5 files changed, 1132 insertions, 36 deletions

diff --git a/Domains/hu.bme.mit.inf.dslreasoner.domains.alloyexamples/src-gen/hu/bme/mit/inf/dslreasoner/domains/alloyexamples/.gitignore b/Domains/hu.bme.mit.inf.dslreasoner.domains.alloyexamples/src-gen/hu/bme/mit/inf/dslreasoner/domains/alloyexamples/.gitignore
index 1e7d444f..fa9b1325 100644
--- a/Domains/hu.bme.mit.inf.dslreasoner.domains.alloyexamples/src-gen/hu/bme/mit/inf/dslreasoner/domains/alloyexamples/.gitignore
+++ b/Domains/hu.bme.mit.inf.dslreasoner.domains.alloyexamples/src-gen/hu/bme/mit/inf/dslreasoner/domains/alloyexamples/.gitignore
@@ -50,3 +50,5 @@
 /Opposite.java
 /OppositeDifferentClass.java
 /PatternContent.java
+/.Dir.java._trace
+/.RootIsNotDir.java._trace
diff --git a/Domains/hu.bme.mit.inf.dslreasoner.domains.alloyexamples/src-gen/hu/bme/mit/inf/dslreasoner/domains/alloyexamples/Dir.java b/Domains/hu.bme.mit.inf.dslreasoner.domains.alloyexamples/src-gen/hu/bme/mit/inf/dslreasoner/domains/alloyexamples/Dir.java
new file mode 100644
index 00000000..ad04c098
--- /dev/null
+++ b/Domains/hu.bme.mit.inf.dslreasoner.domains.alloyexamples/src-gen/hu/bme/mit/inf/dslreasoner/domains/alloyexamples/Dir.java
@@ -0,0 +1,533 @@
+/**
+ * Generated from platform:/resource/hu.bme.mit.inf.dslreasoner.domains.alloyexamples/patterns/hu/bme/mit/inf/dslreasoner/domains/alloyexamples/FileSystem.vql
+ */
+package hu.bme.mit.inf.dslreasoner.domains.alloyexamples;
+
+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.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 dir(d: Dir) {
+ *              Dir(d);
+ *         }
+ * </pre></code>
+ * 
+ * @see Matcher
+ * @see Match
+ * 
+ */
+@SuppressWarnings("all")
+public final class Dir extends BaseGeneratedEMFQuerySpecification<Dir.Matcher> {
+  /**
+   * Pattern-specific match representation of the hu.bme.mit.inf.dslreasoner.domains.alloyexamples.dir 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 hu.bme.mit.inf.dslreasoner.domains.alloyexamples.Filesystem.Dir fD;
+    
+    private static List<String> parameterNames = makeImmutableList("d");
+    
+    private Match(final hu.bme.mit.inf.dslreasoner.domains.alloyexamples.Filesystem.Dir pD) {
+      this.fD = pD;
+    }
+    
+    @Override
+    public Object get(final String parameterName) {
+      if ("d".equals(parameterName)) return this.fD;
+      return null;
+    }
+    
+    public hu.bme.mit.inf.dslreasoner.domains.alloyexamples.Filesystem.Dir getD() {
+      return this.fD;
+    }
+    
+    @Override
+    public boolean set(final String parameterName, final Object newValue) {
+      if (!isMutable()) throw new java.lang.UnsupportedOperationException();
+      if ("d".equals(parameterName) ) {
+          this.fD = (hu.bme.mit.inf.dslreasoner.domains.alloyexamples.Filesystem.Dir) newValue;
+          return true;
+      }
+      return false;
+    }
+    
+    public void setD(final hu.bme.mit.inf.dslreasoner.domains.alloyexamples.Filesystem.Dir pD) {
+      if (!isMutable()) throw new java.lang.UnsupportedOperationException();
+      this.fD = pD;
+    }
+    
+    @Override
+    public String patternName() {
+      return "hu.bme.mit.inf.dslreasoner.domains.alloyexamples.dir";
+    }
+    
+    @Override
+    public List<String> parameterNames() {
+      return Dir.Match.parameterNames;
+    }
+    
+    @Override
+    public Object[] toArray() {
+      return new Object[]{fD};
+    }
+    
+    @Override
+    public Dir.Match toImmutable() {
+      return isMutable() ? newMatch(fD) : this;
+    }
+    
+    @Override
+    public String prettyPrint() {
+      StringBuilder result = new StringBuilder();
+      result.append("\"d\"=" + prettyPrintValue(fD));
+      return result.toString();
+    }
+    
+    @Override
+    public int hashCode() {
+      return Objects.hash(fD);
+    }
+    
+    @Override
+    public boolean equals(final Object obj) {
+      if (this == obj)
+          return true;
+      if (obj == null) {
+          return false;
+      }
+      if ((obj instanceof Dir.Match)) {
+          Dir.Match other = (Dir.Match) obj;
+          return Objects.equals(fD, other.fD);
+      } 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 Dir specification() {
+      return Dir.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 Dir.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 pD the fixed value of pattern parameter d, or null if not bound.
+     * @return the new, mutable (partial) match object.
+     * 
+     */
+    public static Dir.Match newMutableMatch(final hu.bme.mit.inf.dslreasoner.domains.alloyexamples.Filesystem.Dir pD) {
+      return new Mutable(pD);
+    }
+    
+    /**
+     * 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 pD the fixed value of pattern parameter d, or null if not bound.
+     * @return the (partial) match object.
+     * 
+     */
+    public static Dir.Match newMatch(final hu.bme.mit.inf.dslreasoner.domains.alloyexamples.Filesystem.Dir pD) {
+      return new Immutable(pD);
+    }
+    
+    private static final class Mutable extends Dir.Match {
+      Mutable(final hu.bme.mit.inf.dslreasoner.domains.alloyexamples.Filesystem.Dir pD) {
+        super(pD);
+      }
+      
+      @Override
+      public boolean isMutable() {
+        return true;
+      }
+    }
+    
+    private static final class Immutable extends Dir.Match {
+      Immutable(final hu.bme.mit.inf.dslreasoner.domains.alloyexamples.Filesystem.Dir pD) {
+        super(pD);
+      }
+      
+      @Override
+      public boolean isMutable() {
+        return false;
+      }
+    }
+  }
+  
+  /**
+   * Generated pattern matcher API of the hu.bme.mit.inf.dslreasoner.domains.alloyexamples.dir 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 dir(d: Dir) {
+   *    Dir(d);
+   * }
+   * </pre></code>
+   * 
+   * @see Match
+   * @see Dir
+   * 
+   */
+  public static class Matcher extends BaseMatcher<Dir.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 Dir.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 Dir.Matcher create() {
+      return new Matcher();
+    }
+    
+    private static final int POSITION_D = 0;
+    
+    private static final Logger LOGGER = ViatraQueryLoggingUtil.getLogger(Dir.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 pD the fixed value of pattern parameter d, or null if not bound.
+     * @return matches represented as a Match object.
+     * 
+     */
+    public Collection<Dir.Match> getAllMatches(final hu.bme.mit.inf.dslreasoner.domains.alloyexamples.Filesystem.Dir pD) {
+      return rawStreamAllMatches(new Object[]{pD}).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 pD the fixed value of pattern parameter d, or null if not bound.
+     * @return a stream of matches represented as a Match object.
+     * 
+     */
+    public Stream<Dir.Match> streamAllMatches(final hu.bme.mit.inf.dslreasoner.domains.alloyexamples.Filesystem.Dir pD) {
+      return rawStreamAllMatches(new Object[]{pD});
+    }
+    
+    /**
+     * 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 pD the fixed value of pattern parameter d, or null if not bound.
+     * @return a match represented as a Match object, or null if no match is found.
+     * 
+     */
+    public Optional<Dir.Match> getOneArbitraryMatch(final hu.bme.mit.inf.dslreasoner.domains.alloyexamples.Filesystem.Dir pD) {
+      return rawGetOneArbitraryMatch(new Object[]{pD});
+    }
+    
+    /**
+     * 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 pD the fixed value of pattern parameter d, or null if not bound.
+     * @return true if the input is a valid (partial) match of the pattern.
+     * 
+     */
+    public boolean hasMatch(final hu.bme.mit.inf.dslreasoner.domains.alloyexamples.Filesystem.Dir pD) {
+      return rawHasMatch(new Object[]{pD});
+    }
+    
+    /**
+     * Returns the number of all matches of the pattern that conform to the given fixed values of some parameters.
+     * @param pD the fixed value of pattern parameter d, or null if not bound.
+     * @return the number of pattern matches found.
+     * 
+     */
+    public int countMatches(final hu.bme.mit.inf.dslreasoner.domains.alloyexamples.Filesystem.Dir pD) {
+      return rawCountMatches(new Object[]{pD});
+    }
+    
+    /**
+     * 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 pD the fixed value of pattern parameter d, 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 hu.bme.mit.inf.dslreasoner.domains.alloyexamples.Filesystem.Dir pD, final Consumer<? super Dir.Match> processor) {
+      return rawForOneArbitraryMatch(new Object[]{pD}, 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 pD the fixed value of pattern parameter d, or null if not bound.
+     * @return the (partial) match object.
+     * 
+     */
+    public Dir.Match newMatch(final hu.bme.mit.inf.dslreasoner.domains.alloyexamples.Filesystem.Dir pD) {
+      return Dir.Match.newMatch(pD);
+    }
+    
+    /**
+     * Retrieve the set of values that occur in matches for d.
+     * @return the Set of all values or empty set if there are no matches
+     * 
+     */
+    protected Stream<hu.bme.mit.inf.dslreasoner.domains.alloyexamples.Filesystem.Dir> rawStreamAllValuesOfd(final Object[] parameters) {
+      return rawStreamAllValues(POSITION_D, parameters).map(hu.bme.mit.inf.dslreasoner.domains.alloyexamples.Filesystem.Dir.class::cast);
+    }
+    
+    /**
+     * Retrieve the set of values that occur in matches for d.
+     * @return the Set of all values or empty set if there are no matches
+     * 
+     */
+    public Set<hu.bme.mit.inf.dslreasoner.domains.alloyexamples.Filesystem.Dir> getAllValuesOfd() {
+      return rawStreamAllValuesOfd(emptyArray()).collect(Collectors.toSet());
+    }
+    
+    /**
+     * Retrieve the set of values that occur in matches for d.
+     * @return the Set of all values or empty set if there are no matches
+     * 
+     */
+    public Stream<hu.bme.mit.inf.dslreasoner.domains.alloyexamples.Filesystem.Dir> streamAllValuesOfd() {
+      return rawStreamAllValuesOfd(emptyArray());
+    }
+    
+    @Override
+    protected Dir.Match tupleToMatch(final Tuple t) {
+      try {
+          return Dir.Match.newMatch((hu.bme.mit.inf.dslreasoner.domains.alloyexamples.Filesystem.Dir) t.get(POSITION_D));
+      } catch(ClassCastException e) {
+          LOGGER.error("Element(s) in tuple not properly typed!",e);
+          return null;
+      }
+    }
+    
+    @Override
+    protected Dir.Match arrayToMatch(final Object[] match) {
+      try {
+          return Dir.Match.newMatch((hu.bme.mit.inf.dslreasoner.domains.alloyexamples.Filesystem.Dir) match[POSITION_D]);
+      } catch(ClassCastException e) {
+          LOGGER.error("Element(s) in array not properly typed!",e);
+          return null;
+      }
+    }
+    
+    @Override
+    protected Dir.Match arrayToMatchMutable(final Object[] match) {
+      try {
+          return Dir.Match.newMutableMatch((hu.bme.mit.inf.dslreasoner.domains.alloyexamples.Filesystem.Dir) match[POSITION_D]);
+      } 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<Dir.Matcher> querySpecification() {
+      return Dir.instance();
+    }
+  }
+  
+  private Dir() {
+    super(GeneratedPQuery.INSTANCE);
+  }
+  
+  /**
+   * @return the singleton instance of the query specification
+   * @throws ViatraQueryRuntimeException if the pattern definition could not be loaded
+   * 
+   */
+  public static Dir instance() {
+    try{
+        return LazyHolder.INSTANCE;
+    } catch (ExceptionInInitializerError err) {
+        throw processInitializerError(err);
+    }
+  }
+  
+  @Override
+  protected Dir.Matcher instantiate(final ViatraQueryEngine engine) {
+    return Dir.Matcher.on(engine);
+  }
+  
+  @Override
+  public Dir.Matcher instantiate() {
+    return Dir.Matcher.create();
+  }
+  
+  @Override
+  public Dir.Match newEmptyMatch() {
+    return Dir.Match.newEmptyMatch();
+  }
+  
+  @Override
+  public Dir.Match newMatch(final Object... parameters) {
+    return Dir.Match.newMatch((hu.bme.mit.inf.dslreasoner.domains.alloyexamples.Filesystem.Dir) parameters[0]);
+  }
+  
+  /**
+   * Inner class allowing the singleton instance of {@link JvmGenericType: hu.bme.mit.inf.dslreasoner.domains.alloyexamples.Dir (visibility: PUBLIC, simpleName: Dir, identifier: hu.bme.mit.inf.dslreasoner.domains.alloyexamples.Dir, deprecated: <unset>) (abstract: false, static: false, final: true, packageName: hu.bme.mit.inf.dslreasoner.domains.alloyexamples) (interface: false, strictFloatingPoint: false, anonymous: false)} to be created 
+   *     <b>not</b> at the class load time of the outer class, 
+   *     but rather at the first call to {@link JvmGenericType: hu.bme.mit.inf.dslreasoner.domains.alloyexamples.Dir (visibility: PUBLIC, simpleName: Dir, identifier: hu.bme.mit.inf.dslreasoner.domains.alloyexamples.Dir, deprecated: <unset>) (abstract: false, static: false, final: true, packageName: hu.bme.mit.inf.dslreasoner.domains.alloyexamples) (interface: false, strictFloatingPoint: false, anonymous: false)#instance()}.
+   * 
+   * <p> This workaround is required e.g. to support recursion.
+   * 
+   */
+  private static class LazyHolder {
+    private static final Dir INSTANCE = new Dir();
+    
+    /**
+     * 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 Dir.GeneratedPQuery INSTANCE = new GeneratedPQuery();
+    
+    private final PParameter parameter_d = new PParameter("d", "hu.bme.mit.inf.dslreasoner.domains.alloyexamples.Filesystem.Dir", new EClassTransitiveInstancesKey((EClass)getClassifierLiteralSafe("FS", "Dir")), PParameterDirection.INOUT);
+    
+    private final List<PParameter> parameters = Arrays.asList(parameter_d);
+    
+    private GeneratedPQuery() {
+      super(PVisibility.PUBLIC);
+    }
+    
+    @Override
+    public String getFullyQualifiedName() {
+      return "hu.bme.mit.inf.dslreasoner.domains.alloyexamples.dir";
+    }
+    
+    @Override
+    public List<String> getParameterNames() {
+      return Arrays.asList("d");
+    }
+    
+    @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_d = body.getOrCreateVariableByName("d");
+          new TypeConstraint(body, Tuples.flatTupleOf(var_d), new EClassTransitiveInstancesKey((EClass)getClassifierLiteral("FS", "Dir")));
+          body.setSymbolicParameters(Arrays.<ExportedParameter>asList(
+             new ExportedParameter(body, var_d, parameter_d)
+          ));
+          //    Dir(d)
+          new TypeConstraint(body, Tuples.flatTupleOf(var_d), new EClassTransitiveInstancesKey((EClass)getClassifierLiteral("FS", "Dir")));
+          bodies.add(body);
+      }
+      return bodies;
+    }
+  }
+}
diff --git a/Domains/hu.bme.mit.inf.dslreasoner.domains.alloyexamples/src-gen/hu/bme/mit/inf/dslreasoner/domains/alloyexamples/Live.java b/Domains/hu.bme.mit.inf.dslreasoner.domains.alloyexamples/src-gen/hu/bme/mit/inf/dslreasoner/domains/alloyexamples/Live.java
index ae0f0c58..14a4c5c0 100644
--- a/Domains/hu.bme.mit.inf.dslreasoner.domains.alloyexamples/src-gen/hu/bme/mit/inf/dslreasoner/domains/alloyexamples/Live.java
+++ b/Domains/hu.bme.mit.inf.dslreasoner.domains.alloyexamples/src-gen/hu/bme/mit/inf/dslreasoner/domains/alloyexamples/Live.java
@@ -695,7 +695,7 @@ public final class Live extends BaseGeneratedEMFQuerySpecification<Live.Matcher>
           new TypeConstraint(body, Tuples.flatTupleOf(var_this), new EClassTransitiveInstancesKey((EClass)getClassifierLiteral("FS", "FileSystem")));
           PVariable var__virtual_0_ = body.getOrCreateVariableByName(".virtual{0}");
           new TypeConstraint(body, Tuples.flatTupleOf(var_this, var__virtual_0_), new EStructuralFeatureInstancesKey(getFeatureLiteral("FS", "FileSystem", "root")));
-          new TypeConstraint(body, Tuples.flatTupleOf(var__virtual_0_), new EClassTransitiveInstancesKey((EClass)getClassifierLiteral("FS", "Dir")));
+          new TypeConstraint(body, Tuples.flatTupleOf(var__virtual_0_), new EClassTransitiveInstancesKey((EClass)getClassifierLiteral("FS", "FSObject")));
           new Equality(body, var__virtual_0_, var_l);
           bodies.add(body);
       }
@@ -714,7 +714,7 @@ public final class Live extends BaseGeneratedEMFQuerySpecification<Live.Matcher>
           new TypeConstraint(body, Tuples.flatTupleOf(var_this), new EClassTransitiveInstancesKey((EClass)getClassifierLiteral("FS", "FileSystem")));
           PVariable var__virtual_0_ = body.getOrCreateVariableByName(".virtual{0}");
           new TypeConstraint(body, Tuples.flatTupleOf(var_this, var__virtual_0_), new EStructuralFeatureInstancesKey(getFeatureLiteral("FS", "FileSystem", "root")));
-          new TypeConstraint(body, Tuples.flatTupleOf(var__virtual_0_), new EClassTransitiveInstancesKey((EClass)getClassifierLiteral("FS", "Dir")));
+          new TypeConstraint(body, Tuples.flatTupleOf(var__virtual_0_), new EClassTransitiveInstancesKey((EClass)getClassifierLiteral("FS", "FSObject")));
           new Equality(body, var__virtual_0_, var_root);
           //    find patternContent+(root,l)
           new BinaryTransitiveClosure(body, Tuples.flatTupleOf(var_root, var_l), PatternContent.instance().getInternalQueryRepresentation());
diff --git a/Domains/hu.bme.mit.inf.dslreasoner.domains.alloyexamples/src-gen/hu/bme/mit/inf/dslreasoner/domains/alloyexamples/PatternContent.java b/Domains/hu.bme.mit.inf.dslreasoner.domains.alloyexamples/src-gen/hu/bme/mit/inf/dslreasoner/domains/alloyexamples/PatternContent.java
index 690d3e27..5410b693 100644
--- a/Domains/hu.bme.mit.inf.dslreasoner.domains.alloyexamples/src-gen/hu/bme/mit/inf/dslreasoner/domains/alloyexamples/PatternContent.java
+++ b/Domains/hu.bme.mit.inf.dslreasoner.domains.alloyexamples/src-gen/hu/bme/mit/inf/dslreasoner/domains/alloyexamples/PatternContent.java
@@ -3,6 +3,7 @@
  */
 package hu.bme.mit.inf.dslreasoner.domains.alloyexamples;
 
+import hu.bme.mit.inf.dslreasoner.domains.alloyexamples.Filesystem.Dir;
 import hu.bme.mit.inf.dslreasoner.domains.alloyexamples.Filesystem.FSObject;
 import java.util.Arrays;
 import java.util.Collection;
@@ -43,7 +44,7 @@ import org.eclipse.viatra.query.runtime.util.ViatraQueryLoggingUtil;
  * 
  * <p>Original source:
  *         <code><pre>
- *         pattern patternContent(o1: FSObject, o2: FSObject) {
+ *         pattern patternContent(o1: Dir, o2: FSObject) {
  *              Dir.contents(o1,o2);
  *         }
  * </pre></code>
@@ -67,13 +68,13 @@ public final class PatternContent extends BaseGeneratedEMFQuerySpecification<Pat
    * 
    */
   public static abstract class Match extends BasePatternMatch {
-    private FSObject fO1;
+    private Dir fO1;
     
     private FSObject fO2;
     
     private static List<String> parameterNames = makeImmutableList("o1", "o2");
     
-    private Match(final FSObject pO1, final FSObject pO2) {
+    private Match(final Dir pO1, final FSObject pO2) {
       this.fO1 = pO1;
       this.fO2 = pO2;
     }
@@ -85,7 +86,7 @@ public final class PatternContent extends BaseGeneratedEMFQuerySpecification<Pat
       return null;
     }
     
-    public FSObject getO1() {
+    public Dir getO1() {
       return this.fO1;
     }
     
@@ -97,7 +98,7 @@ public final class PatternContent extends BaseGeneratedEMFQuerySpecification<Pat
     public boolean set(final String parameterName, final Object newValue) {
       if (!isMutable()) throw new java.lang.UnsupportedOperationException();
       if ("o1".equals(parameterName) ) {
-          this.fO1 = (FSObject) newValue;
+          this.fO1 = (Dir) newValue;
           return true;
       }
       if ("o2".equals(parameterName) ) {
@@ -107,7 +108,7 @@ public final class PatternContent extends BaseGeneratedEMFQuerySpecification<Pat
       return false;
     }
     
-    public void setO1(final FSObject pO1) {
+    public void setO1(final Dir pO1) {
       if (!isMutable()) throw new java.lang.UnsupportedOperationException();
       this.fO1 = pO1;
     }
@@ -195,7 +196,7 @@ public final class PatternContent extends BaseGeneratedEMFQuerySpecification<Pat
      * @return the new, mutable (partial) match object.
      * 
      */
-    public static PatternContent.Match newMutableMatch(final FSObject pO1, final FSObject pO2) {
+    public static PatternContent.Match newMutableMatch(final Dir pO1, final FSObject pO2) {
       return new Mutable(pO1, pO2);
     }
     
@@ -208,12 +209,12 @@ public final class PatternContent extends BaseGeneratedEMFQuerySpecification<Pat
      * @return the (partial) match object.
      * 
      */
-    public static PatternContent.Match newMatch(final FSObject pO1, final FSObject pO2) {
+    public static PatternContent.Match newMatch(final Dir pO1, final FSObject pO2) {
       return new Immutable(pO1, pO2);
     }
     
     private static final class Mutable extends PatternContent.Match {
-      Mutable(final FSObject pO1, final FSObject pO2) {
+      Mutable(final Dir pO1, final FSObject pO2) {
         super(pO1, pO2);
       }
       
@@ -224,7 +225,7 @@ public final class PatternContent extends BaseGeneratedEMFQuerySpecification<Pat
     }
     
     private static final class Immutable extends PatternContent.Match {
-      Immutable(final FSObject pO1, final FSObject pO2) {
+      Immutable(final Dir pO1, final FSObject pO2) {
         super(pO1, pO2);
       }
       
@@ -246,7 +247,7 @@ public final class PatternContent extends BaseGeneratedEMFQuerySpecification<Pat
    * 
    * <p>Original source:
    * <code><pre>
-   * pattern patternContent(o1: FSObject, o2: FSObject) {
+   * pattern patternContent(o1: Dir, o2: FSObject) {
    *    Dir.contents(o1,o2);
    * }
    * </pre></code>
@@ -308,7 +309,7 @@ public final class PatternContent extends BaseGeneratedEMFQuerySpecification<Pat
      * @return matches represented as a Match object.
      * 
      */
-    public Collection<PatternContent.Match> getAllMatches(final FSObject pO1, final FSObject pO2) {
+    public Collection<PatternContent.Match> getAllMatches(final Dir pO1, final FSObject pO2) {
       return rawStreamAllMatches(new Object[]{pO1, pO2}).collect(Collectors.toSet());
     }
     
@@ -323,7 +324,7 @@ public final class PatternContent extends BaseGeneratedEMFQuerySpecification<Pat
      * @return a stream of matches represented as a Match object.
      * 
      */
-    public Stream<PatternContent.Match> streamAllMatches(final FSObject pO1, final FSObject pO2) {
+    public Stream<PatternContent.Match> streamAllMatches(final Dir pO1, final FSObject pO2) {
       return rawStreamAllMatches(new Object[]{pO1, pO2});
     }
     
@@ -335,7 +336,7 @@ public final class PatternContent extends BaseGeneratedEMFQuerySpecification<Pat
      * @return a match represented as a Match object, or null if no match is found.
      * 
      */
-    public Optional<PatternContent.Match> getOneArbitraryMatch(final FSObject pO1, final FSObject pO2) {
+    public Optional<PatternContent.Match> getOneArbitraryMatch(final Dir pO1, final FSObject pO2) {
       return rawGetOneArbitraryMatch(new Object[]{pO1, pO2});
     }
     
@@ -347,7 +348,7 @@ public final class PatternContent extends BaseGeneratedEMFQuerySpecification<Pat
      * @return true if the input is a valid (partial) match of the pattern.
      * 
      */
-    public boolean hasMatch(final FSObject pO1, final FSObject pO2) {
+    public boolean hasMatch(final Dir pO1, final FSObject pO2) {
       return rawHasMatch(new Object[]{pO1, pO2});
     }
     
@@ -358,7 +359,7 @@ public final class PatternContent extends BaseGeneratedEMFQuerySpecification<Pat
      * @return the number of pattern matches found.
      * 
      */
-    public int countMatches(final FSObject pO1, final FSObject pO2) {
+    public int countMatches(final Dir pO1, final FSObject pO2) {
       return rawCountMatches(new Object[]{pO1, pO2});
     }
     
@@ -371,7 +372,7 @@ public final class PatternContent extends BaseGeneratedEMFQuerySpecification<Pat
      * @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 FSObject pO1, final FSObject pO2, final Consumer<? super PatternContent.Match> processor) {
+    public boolean forOneArbitraryMatch(final Dir pO1, final FSObject pO2, final Consumer<? super PatternContent.Match> processor) {
       return rawForOneArbitraryMatch(new Object[]{pO1, pO2}, processor);
     }
     
@@ -384,7 +385,7 @@ public final class PatternContent extends BaseGeneratedEMFQuerySpecification<Pat
      * @return the (partial) match object.
      * 
      */
-    public PatternContent.Match newMatch(final FSObject pO1, final FSObject pO2) {
+    public PatternContent.Match newMatch(final Dir pO1, final FSObject pO2) {
       return PatternContent.Match.newMatch(pO1, pO2);
     }
     
@@ -393,8 +394,8 @@ public final class PatternContent extends BaseGeneratedEMFQuerySpecification<Pat
      * @return the Set of all values or empty set if there are no matches
      * 
      */
-    protected Stream<FSObject> rawStreamAllValuesOfo1(final Object[] parameters) {
-      return rawStreamAllValues(POSITION_O1, parameters).map(FSObject.class::cast);
+    protected Stream<Dir> rawStreamAllValuesOfo1(final Object[] parameters) {
+      return rawStreamAllValues(POSITION_O1, parameters).map(Dir.class::cast);
     }
     
     /**
@@ -402,7 +403,7 @@ public final class PatternContent extends BaseGeneratedEMFQuerySpecification<Pat
      * @return the Set of all values or empty set if there are no matches
      * 
      */
-    public Set<FSObject> getAllValuesOfo1() {
+    public Set<Dir> getAllValuesOfo1() {
       return rawStreamAllValuesOfo1(emptyArray()).collect(Collectors.toSet());
     }
     
@@ -411,7 +412,7 @@ public final class PatternContent extends BaseGeneratedEMFQuerySpecification<Pat
      * @return the Set of all values or empty set if there are no matches
      * 
      */
-    public Stream<FSObject> streamAllValuesOfo1() {
+    public Stream<Dir> streamAllValuesOfo1() {
       return rawStreamAllValuesOfo1(emptyArray());
     }
     
@@ -425,7 +426,7 @@ public final class PatternContent extends BaseGeneratedEMFQuerySpecification<Pat
      * @return the Stream of all values or empty set if there are no matches
      * 
      */
-    public Stream<FSObject> streamAllValuesOfo1(final PatternContent.Match partialMatch) {
+    public Stream<Dir> streamAllValuesOfo1(final PatternContent.Match partialMatch) {
       return rawStreamAllValuesOfo1(partialMatch.toArray());
     }
     
@@ -439,7 +440,7 @@ public final class PatternContent extends BaseGeneratedEMFQuerySpecification<Pat
      * @return the Stream of all values or empty set if there are no matches
      * 
      */
-    public Stream<FSObject> streamAllValuesOfo1(final FSObject pO2) {
+    public Stream<Dir> streamAllValuesOfo1(final FSObject pO2) {
       return rawStreamAllValuesOfo1(new Object[]{null, pO2});
     }
     
@@ -448,7 +449,7 @@ public final class PatternContent extends BaseGeneratedEMFQuerySpecification<Pat
      * @return the Set of all values or empty set if there are no matches
      * 
      */
-    public Set<FSObject> getAllValuesOfo1(final PatternContent.Match partialMatch) {
+    public Set<Dir> getAllValuesOfo1(final PatternContent.Match partialMatch) {
       return rawStreamAllValuesOfo1(partialMatch.toArray()).collect(Collectors.toSet());
     }
     
@@ -457,7 +458,7 @@ public final class PatternContent extends BaseGeneratedEMFQuerySpecification<Pat
      * @return the Set of all values or empty set if there are no matches
      * 
      */
-    public Set<FSObject> getAllValuesOfo1(final FSObject pO2) {
+    public Set<Dir> getAllValuesOfo1(final FSObject pO2) {
       return rawStreamAllValuesOfo1(new Object[]{null, pO2}).collect(Collectors.toSet());
     }
     
@@ -512,7 +513,7 @@ public final class PatternContent extends BaseGeneratedEMFQuerySpecification<Pat
      * @return the Stream of all values or empty set if there are no matches
      * 
      */
-    public Stream<FSObject> streamAllValuesOfo2(final FSObject pO1) {
+    public Stream<FSObject> streamAllValuesOfo2(final Dir pO1) {
       return rawStreamAllValuesOfo2(new Object[]{pO1, null});
     }
     
@@ -530,14 +531,14 @@ public final class PatternContent extends BaseGeneratedEMFQuerySpecification<Pat
      * @return the Set of all values or empty set if there are no matches
      * 
      */
-    public Set<FSObject> getAllValuesOfo2(final FSObject pO1) {
+    public Set<FSObject> getAllValuesOfo2(final Dir pO1) {
       return rawStreamAllValuesOfo2(new Object[]{pO1, null}).collect(Collectors.toSet());
     }
     
     @Override
     protected PatternContent.Match tupleToMatch(final Tuple t) {
       try {
-          return PatternContent.Match.newMatch((FSObject) t.get(POSITION_O1), (FSObject) t.get(POSITION_O2));
+          return PatternContent.Match.newMatch((Dir) t.get(POSITION_O1), (FSObject) t.get(POSITION_O2));
       } catch(ClassCastException e) {
           LOGGER.error("Element(s) in tuple not properly typed!",e);
           return null;
@@ -547,7 +548,7 @@ public final class PatternContent extends BaseGeneratedEMFQuerySpecification<Pat
     @Override
     protected PatternContent.Match arrayToMatch(final Object[] match) {
       try {
-          return PatternContent.Match.newMatch((FSObject) match[POSITION_O1], (FSObject) match[POSITION_O2]);
+          return PatternContent.Match.newMatch((Dir) match[POSITION_O1], (FSObject) match[POSITION_O2]);
       } catch(ClassCastException e) {
           LOGGER.error("Element(s) in array not properly typed!",e);
           return null;
@@ -557,7 +558,7 @@ public final class PatternContent extends BaseGeneratedEMFQuerySpecification<Pat
     @Override
     protected PatternContent.Match arrayToMatchMutable(final Object[] match) {
       try {
-          return PatternContent.Match.newMutableMatch((FSObject) match[POSITION_O1], (FSObject) match[POSITION_O2]);
+          return PatternContent.Match.newMutableMatch((Dir) match[POSITION_O1], (FSObject) match[POSITION_O2]);
       } catch(ClassCastException e) {
           LOGGER.error("Element(s) in array not properly typed!",e);
           return null;
@@ -608,7 +609,7 @@ public final class PatternContent extends BaseGeneratedEMFQuerySpecification<Pat
   
   @Override
   public PatternContent.Match newMatch(final Object... parameters) {
-    return PatternContent.Match.newMatch((hu.bme.mit.inf.dslreasoner.domains.alloyexamples.Filesystem.FSObject) parameters[0], (hu.bme.mit.inf.dslreasoner.domains.alloyexamples.Filesystem.FSObject) parameters[1]);
+    return PatternContent.Match.newMatch((hu.bme.mit.inf.dslreasoner.domains.alloyexamples.Filesystem.Dir) parameters[0], (hu.bme.mit.inf.dslreasoner.domains.alloyexamples.Filesystem.FSObject) parameters[1]);
   }
   
   /**
@@ -640,7 +641,7 @@ public final class PatternContent extends BaseGeneratedEMFQuerySpecification<Pat
   private static class GeneratedPQuery extends BaseGeneratedEMFPQuery {
     private static final PatternContent.GeneratedPQuery INSTANCE = new GeneratedPQuery();
     
-    private final PParameter parameter_o1 = new PParameter("o1", "hu.bme.mit.inf.dslreasoner.domains.alloyexamples.Filesystem.FSObject", new EClassTransitiveInstancesKey((EClass)getClassifierLiteralSafe("FS", "FSObject")), PParameterDirection.INOUT);
+    private final PParameter parameter_o1 = new PParameter("o1", "hu.bme.mit.inf.dslreasoner.domains.alloyexamples.Filesystem.Dir", new EClassTransitiveInstancesKey((EClass)getClassifierLiteralSafe("FS", "Dir")), PParameterDirection.INOUT);
     
     private final PParameter parameter_o2 = new PParameter("o2", "hu.bme.mit.inf.dslreasoner.domains.alloyexamples.Filesystem.FSObject", new EClassTransitiveInstancesKey((EClass)getClassifierLiteralSafe("FS", "FSObject")), PParameterDirection.INOUT);
     
@@ -673,7 +674,7 @@ public final class PatternContent extends BaseGeneratedEMFQuerySpecification<Pat
           PBody body = new PBody(this);
           PVariable var_o1 = body.getOrCreateVariableByName("o1");
           PVariable var_o2 = body.getOrCreateVariableByName("o2");
-          new TypeConstraint(body, Tuples.flatTupleOf(var_o1), new EClassTransitiveInstancesKey((EClass)getClassifierLiteral("FS", "FSObject")));
+          new TypeConstraint(body, Tuples.flatTupleOf(var_o1), new EClassTransitiveInstancesKey((EClass)getClassifierLiteral("FS", "Dir")));
           new TypeConstraint(body, Tuples.flatTupleOf(var_o2), new EClassTransitiveInstancesKey((EClass)getClassifierLiteral("FS", "FSObject")));
           body.setSymbolicParameters(Arrays.<ExportedParameter>asList(
              new ExportedParameter(body, var_o1, parameter_o1),
diff --git a/Domains/hu.bme.mit.inf.dslreasoner.domains.alloyexamples/src-gen/hu/bme/mit/inf/dslreasoner/domains/alloyexamples/RootIsNotDir.java b/Domains/hu.bme.mit.inf.dslreasoner.domains.alloyexamples/src-gen/hu/bme/mit/inf/dslreasoner/domains/alloyexamples/RootIsNotDir.java
new file mode 100644
index 00000000..22c31158
--- /dev/null
+++ b/Domains/hu.bme.mit.inf.dslreasoner.domains.alloyexamples/src-gen/hu/bme/mit/inf/dslreasoner/domains/alloyexamples/RootIsNotDir.java
@@ -0,0 +1,560 @@
+/**
+ * Generated from platform:/resource/hu.bme.mit.inf.dslreasoner.domains.alloyexamples/patterns/hu/bme/mit/inf/dslreasoner/domains/alloyexamples/FileSystem.vql
+ */
+package hu.bme.mit.inf.dslreasoner.domains.alloyexamples;
+
+import hu.bme.mit.inf.dslreasoner.domains.alloyexamples.Dir;
+import hu.bme.mit.inf.dslreasoner.domains.alloyexamples.Filesystem.FileSystem;
+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.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;
+
+/**
+ * A pattern-specific query specification that can instantiate Matcher in a type-safe way.
+ * 
+ * <p>Original source:
+ *         <code><pre>
+ *         {@literal @}Constraint(key={fs}, severity="error", message="error")
+ *         pattern rootIsNotDir(fs: FileSystem) {
+ *              FileSystem.root(fs, root);
+ *              neg find dir(root);
+ *         }
+ * </pre></code>
+ * 
+ * @see Matcher
+ * @see Match
+ * 
+ */
+@SuppressWarnings("all")
+public final class RootIsNotDir extends BaseGeneratedEMFQuerySpecification<RootIsNotDir.Matcher> {
+  /**
+   * Pattern-specific match representation of the hu.bme.mit.inf.dslreasoner.domains.alloyexamples.rootIsNotDir 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 FileSystem fFs;
+    
+    private static List<String> parameterNames = makeImmutableList("fs");
+    
+    private Match(final FileSystem pFs) {
+      this.fFs = pFs;
+    }
+    
+    @Override
+    public Object get(final String parameterName) {
+      if ("fs".equals(parameterName)) return this.fFs;
+      return null;
+    }
+    
+    public FileSystem getFs() {
+      return this.fFs;
+    }
+    
+    @Override
+    public boolean set(final String parameterName, final Object newValue) {
+      if (!isMutable()) throw new java.lang.UnsupportedOperationException();
+      if ("fs".equals(parameterName) ) {
+          this.fFs = (FileSystem) newValue;
+          return true;
+      }
+      return false;
+    }
+    
+    public void setFs(final FileSystem pFs) {
+      if (!isMutable()) throw new java.lang.UnsupportedOperationException();
+      this.fFs = pFs;
+    }
+    
+    @Override
+    public String patternName() {
+      return "hu.bme.mit.inf.dslreasoner.domains.alloyexamples.rootIsNotDir";
+    }
+    
+    @Override
+    public List<String> parameterNames() {
+      return RootIsNotDir.Match.parameterNames;
+    }
+    
+    @Override
+    public Object[] toArray() {
+      return new Object[]{fFs};
+    }
+    
+    @Override
+    public RootIsNotDir.Match toImmutable() {
+      return isMutable() ? newMatch(fFs) : this;
+    }
+    
+    @Override
+    public String prettyPrint() {
+      StringBuilder result = new StringBuilder();
+      result.append("\"fs\"=" + prettyPrintValue(fFs));
+      return result.toString();
+    }
+    
+    @Override
+    public int hashCode() {
+      return Objects.hash(fFs);
+    }
+    
+    @Override
+    public boolean equals(final Object obj) {
+      if (this == obj)
+          return true;
+      if (obj == null) {
+          return false;
+      }
+      if ((obj instanceof RootIsNotDir.Match)) {
+          RootIsNotDir.Match other = (RootIsNotDir.Match) obj;
+          return Objects.equals(fFs, other.fFs);
+      } 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 RootIsNotDir specification() {
+      return RootIsNotDir.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 RootIsNotDir.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 pFs the fixed value of pattern parameter fs, or null if not bound.
+     * @return the new, mutable (partial) match object.
+     * 
+     */
+    public static RootIsNotDir.Match newMutableMatch(final FileSystem pFs) {
+      return new Mutable(pFs);
+    }
+    
+    /**
+     * 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 pFs the fixed value of pattern parameter fs, or null if not bound.
+     * @return the (partial) match object.
+     * 
+     */
+    public static RootIsNotDir.Match newMatch(final FileSystem pFs) {
+      return new Immutable(pFs);
+    }
+    
+    private static final class Mutable extends RootIsNotDir.Match {
+      Mutable(final FileSystem pFs) {
+        super(pFs);
+      }
+      
+      @Override
+      public boolean isMutable() {
+        return true;
+      }
+    }
+    
+    private static final class Immutable extends RootIsNotDir.Match {
+      Immutable(final FileSystem pFs) {
+        super(pFs);
+      }
+      
+      @Override
+      public boolean isMutable() {
+        return false;
+      }
+    }
+  }
+  
+  /**
+   * Generated pattern matcher API of the hu.bme.mit.inf.dslreasoner.domains.alloyexamples.rootIsNotDir 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(key={fs}, severity="error", message="error")
+   * pattern rootIsNotDir(fs: FileSystem) {
+   *    FileSystem.root(fs, root);
+   *    neg find dir(root);
+   * }
+   * </pre></code>
+   * 
+   * @see Match
+   * @see RootIsNotDir
+   * 
+   */
+  public static class Matcher extends BaseMatcher<RootIsNotDir.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 RootIsNotDir.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 RootIsNotDir.Matcher create() {
+      return new Matcher();
+    }
+    
+    private static final int POSITION_FS = 0;
+    
+    private static final Logger LOGGER = ViatraQueryLoggingUtil.getLogger(RootIsNotDir.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 pFs the fixed value of pattern parameter fs, or null if not bound.
+     * @return matches represented as a Match object.
+     * 
+     */
+    public Collection<RootIsNotDir.Match> getAllMatches(final FileSystem pFs) {
+      return rawStreamAllMatches(new Object[]{pFs}).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 pFs the fixed value of pattern parameter fs, or null if not bound.
+     * @return a stream of matches represented as a Match object.
+     * 
+     */
+    public Stream<RootIsNotDir.Match> streamAllMatches(final FileSystem pFs) {
+      return rawStreamAllMatches(new Object[]{pFs});
+    }
+    
+    /**
+     * 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 pFs the fixed value of pattern parameter fs, or null if not bound.
+     * @return a match represented as a Match object, or null if no match is found.
+     * 
+     */
+    public Optional<RootIsNotDir.Match> getOneArbitraryMatch(final FileSystem pFs) {
+      return rawGetOneArbitraryMatch(new Object[]{pFs});
+    }
+    
+    /**
+     * 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 pFs the fixed value of pattern parameter fs, or null if not bound.
+     * @return true if the input is a valid (partial) match of the pattern.
+     * 
+     */
+    public boolean hasMatch(final FileSystem pFs) {
+      return rawHasMatch(new Object[]{pFs});
+    }
+    
+    /**
+     * Returns the number of all matches of the pattern that conform to the given fixed values of some parameters.
+     * @param pFs the fixed value of pattern parameter fs, or null if not bound.
+     * @return the number of pattern matches found.
+     * 
+     */
+    public int countMatches(final FileSystem pFs) {
+      return rawCountMatches(new Object[]{pFs});
+    }
+    
+    /**
+     * 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 pFs the fixed value of pattern parameter fs, 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 FileSystem pFs, final Consumer<? super RootIsNotDir.Match> processor) {
+      return rawForOneArbitraryMatch(new Object[]{pFs}, 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 pFs the fixed value of pattern parameter fs, or null if not bound.
+     * @return the (partial) match object.
+     * 
+     */
+    public RootIsNotDir.Match newMatch(final FileSystem pFs) {
+      return RootIsNotDir.Match.newMatch(pFs);
+    }
+    
+    /**
+     * Retrieve the set of values that occur in matches for fs.
+     * @return the Set of all values or empty set if there are no matches
+     * 
+     */
+    protected Stream<FileSystem> rawStreamAllValuesOffs(final Object[] parameters) {
+      return rawStreamAllValues(POSITION_FS, parameters).map(FileSystem.class::cast);
+    }
+    
+    /**
+     * Retrieve the set of values that occur in matches for fs.
+     * @return the Set of all values or empty set if there are no matches
+     * 
+     */
+    public Set<FileSystem> getAllValuesOffs() {
+      return rawStreamAllValuesOffs(emptyArray()).collect(Collectors.toSet());
+    }
+    
+    /**
+     * Retrieve the set of values that occur in matches for fs.
+     * @return the Set of all values or empty set if there are no matches
+     * 
+     */
+    public Stream<FileSystem> streamAllValuesOffs() {
+      return rawStreamAllValuesOffs(emptyArray());
+    }
+    
+    @Override
+    protected RootIsNotDir.Match tupleToMatch(final Tuple t) {
+      try {
+          return RootIsNotDir.Match.newMatch((FileSystem) t.get(POSITION_FS));
+      } catch(ClassCastException e) {
+          LOGGER.error("Element(s) in tuple not properly typed!",e);
+          return null;
+      }
+    }
+    
+    @Override
+    protected RootIsNotDir.Match arrayToMatch(final Object[] match) {
+      try {
+          return RootIsNotDir.Match.newMatch((FileSystem) match[POSITION_FS]);
+      } catch(ClassCastException e) {
+          LOGGER.error("Element(s) in array not properly typed!",e);
+          return null;
+      }
+    }
+    
+    @Override
+    protected RootIsNotDir.Match arrayToMatchMutable(final Object[] match) {
+      try {
+          return RootIsNotDir.Match.newMutableMatch((FileSystem) match[POSITION_FS]);
+      } 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<RootIsNotDir.Matcher> querySpecification() {
+      return RootIsNotDir.instance();
+    }
+  }
+  
+  private RootIsNotDir() {
+    super(GeneratedPQuery.INSTANCE);
+  }
+  
+  /**
+   * @return the singleton instance of the query specification
+   * @throws ViatraQueryRuntimeException if the pattern definition could not be loaded
+   * 
+   */
+  public static RootIsNotDir instance() {
+    try{
+        return LazyHolder.INSTANCE;
+    } catch (ExceptionInInitializerError err) {
+        throw processInitializerError(err);
+    }
+  }
+  
+  @Override
+  protected RootIsNotDir.Matcher instantiate(final ViatraQueryEngine engine) {
+    return RootIsNotDir.Matcher.on(engine);
+  }
+  
+  @Override
+  public RootIsNotDir.Matcher instantiate() {
+    return RootIsNotDir.Matcher.create();
+  }
+  
+  @Override
+  public RootIsNotDir.Match newEmptyMatch() {
+    return RootIsNotDir.Match.newEmptyMatch();
+  }
+  
+  @Override
+  public RootIsNotDir.Match newMatch(final Object... parameters) {
+    return RootIsNotDir.Match.newMatch((hu.bme.mit.inf.dslreasoner.domains.alloyexamples.Filesystem.FileSystem) parameters[0]);
+  }
+  
+  /**
+   * Inner class allowing the singleton instance of {@link JvmGenericType: hu.bme.mit.inf.dslreasoner.domains.alloyexamples.RootIsNotDir (visibility: PUBLIC, simpleName: RootIsNotDir, identifier: hu.bme.mit.inf.dslreasoner.domains.alloyexamples.RootIsNotDir, deprecated: <unset>) (abstract: false, static: false, final: true, packageName: hu.bme.mit.inf.dslreasoner.domains.alloyexamples) (interface: false, strictFloatingPoint: false, anonymous: false)} to be created 
+   *     <b>not</b> at the class load time of the outer class, 
+   *     but rather at the first call to {@link JvmGenericType: hu.bme.mit.inf.dslreasoner.domains.alloyexamples.RootIsNotDir (visibility: PUBLIC, simpleName: RootIsNotDir, identifier: hu.bme.mit.inf.dslreasoner.domains.alloyexamples.RootIsNotDir, deprecated: <unset>) (abstract: false, static: false, final: true, packageName: hu.bme.mit.inf.dslreasoner.domains.alloyexamples) (interface: false, strictFloatingPoint: false, anonymous: false)#instance()}.
+   * 
+   * <p> This workaround is required e.g. to support recursion.
+   * 
+   */
+  private static class LazyHolder {
+    private static final RootIsNotDir INSTANCE = new RootIsNotDir();
+    
+    /**
+     * 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 RootIsNotDir.GeneratedPQuery INSTANCE = new GeneratedPQuery();
+    
+    private final PParameter parameter_fs = new PParameter("fs", "hu.bme.mit.inf.dslreasoner.domains.alloyexamples.Filesystem.FileSystem", new EClassTransitiveInstancesKey((EClass)getClassifierLiteralSafe("FS", "FileSystem")), PParameterDirection.INOUT);
+    
+    private final List<PParameter> parameters = Arrays.asList(parameter_fs);
+    
+    private GeneratedPQuery() {
+      super(PVisibility.PUBLIC);
+    }
+    
+    @Override
+    public String getFullyQualifiedName() {
+      return "hu.bme.mit.inf.dslreasoner.domains.alloyexamples.rootIsNotDir";
+    }
+    
+    @Override
+    public List<String> getParameterNames() {
+      return Arrays.asList("fs");
+    }
+    
+    @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_fs = body.getOrCreateVariableByName("fs");
+          PVariable var_root = body.getOrCreateVariableByName("root");
+          new TypeConstraint(body, Tuples.flatTupleOf(var_fs), new EClassTransitiveInstancesKey((EClass)getClassifierLiteral("FS", "FileSystem")));
+          body.setSymbolicParameters(Arrays.<ExportedParameter>asList(
+             new ExportedParameter(body, var_fs, parameter_fs)
+          ));
+          //    FileSystem.root(fs, root)
+          new TypeConstraint(body, Tuples.flatTupleOf(var_fs), new EClassTransitiveInstancesKey((EClass)getClassifierLiteral("FS", "FileSystem")));
+          PVariable var__virtual_0_ = body.getOrCreateVariableByName(".virtual{0}");
+          new TypeConstraint(body, Tuples.flatTupleOf(var_fs, var__virtual_0_), new EStructuralFeatureInstancesKey(getFeatureLiteral("FS", "FileSystem", "root")));
+          new TypeConstraint(body, Tuples.flatTupleOf(var__virtual_0_), new EClassTransitiveInstancesKey((EClass)getClassifierLiteral("FS", "FSObject")));
+          new Equality(body, var__virtual_0_, var_root);
+          //    neg find dir(root)
+          new NegativePatternCall(body, Tuples.flatTupleOf(var_root), Dir.instance().getInternalQueryRepresentation());
+          bodies.add(body);
+      }
+      {
+          PAnnotation annotation = new PAnnotation("Constraint");
+          annotation.addAttribute("key", Arrays.asList(new Object[] {
+                              new ParameterReference("fs")
+                              }));
+          annotation.addAttribute("severity", "error");
+          annotation.addAttribute("message", "error");
+          addAnnotation(annotation);
+      }
+      return bodies;
+    }
+  }
+}