
+                  return Arrays.asList("cAge", "pAge");}
+          
+              @Override
+              public Object evaluateExpression(IValueProvider provider) throws Exception {
+                  Integer cAge = (Integer) provider.getValue("cAge");
+                  Integer pAge = (Integer) provider.getValue("pAge");
+                  return evaluateExpression_1_1(cAge, pAge);
+              }
+          },  null); 
+          bodies.add(body);
+      }
+      {
+          PAnnotation annotation = new PAnnotation("Constraint");
+          annotation.addAttribute("message", "parentTooYoung");
+          annotation.addAttribute("severity", "error");
+          annotation.addAttribute("key", Arrays.asList(new Object[] {
+                              new ParameterReference("c"), 
+                              new ParameterReference("p")
+                              }));
+          addAnnotation(annotation);
+      }
+      return bodies;
+    }
+  }
+  
+  private static boolean evaluateExpression_1_1(final Integer cAge, final Integer pAge) {
+    return ((pAge).intValue() <= ((cAge).intValue() + 12));
+  }
+}
diff --git a/Tests/MODELS2020-CaseStudies/case.study.familyTree.run/src-gen/queries/TwoMembersHaveNoParent.java b/Tests/MODELS2020-CaseStudies/case.study.familyTree.run/src-gen/queries/TwoMembersHaveNoParent.java
new file mode 100644
index 00000000..365939dd
--- /dev/null
+++ b/Tests/MODELS2020-CaseStudies/case.study.familyTree.run/src-gen/queries/TwoMembersHaveNoParent.java
@@ -0,0 +1,723 @@
+/**
+ * Generated from platform:/resource/case.study.familyTree.run/src/queries/familyTreeConstraints.vql
+ */
+package queries;
+
+import familytree.Member;
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.LinkedHashSet;
+import java.util.List;
+import java.util.Objects;
+import java.util.Optional;
+import java.util.Set;
+import java.util.function.Consumer;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
+import org.apache.log4j.Logger;
+import org.eclipse.emf.ecore.EClass;
+import org.eclipse.viatra.query.runtime.api.IPatternMatch;
+import org.eclipse.viatra.query.runtime.api.IQuerySpecification;
+import org.eclipse.viatra.query.runtime.api.ViatraQueryEngine;
+import org.eclipse.viatra.query.runtime.api.impl.BaseGeneratedEMFPQuery;
+import org.eclipse.viatra.query.runtime.api.impl.BaseGeneratedEMFQuerySpecification;
+import org.eclipse.viatra.query.runtime.api.impl.BaseMatcher;
+import org.eclipse.viatra.query.runtime.api.impl.BasePatternMatch;
+import org.eclipse.viatra.query.runtime.emf.types.EClassTransitiveInstancesKey;
+import org.eclipse.viatra.query.runtime.matchers.backend.QueryEvaluationHint;
+import org.eclipse.viatra.query.runtime.matchers.psystem.PBody;
+import org.eclipse.viatra.query.runtime.matchers.psystem.PVariable;
+import org.eclipse.viatra.query.runtime.matchers.psystem.annotations.PAnnotation;
+import org.eclipse.viatra.query.runtime.matchers.psystem.annotations.ParameterReference;
+import org.eclipse.viatra.query.runtime.matchers.psystem.basicdeferred.ExportedParameter;
+import org.eclipse.viatra.query.runtime.matchers.psystem.basicdeferred.Inequality;
+import org.eclipse.viatra.query.runtime.matchers.psystem.basicdeferred.NegativePatternCall;
+import org.eclipse.viatra.query.runtime.matchers.psystem.basicenumerables.TypeConstraint;
+import org.eclipse.viatra.query.runtime.matchers.psystem.queries.PParameter;
+import org.eclipse.viatra.query.runtime.matchers.psystem.queries.PParameterDirection;
+import org.eclipse.viatra.query.runtime.matchers.psystem.queries.PVisibility;
+import org.eclipse.viatra.query.runtime.matchers.tuple.Tuple;
+import org.eclipse.viatra.query.runtime.matchers.tuple.Tuples;
+import org.eclipse.viatra.query.runtime.util.ViatraQueryLoggingUtil;
+import queries.MemberHasParent;
+
+/**
+ * A pattern-specific query specification that can instantiate Matcher in a type-safe way.
+ * 
+ * <p>Original source:
+ *         <code><pre>
+ *         {@literal @}Constraint(message="twoMembersHaveNoParent", severity="error", key={m1, m2})
+ *         pattern twoMembersHaveNoParent(m1:Member, m2:Member) = {
+ *              neg find memberHasParent(m1);
+ *              neg find memberHasParent(m2);
+ *              m1 != m2;
+ *         }
+ * </pre></code>
+ * 
+ * @see Matcher
+ * @see Match
+ * 
+ */
+@SuppressWarnings("all")
+public final class TwoMembersHaveNoParent extends BaseGeneratedEMFQuerySpecification<TwoMembersHaveNoParent.Matcher> {
+  /**
+   * Pattern-specific match representation of the queries.twoMembersHaveNoParent pattern,
+   * to be used in conjunction with {@link Matcher}.
+   * 
+   * <p>Class fields correspond to parameters of the pattern. Fields with value null are considered unassigned.
+   * Each instance is a (possibly partial) substitution of pattern parameters,
+   * usable to represent a match of the pattern in the result of a query,
+   * or to specify the bound (fixed) input parameters when issuing a query.
+   * 
+   * @see Matcher
+   * 
+   */
+  public static abstract class Match extends BasePatternMatch {
+    private Member fM1;
+    
+    private Member fM2;
+    
+    private static List<String> parameterNames = makeImmutableList("m1", "m2");
+    
+    private Match(final Member pM1, final Member pM2) {
+      this.fM1 = pM1;
+      this.fM2 = pM2;
+    }
+    
+    @Override
+    public Object get(final String parameterName) {
+      switch(parameterName) {
+          case "m1": return this.fM1;
+          case "m2": return this.fM2;
+          default: return null;
+      }
+    }
+    
+    @Override
+    public Object get(final int index) {
+      switch(index) {
+          case 0: return this.fM1;
+          case 1: return this.fM2;
+          default: return null;
+      }
+    }
+    
+    public Member getM1() {
+      return this.fM1;
+    }
+    
+    public Member getM2() {
+      return this.fM2;
+    }
+    
+    @Override
+    public boolean set(final String parameterName, final Object newValue) {
+      if (!isMutable()) throw new java.lang.UnsupportedOperationException();
+      if ("m1".equals(parameterName) ) {
+          this.fM1 = (Member) newValue;
+          return true;
+      }
+      if ("m2".equals(parameterName) ) {
+          this.fM2 = (Member) newValue;
+          return true;
+      }
+      return false;
+    }
+    
+    public void setM1(final Member pM1) {
+      if (!isMutable()) throw new java.lang.UnsupportedOperationException();
+      this.fM1 = pM1;
+    }
+    
+    public void setM2(final Member pM2) {
+      if (!isMutable()) throw new java.lang.UnsupportedOperationException();
+      this.fM2 = pM2;
+    }
+    
+    @Override
+    public String patternName() {
+      return "queries.twoMembersHaveNoParent";
+    }
+    
+    @Override
+    public List<String> parameterNames() {
+      return TwoMembersHaveNoParent.Match.parameterNames;
+    }
+    
+    @Override
+    public Object[] toArray() {
+      return new Object[]{fM1, fM2};
+    }
+    
+    @Override
+    public TwoMembersHaveNoParent.Match toImmutable() {
+      return isMutable() ? newMatch(fM1, fM2) : this;
+    }
+    
+    @Override
+    public String prettyPrint() {
+      StringBuilder result = new StringBuilder();
+      result.append("\"m1\"=" + prettyPrintValue(fM1) + ", ");
+      result.append("\"m2\"=" + prettyPrintValue(fM2));
+      return result.toString();
+    }
+    
+    @Override
+    public int hashCode() {
+      return Objects.hash(fM1, fM2);
+    }
+    
+    @Override
+    public boolean equals(final Object obj) {
+      if (this == obj)
+          return true;
+      if (obj == null) {
+          return false;
+      }
+      if ((obj instanceof TwoMembersHaveNoParent.Match)) {
+          TwoMembersHaveNoParent.Match other = (TwoMembersHaveNoParent.Match) obj;
+          return Objects.equals(fM1, other.fM1) && Objects.equals(fM2, other.fM2);
+      } else {
+          // this should be infrequent
+          if (!(obj instanceof IPatternMatch)) {
+              return false;
+          }
+          IPatternMatch otherSig  = (IPatternMatch) obj;
+          return Objects.equals(specification(), otherSig.specification()) && Arrays.deepEquals(toArray(), otherSig.toArray());
+      }
+    }
+    
+    @Override
+    public TwoMembersHaveNoParent specification() {
+      return TwoMembersHaveNoParent.instance();
+    }
+    
+    /**
+     * Returns an empty, mutable match.
+     * Fields of the mutable match can be filled to create a partial match, usable as matcher input.
+     * 
+     * @return the empty match.
+     * 
+     */
+    public static TwoMembersHaveNoParent.Match newEmptyMatch() {
+      return new Mutable(null, null);
+    }
+    
+    /**
+     * Returns a mutable (partial) match.
+     * Fields of the mutable match can be filled to create a partial match, usable as matcher input.
+     * 
+     * @param pM1 the fixed value of pattern parameter m1, or null if not bound.
+     * @param pM2 the fixed value of pattern parameter m2, or null if not bound.
+     * @return the new, mutable (partial) match object.
+     * 
+     */
+    public static TwoMembersHaveNoParent.Match newMutableMatch(final Member pM1, final Member pM2) {
+      return new Mutable(pM1, pM2);
+    }
+    
+    /**
+     * Returns a new (partial) match.
+     * This can be used e.g. to call the matcher with a partial match.
+     * <p>The returned match will be immutable. Use {@link #newEmptyMatch()} to obtain a mutable match object.
+     * @param pM1 the fixed value of pattern parameter m1, or null if not bound.
+     * @param pM2 the fixed value of pattern parameter m2, or null if not bound.
+     * @return the (partial) match object.
+     * 
+     */
+    public static TwoMembersHaveNoParent.Match newMatch(final Member pM1, final Member pM2) {
+      return new Immutable(pM1, pM2);
+    }
+    
+    private static final class Mutable extends TwoMembersHaveNoParent.Match {
+      Mutable(final Member pM1, final Member pM2) {
+        super(pM1, pM2);
+      }
+      
+      @Override
+      public boolean isMutable() {
+        return true;
+      }
+    }
+    
+    private static final class Immutable extends TwoMembersHaveNoParent.Match {
+      Immutable(final Member pM1, final Member pM2) {
+        super(pM1, pM2);
+      }
+      
+      @Override
+      public boolean isMutable() {
+        return false;
+      }
+    }
+  }
+  
+  /**
+   * Generated pattern matcher API of the queries.twoMembersHaveNoParent pattern,
+   * providing pattern-specific query methods.
+   * 
+   * <p>Use the pattern matcher on a given model via {@link #on(ViatraQueryEngine)},
+   * e.g. in conjunction with {@link ViatraQueryEngine#on(QueryScope)}.
+   * 
+   * <p>Matches of the pattern will be represented as {@link Match}.
+   * 
+   * <p>Original source:
+   * <code><pre>
+   * {@literal @}Constraint(message="twoMembersHaveNoParent", severity="error", key={m1, m2})
+   * pattern twoMembersHaveNoParent(m1:Member, m2:Member) = {
+   *    neg find memberHasParent(m1);
+   *    neg find memberHasParent(m2);
+   *    m1 != m2;
+   * }
+   * </pre></code>
+   * 
+   * @see Match
+   * @see TwoMembersHaveNoParent
+   * 
+   */
+  public static class Matcher extends BaseMatcher<TwoMembersHaveNoParent.Match> {
+    /**
+     * Initializes the pattern matcher within an existing VIATRA Query engine.
+     * If the pattern matcher is already constructed in the engine, only a light-weight reference is returned.
+     * 
+     * @param engine the existing VIATRA Query engine in which this matcher will be created.
+     * @throws ViatraQueryRuntimeException if an error occurs during pattern matcher creation
+     * 
+     */
+    public static TwoMembersHaveNoParent.Matcher on(final ViatraQueryEngine engine) {
+      // check if matcher already exists
+      Matcher matcher = engine.getExistingMatcher(querySpecification());
+      if (matcher == null) {
+          matcher = (Matcher)engine.getMatcher(querySpecification());
+      }
+      return matcher;
+    }
+    
+    /**
+     * @throws ViatraQueryRuntimeException if an error occurs during pattern matcher creation
+     * @return an initialized matcher
+     * @noreference This method is for internal matcher initialization by the framework, do not call it manually.
+     * 
+     */
+    public static TwoMembersHaveNoParent.Matcher create() {
+      return new Matcher();
+    }
+    
+    private static final int POSITION_M1 = 0;
+    
+    private static final int POSITION_M2 = 1;
+    
+    private static final Logger LOGGER = ViatraQueryLoggingUtil.getLogger(TwoMembersHaveNoParent.Matcher.class);
+    
+    /**
+     * Initializes the pattern matcher within an existing VIATRA Query engine.
+     * If the pattern matcher is already constructed in the engine, only a light-weight reference is returned.
+     * 
+     * @param engine the existing VIATRA Query engine in which this matcher will be created.
+     * @throws ViatraQueryRuntimeException if an error occurs during pattern matcher creation
+     * 
+     */
+    private Matcher() {
+      super(querySpecification());
+    }
+    
+    /**
+     * Returns the set of all matches of the pattern that conform to the given fixed values of some parameters.
+     * @param pM1 the fixed value of pattern parameter m1, or null if not bound.
+     * @param pM2 the fixed value of pattern parameter m2, or null if not bound.
+     * @return matches represented as a Match object.
+     * 
+     */
+    public Collection<TwoMembersHaveNoParent.Match> getAllMatches(final Member pM1, final Member pM2) {
+      return rawStreamAllMatches(new Object[]{pM1, pM2}).collect(Collectors.toSet());
+    }
+    
+    /**
+     * Returns a stream of all matches of the pattern that conform to the given fixed values of some parameters.
+     * </p>
+     * <strong>NOTE</strong>: It is important not to modify the source model while the stream is being processed.
+     * If the match set of the pattern changes during processing, the contents of the stream is <strong>undefined</strong>.
+     * In such cases, either rely on {@link #getAllMatches()} or collect the results of the stream in end-user code.
+     * @param pM1 the fixed value of pattern parameter m1, or null if not bound.
+     * @param pM2 the fixed value of pattern parameter m2, or null if not bound.
+     * @return a stream of matches represented as a Match object.
+     * 
+     */
+    public Stream<TwoMembersHaveNoParent.Match> streamAllMatches(final Member pM1, final Member pM2) {
+      return rawStreamAllMatches(new Object[]{pM1, pM2});
+    }
+    
+    /**
+     * Returns an arbitrarily chosen match of the pattern that conforms to the given fixed values of some parameters.
+     * Neither determinism nor randomness of selection is guaranteed.
+     * @param pM1 the fixed value of pattern parameter m1, or null if not bound.
+     * @param pM2 the fixed value of pattern parameter m2, or null if not bound.
+     * @return a match represented as a Match object, or null if no match is found.
+     * 
+     */
+    public Optional<TwoMembersHaveNoParent.Match> getOneArbitraryMatch(final Member pM1, final Member pM2) {
+      return rawGetOneArbitraryMatch(new Object[]{pM1, pM2});
+    }
+    
+    /**
+     * Indicates whether the given combination of specified pattern parameters constitute a valid pattern match,
+     * under any possible substitution of the unspecified parameters (if any).
+     * @param pM1 the fixed value of pattern parameter m1, or null if not bound.
+     * @param pM2 the fixed value of pattern parameter m2, or null if not bound.
+     * @return true if the input is a valid (partial) match of the pattern.
+     * 
+     */
+    public boolean hasMatch(final Member pM1, final Member pM2) {
+      return rawHasMatch(new Object[]{pM1, pM2});
+    }
+    
+    /**
+     * Returns the number of all matches of the pattern that conform to the given fixed values of some parameters.
+     * @param pM1 the fixed value of pattern parameter m1, or null if not bound.
+     * @param pM2 the fixed value of pattern parameter m2, or null if not bound.
+     * @return the number of pattern matches found.
+     * 
+     */
+    public int countMatches(final Member pM1, final Member pM2) {
+      return rawCountMatches(new Object[]{pM1, pM2});
+    }
+    
+    /**
+     * Executes the given processor on an arbitrarily chosen match of the pattern that conforms to the given fixed values of some parameters.
+     * Neither determinism nor randomness of selection is guaranteed.
+     * @param pM1 the fixed value of pattern parameter m1, or null if not bound.
+     * @param pM2 the fixed value of pattern parameter m2, or null if not bound.
+     * @param processor the action that will process the selected match.
+     * @return true if the pattern has at least one match with the given parameter values, false if the processor was not invoked
+     * 
+     */
+    public boolean forOneArbitraryMatch(final Member pM1, final Member pM2, final Consumer<? super TwoMembersHaveNoParent.Match> processor) {
+      return rawForOneArbitraryMatch(new Object[]{pM1, pM2}, processor);
+    }
+    
+    /**
+     * Returns a new (partial) match.
+     * This can be used e.g. to call the matcher with a partial match.
+     * <p>The returned match will be immutable. Use {@link #newEmptyMatch()} to obtain a mutable match object.
+     * @param pM1 the fixed value of pattern parameter m1, or null if not bound.
+     * @param pM2 the fixed value of pattern parameter m2, or null if not bound.
+     * @return the (partial) match object.
+     * 
+     */
+    public TwoMembersHaveNoParent.Match newMatch(final Member pM1, final Member pM2) {
+      return TwoMembersHaveNoParent.Match.newMatch(pM1, pM2);
+    }
+    
+    /**
+     * Retrieve the set of values that occur in matches for m1.
+     * @return the Set of all values or empty set if there are no matches
+     * 
+     */
+    protected Stream<Member> rawStreamAllValuesOfm1(final Object[] parameters) {
+      return rawStreamAllValues(POSITION_M1, parameters).map(Member.class::cast);
+    }
+    
+    /**
+     * Retrieve the set of values that occur in matches for m1.
+     * @return the Set of all values or empty set if there are no matches
+     * 
+     */
+    public Set<Member> getAllValuesOfm1() {
+      return rawStreamAllValuesOfm1(emptyArray()).collect(Collectors.toSet());
+    }
+    
+    /**
+     * Retrieve the set of values that occur in matches for m1.
+     * @return the Set of all values or empty set if there are no matches
+     * 
+     */
+    public Stream<Member> streamAllValuesOfm1() {
+      return rawStreamAllValuesOfm1(emptyArray());
+    }
+    
+    /**
+     * Retrieve the set of values that occur in matches for m1.
+     * </p>
+     * <strong>NOTE</strong>: It is important not to modify the source model while the stream is being processed.
+     * If the match set of the pattern changes during processing, the contents of the stream is <strong>undefined</strong>.
+     * In such cases, either rely on {@link #getAllMatches()} or collect the results of the stream in end-user code.
+     *      
+     * @return the Stream of all values or empty set if there are no matches
+     * 
+     */
+    public Stream<Member> streamAllValuesOfm1(final TwoMembersHaveNoParent.Match partialMatch) {
+      return rawStreamAllValuesOfm1(partialMatch.toArray());
+    }
+    
+    /**
+     * Retrieve the set of values that occur in matches for m1.
+     * </p>
+     * <strong>NOTE</strong>: It is important not to modify the source model while the stream is being processed.
+     * If the match set of the pattern changes during processing, the contents of the stream is <strong>undefined</strong>.
+     * In such cases, either rely on {@link #getAllMatches()} or collect the results of the stream in end-user code.
+     *      
+     * @return the Stream of all values or empty set if there are no matches
+     * 
+     */
+    public Stream<Member> streamAllValuesOfm1(final Member pM2) {
+      return rawStreamAllValuesOfm1(new Object[]{null, pM2});
+    }
+    
+    /**
+     * Retrieve the set of values that occur in matches for m1.
+     * @return the Set of all values or empty set if there are no matches
+     * 
+     */
+    public Set<Member> getAllValuesOfm1(final TwoMembersHaveNoParent.Match partialMatch) {
+      return rawStreamAllValuesOfm1(partialMatch.toArray()).collect(Collectors.toSet());
+    }
+    
+    /**
+     * Retrieve the set of values that occur in matches for m1.
+     * @return the Set of all values or empty set if there are no matches
+     * 
+     */
+    public Set<Member> getAllValuesOfm1(final Member pM2) {
+      return rawStreamAllValuesOfm1(new Object[]{null, pM2}).collect(Collectors.toSet());
+    }
+    
+    /**
+     * Retrieve the set of values that occur in matches for m2.
+     * @return the Set of all values or empty set if there are no matches
+     * 
+     */
+    protected Stream<Member> rawStreamAllValuesOfm2(final Object[] parameters) {
+      return rawStreamAllValues(POSITION_M2, parameters).map(Member.class::cast);
+    }
+    
+    /**
+     * Retrieve the set of values that occur in matches for m2.
+     * @return the Set of all values or empty set if there are no matches
+     * 
+     */
+    public Set<Member> getAllValuesOfm2() {
+      return rawStreamAllValuesOfm2(emptyArray()).collect(Collectors.toSet());
+    }
+    
+    /**
+     * Retrieve the set of values that occur in matches for m2.
+     * @return the Set of all values or empty set if there are no matches
+     * 
+     */
+    public Stream<Member> streamAllValuesOfm2() {
+      return rawStreamAllValuesOfm2(emptyArray());
+    }
+    
+    /**
+     * Retrieve the set of values that occur in matches for m2.
+     * </p>
+     * <strong>NOTE</strong>: It is important not to modify the source model while the stream is being processed.
+     * If the match set of the pattern changes during processing, the contents of the stream is <strong>undefined</strong>.
+     * In such cases, either rely on {@link #getAllMatches()} or collect the results of the stream in end-user code.
+     *      
+     * @return the Stream of all values or empty set if there are no matches
+     * 
+     */
+    public Stream<Member> streamAllValuesOfm2(final TwoMembersHaveNoParent.Match partialMatch) {
+      return rawStreamAllValuesOfm2(partialMatch.toArray());
+    }
+    
+    /**
+     * Retrieve the set of values that occur in matches for m2.
+     * </p>
+     * <strong>NOTE</strong>: It is important not to modify the source model while the stream is being processed.
+     * If the match set of the pattern changes during processing, the contents of the stream is <strong>undefined</strong>.
+     * In such cases, either rely on {@link #getAllMatches()} or collect the results of the stream in end-user code.
+     *      
+     * @return the Stream of all values or empty set if there are no matches
+     * 
+     */
+    public Stream<Member> streamAllValuesOfm2(final Member pM1) {
+      return rawStreamAllValuesOfm2(new Object[]{pM1, null});
+    }
+    
+    /**
+     * Retrieve the set of values that occur in matches for m2.
+     * @return the Set of all values or empty set if there are no matches
+     * 
+     */
+    public Set<Member> getAllValuesOfm2(final TwoMembersHaveNoParent.Match partialMatch) {
+      return rawStreamAllValuesOfm2(partialMatch.toArray()).collect(Collectors.toSet());
+    }
+    
+    /**
+     * Retrieve the set of values that occur in matches for m2.
+     * @return the Set of all values or empty set if there are no matches
+     * 
+     */
+    public Set<Member> getAllValuesOfm2(final Member pM1) {
+      return rawStreamAllValuesOfm2(new Object[]{pM1, null}).collect(Collectors.toSet());
+    }
+    
+    @Override
+    protected TwoMembersHaveNoParent.Match tupleToMatch(final Tuple t) {
+      try {
+          return TwoMembersHaveNoParent.Match.newMatch((Member) t.get(POSITION_M1), (Member) t.get(POSITION_M2));
+      } catch(ClassCastException e) {
+          LOGGER.error("Element(s) in tuple not properly typed!",e);
+          return null;
+      }
+    }
+    
+    @Override
+    protected TwoMembersHaveNoParent.Match arrayToMatch(final Object[] match) {
+      try {
+          return TwoMembersHaveNoParent.Match.newMatch((Member) match[POSITION_M1], (Member) match[POSITION_M2]);
+      } catch(ClassCastException e) {
+          LOGGER.error("Element(s) in array not properly typed!",e);
+          return null;
+      }
+    }
+    
+    @Override
+    protected TwoMembersHaveNoParent.Match arrayToMatchMutable(final Object[] match) {
+      try {
+          return TwoMembersHaveNoParent.Match.newMutableMatch((Member) match[POSITION_M1], (Member) match[POSITION_M2]);
+      } catch(ClassCastException e) {
+          LOGGER.error("Element(s) in array not properly typed!",e);
+          return null;
+      }
+    }
+    
+    /**
+     * @return the singleton instance of the query specification of this pattern
+     * @throws ViatraQueryRuntimeException if the pattern definition could not be loaded
+     * 
+     */
+    public static IQuerySpecification<TwoMembersHaveNoParent.Matcher> querySpecification() {
+      return TwoMembersHaveNoParent.instance();
+    }
+  }
+  
+  private TwoMembersHaveNoParent() {
+    super(GeneratedPQuery.INSTANCE);
+  }
+  
+  /**
+   * @return the singleton instance of the query specification
+   * @throws ViatraQueryRuntimeException if the pattern definition could not be loaded
+   * 
+   */
+  public static TwoMembersHaveNoParent instance() {
+    try{
+        return LazyHolder.INSTANCE;
+    } catch (ExceptionInInitializerError err) {
+        throw processInitializerError(err);
+    }
+  }
+  
+  @Override
+  protected TwoMembersHaveNoParent.Matcher instantiate(final ViatraQueryEngine engine) {
+    return TwoMembersHaveNoParent.Matcher.on(engine);
+  }
+  
+  @Override
+  public TwoMembersHaveNoParent.Matcher instantiate() {
+    return TwoMembersHaveNoParent.Matcher.create();
+  }
+  
+  @Override
+  public TwoMembersHaveNoParent.Match newEmptyMatch() {
+    return TwoMembersHaveNoParent.Match.newEmptyMatch();
+  }
+  
+  @Override
+  public TwoMembersHaveNoParent.Match newMatch(final Object... parameters) {
+    return TwoMembersHaveNoParent.Match.newMatch((familytree.Member) parameters[0], (familytree.Member) parameters[1]);
+  }
+  
+  /**
+   * Inner class allowing the singleton instance of {@link TwoMembersHaveNoParent} to be created 
+   *     <b>not</b> at the class load time of the outer class, 
+   *     but rather at the first call to {@link TwoMembersHaveNoParent#instance()}.
+   * 
+   * <p> This workaround is required e.g. to support recursion.
+   * 
+   */
+  private static class LazyHolder {
+    private static final TwoMembersHaveNoParent INSTANCE = new TwoMembersHaveNoParent();
+    
+    /**
+     * Statically initializes the query specification <b>after</b> the field {@link #INSTANCE} is assigned.
+     * This initialization order is required to support indirect recursion.
+     * 
+     * <p> The static initializer is defined using a helper field to work around limitations of the code generator.
+     * 
+     */
+    private static final Object STATIC_INITIALIZER = ensureInitialized();
+    
+    public static Object ensureInitialized() {
+      INSTANCE.ensureInitializedInternal();
+      return null;
+    }
+  }
+  
+  private static class GeneratedPQuery extends BaseGeneratedEMFPQuery {
+    private static final TwoMembersHaveNoParent.GeneratedPQuery INSTANCE = new GeneratedPQuery();
+    
+    private final PParameter parameter_m1 = new PParameter("m1", "familytree.Member", new EClassTransitiveInstancesKey((EClass)getClassifierLiteralSafe("http://www.example.org/familytree", "Member")), PParameterDirection.INOUT);
+    
+    private final PParameter parameter_m2 = new PParameter("m2", "familytree.Member", new EClassTransitiveInstancesKey((EClass)getClassifierLiteralSafe("http://www.example.org/familytree", "Member")), PParameterDirection.INOUT);
+    
+    private final List<PParameter> parameters = Arrays.asList(parameter_m1, parameter_m2);
+    
+    private GeneratedPQuery() {
+      super(PVisibility.PUBLIC);
+    }
+    
+    @Override
+    public String getFullyQualifiedName() {
+      return "queries.twoMembersHaveNoParent";
+    }
+    
+    @Override
+    public List<String> getParameterNames() {
+      return Arrays.asList("m1","m2");
+    }
+    
+    @Override
+    public List<PParameter> getParameters() {
+      return parameters;
+    }
+    
+    @Override
+    public Set<PBody> doGetContainedBodies() {
+      setEvaluationHints(new QueryEvaluationHint(null, QueryEvaluationHint.BackendRequirement.UNSPECIFIED));
+      Set<PBody> bodies = new LinkedHashSet<>();
+      {
+          PBody body = new PBody(this);
+          PVariable var_m1 = body.getOrCreateVariableByName("m1");
+          PVariable var_m2 = body.getOrCreateVariableByName("m2");
+          new TypeConstraint(body, Tuples.flatTupleOf(var_m1), new EClassTransitiveInstancesKey((EClass)getClassifierLiteral("http://www.example.org/familytree", "Member")));
+          new TypeConstraint(body, Tuples.flatTupleOf(var_m2), new EClassTransitiveInstancesKey((EClass)getClassifierLiteral("http://www.example.org/familytree", "Member")));
+          body.setSymbolicParameters(Arrays.<ExportedParameter>asList(
+             new ExportedParameter(body, var_m1, parameter_m1),
+             new ExportedParameter(body, var_m2, parameter_m2)
+          ));
+          //    neg find memberHasParent(m1)
+          new NegativePatternCall(body, Tuples.flatTupleOf(var_m1), MemberHasParent.instance().getInternalQueryRepresentation());
+          //    neg find memberHasParent(m2)
+          new NegativePatternCall(body, Tuples.flatTupleOf(var_m2), MemberHasParent.instance().getInternalQueryRepresentation());
+          //    m1 != m2
+          new Inequality(body, var_m1, var_m2);
+          bodies.add(body);
+      }
+      {
+          PAnnotation annotation = new PAnnotation("Constraint");
+          annotation.addAttribute("message", "twoMembersHaveNoParent");
+          annotation.addAttribute("severity", "error");
+          annotation.addAttribute("key", Arrays.asList(new Object[] {
+                              new ParameterReference("m1"), 
+                              new ParameterReference("m2")
+                              }));
+          addAnnotation(annotation);
+      }
+      return bodies;
+    }
+  }
+}
diff --git a/Tests/MODELS2020-CaseStudies/case.study.pledge.originalFiles/xtend-gen/converter/.UML2TGF.xtendbin b/Tests/MODELS2020-CaseStudies/case.study.pledge.originalFiles/xtend-gen/converter/.UML2TGF.xtendbin
index 2890feb7..d5f0c05c 100644
--- a/Tests/MODELS2020-CaseStudies/case.study.pledge.originalFiles/xtend-gen/converter/.UML2TGF.xtendbin
+++ b/Tests/MODELS2020-CaseStudies/case.study.pledge.originalFiles/xtend-gen/converter/.UML2TGF.xtendbin
diff --git a/Tests/MODELS2020-CaseStudies/case.study.pledge.originalFiles/xtend-gen/converter/.gitignore b/Tests/MODELS2020-CaseStudies/case.study.pledge.originalFiles/xtend-gen/converter/.gitignore
index 2df5d1c0..7a39cb70 100644
--- a/Tests/MODELS2020-CaseStudies/case.study.pledge.originalFiles/xtend-gen/converter/.gitignore
+++ b/Tests/MODELS2020-CaseStudies/case.study.pledge.originalFiles/xtend-gen/converter/.gitignore
@@ -1 +1,3 @@
 /.UML2TGF.java._trace
+/.UML2TGF.xtendbin
+/UML2TGF.java
diff --git a/Tests/MODELS2020-CaseStudies/case.study.pledge.run/bin/.gitignore b/Tests/MODELS2020-CaseStudies/case.study.pledge.run/bin/.gitignore
index 07e30191..e8806810 100644
--- a/Tests/MODELS2020-CaseStudies/case.study.pledge.run/bin/.gitignore
+++ b/Tests/MODELS2020-CaseStudies/case.study.pledge.run/bin/.gitignore
@@ -1 +1,2 @@
 /run/
+/queries/
diff --git a/Tests/MODELS2020-CaseStudies/case.study.pledge.run/plugin.xml b/Tests/MODELS2020-CaseStudies/case.study.pledge.run/plugin.xml
index 63aa0b02..8b036ff2 100644
--- a/Tests/MODELS2020-CaseStudies/case.study.pledge.run/plugin.xml
+++ b/Tests/MODELS2020-CaseStudies/case.study.pledge.run/plugin.xml
@@ -1,42 +1,42 @@
-<?xml version="1.0" encoding="UTF-8"?><plugin>

-  <extension id="queries.Case_study_A" point="org.eclipse.viatra.query.runtime.queryspecification">

-    <group group="org.eclipse.viatra.query.runtime.extensibility.SingletonExtensionFactory:queries.Case_study_A" id="queries.Case_study_A">

-      <query-specification fqn="queries.inv03"/>

-      <query-specification fqn="queries.x_inv03_eligAll"/>

-      <query-specification fqn="queries.x_inv03_hasAll"/>

-      <query-specification fqn="queries.inv05"/>

-      <query-specification fqn="queries.x_inv05_inRange"/>

-      <query-specification fqn="queries.inv06"/>

-      <query-specification fqn="queries.inv07"/>

-      <query-specification fqn="queries.inv08"/>

-      <query-specification fqn="queries.x_inv08_notEI"/>

-      <query-specification fqn="queries.x_inv08_noType"/>

-      <query-specification fqn="queries.x_inv08_inRange"/>

-      <query-specification fqn="queries.inv10"/>

-      <query-specification fqn="queries.inv11"/>

-      <query-specification fqn="queries.x_inv11_incOver100"/>

-      <query-specification fqn="queries.x_inv11_incNotOver100"/>

-      <query-specification fqn="queries.inv12"/>

-      <query-specification fqn="queries.x_inv12_notNonRes"/>

-      <query-specification fqn="queries.x_inv12_notZZ"/>

-      <query-specification fqn="queries.inv13"/>

-      <query-specification fqn="queries.x_inv13"/>

-      <query-specification fqn="queries.inv15"/>

-      <query-specification fqn="queries.x_inv15"/>

-      <query-specification fqn="queries.inv17"/>

-      <query-specification fqn="queries.inv20"/>

-      <query-specification fqn="queries.inv33"/>

-      <query-specification fqn="queries.inv34"/>

-      <query-specification fqn="queries.inv35"/>

-      <query-specification fqn="queries.inv47"/>

-      <query-specification fqn="queries.x_inv47"/>

-      <query-specification fqn="queries.inv48"/>

-      <query-specification fqn="queries.x_inv48_notDis"/>

-      <query-specification fqn="queries.x_inv48_Dis"/>

-      <query-specification fqn="queries.x_inv48_3"/>

-      <query-specification fqn="queries.inv49"/>

-      <query-specification fqn="queries.x_inv49_1"/>

-      <query-specification fqn="queries.x_inv49_2"/>

-    </group>

-  </extension>

-</plugin>

+<?xml version="1.0" encoding="UTF-8"?><plugin>
+  <extension id="queries.Case_study_A" point="org.eclipse.viatra.query.runtime.queryspecification">
+    <group group="org.eclipse.viatra.query.runtime.extensibility.SingletonExtensionFactory:queries.Case_study_A" id="queries.Case_study_A">
+      <query-specification fqn="queries.inv03"/>
+      <query-specification fqn="queries.x_inv03_eligAll"/>
+      <query-specification fqn="queries.x_inv03_hasAll"/>
+      <query-specification fqn="queries.inv05"/>
+      <query-specification fqn="queries.x_inv05_inRange"/>
+      <query-specification fqn="queries.inv06"/>
+      <query-specification fqn="queries.inv07"/>
+      <query-specification fqn="queries.inv08"/>
+      <query-specification fqn="queries.x_inv08_notEI"/>
+      <query-specification fqn="queries.x_inv08_noType"/>
+      <query-specification fqn="queries.x_inv08_inRange"/>
+      <query-specification fqn="queries.inv10"/>
+      <query-specification fqn="queries.inv11"/>
+      <query-specification fqn="queries.x_inv11_incOver100"/>
+      <query-specification fqn="queries.x_inv11_incNotOver100"/>
+      <query-specification fqn="queries.inv12"/>
+      <query-specification fqn="queries.x_inv12_notNonRes"/>
+      <query-specification fqn="queries.x_inv12_notZZ"/>
+      <query-specification fqn="queries.inv13"/>
+      <query-specification fqn="queries.x_inv13"/>
+      <query-specification fqn="queries.inv15"/>
+      <query-specification fqn="queries.x_inv15"/>
+      <query-specification fqn="queries.inv17"/>
+      <query-specification fqn="queries.inv20"/>
+      <query-specification fqn="queries.inv33"/>
+      <query-specification fqn="queries.inv34"/>
+      <query-specification fqn="queries.inv35"/>
+      <query-specification fqn="queries.inv47"/>
+      <query-specification fqn="queries.x_inv47"/>
+      <query-specification fqn="queries.inv48"/>
+      <query-specification fqn="queries.x_inv48_notDis"/>
+      <query-specification fqn="queries.x_inv48_Dis"/>
+      <query-specification fqn="queries.x_inv48_3"/>
+      <query-specification fqn="queries.inv49"/>
+      <query-specification fqn="queries.x_inv49_1"/>
+      <query-specification fqn="queries.x_inv49_2"/>
+    </group>
+  </extension>
+</plugin>
diff --git a/Tests/MODELS2020-CaseStudies/case.study.pledge.run/xtend-gen/run/.GeneratePledgeModels.xtendbin b/Tests/MODELS2020-CaseStudies/case.study.pledge.run/xtend-gen/run/.GeneratePledgeModels.xtendbin
index c5572067..0b00309c 100644
--- a/Tests/MODELS2020-CaseStudies/case.study.pledge.run/xtend-gen/run/.GeneratePledgeModels.xtendbin
+++ b/Tests/MODELS2020-CaseStudies/case.study.pledge.run/xtend-gen/run/.GeneratePledgeModels.xtendbin