Add scoping tests and simplify implicit nodes

* Do not export implicit nodes to the global scope
* Enum literals must not be quoted
* Plan for the future: unify quoted nodes from the global scope in
  post-processing

7 files changed, 122 insertions, 92 deletions

diff --git a/language/src/main/java/org/eclipse/viatra/solver/language/GenerateProblem.mwe2 b/language/src/main/java/org/eclipse/viatra/solver/language/GenerateProblem.mwe2
index a63681c8..da5e95a4 100644
--- a/language/src/main/java/org/eclipse/viatra/solver/language/GenerateProblem.mwe2
+++ b/language/src/main/java/org/eclipse/viatra/solver/language/GenerateProblem.mwe2
@@ -43,9 +43,7 @@ Workflow {
                         validator = {
                                 generateDeprecationValidation = true
                         }
-                        generator = {
-                                generateXtendStub = true
-                        }
+                        generator = null
                         junitSupport = {
                                 junitVersion = "5"
                         }
diff --git a/language/src/main/java/org/eclipse/viatra/solver/language/Problem.xtext b/language/src/main/java/org/eclipse/viatra/solver/language/Problem.xtext
index 7e253ef5..495f50e4 100644
--- a/language/src/main/java/org/eclipse/viatra/solver/language/Problem.xtext
+++ b/language/src/main/java/org/eclipse/viatra/solver/language/Problem.xtext
@@ -22,7 +22,7 @@ EnumDeclaration:
         ("{" (literals+=EnumLiteral ("," literals+=EnumLiteral)* ("," | ";")?)? "}" | ".");
 
 EnumLiteral returns Node:
-        name=QuotedOrUnquotedId;
+        name=Identifier;
 
 ReferenceDeclaration:
         (containment?="contains" | "refers")?
@@ -129,11 +129,8 @@ ExactMultiplicity:
 UpperBound returns ecore::EInt:
         INT | "*";
 
-QuotedOrUnquotedId:
-        QUOTED_ID | Identifier;
-
 QualifiedName hidden():
-        QUOTED_ID | Identifier ("::" Identifier)* ("::" QUOTED_ID)?;
+        QUOTED_ID | Identifier ("::" Identifier)*;
 
 Identifier:
         ID | "true" | "false" | "e" | "E";
diff --git a/language/src/main/java/org/eclipse/viatra/solver/language/generator/ProblemGenerator.java b/language/src/main/java/org/eclipse/viatra/solver/language/generator/ProblemGenerator.java
new file mode 100644
index 00000000..b6ea3553
--- /dev/null
+++ b/language/src/main/java/org/eclipse/viatra/solver/language/generator/ProblemGenerator.java
@@ -0,0 +1,30 @@
+/*
+ * generated by Xtext 2.26.0.M1
+ */
+package org.eclipse.viatra.solver.language.generator;
+
+import org.eclipse.emf.ecore.resource.Resource;
+import org.eclipse.xtext.generator.AbstractGenerator;
+import org.eclipse.xtext.generator.IFileSystemAccess2;
+import org.eclipse.xtext.generator.IGeneratorContext;
+
+/**
+ * Generates code from your model files on save.
+ * 
+ * See https://www.eclipse.org/Xtext/documentation/303_runtime_concepts.html#code-generation
+ */
+public class ProblemGenerator extends AbstractGenerator {
+
+        @Override
+        public void doGenerate(Resource resource, IFileSystemAccess2 fsa, IGeneratorContext context) {
+//              Iterator<Greeting> filtered = Iterators.filter(resource.getAllContents(), Greeting.class);
+//              Iterator<String> names = Iterators.transform(filtered, new Function<Greeting, String>() {
+//
+//                      @Override
+//                      public String apply(Greeting greeting) {
+//                              return greeting.getName();
+//                      }
+//              });
+//              fsa.generateFile("greetings.txt", "People to greet: " + IteratorExtensions.join(names, ", "));
+        }
+}
diff --git a/language/src/main/java/org/eclipse/viatra/solver/language/generator/ProblemGenerator.xtend b/language/src/main/java/org/eclipse/viatra/solver/language/generator/ProblemGenerator.xtend
deleted file mode 100644
index 0930f244..00000000
--- a/language/src/main/java/org/eclipse/viatra/solver/language/generator/ProblemGenerator.xtend
+++ /dev/null
@@ -1,25 +0,0 @@
-/*
- * generated by Xtext 2.25.0
- */
-package org.eclipse.viatra.solver.language.generator
-
-import org.eclipse.emf.ecore.resource.Resource
-import org.eclipse.xtext.generator.AbstractGenerator
-import org.eclipse.xtext.generator.IFileSystemAccess2
-import org.eclipse.xtext.generator.IGeneratorContext
-
-/**
- * Generates code from your model files on save.
- * 
- * See https://www.eclipse.org/Xtext/documentation/303_runtime_concepts.html#code-generation
- */
-class ProblemGenerator extends AbstractGenerator {
-
-        override void doGenerate(Resource resource, IFileSystemAccess2 fsa, IGeneratorContext context) {
-//              fsa.generateFile('greetings.txt', 'People to greet: ' + 
-//                      resource.allContents
-//                              .filter(Greeting)
-//                              .map[name]
-//                              .join(', '))
-        }
-}
diff --git a/language/src/main/java/org/eclipse/viatra/solver/language/resource/ProblemDerivedStateComputer.java b/language/src/main/java/org/eclipse/viatra/solver/language/resource/ProblemDerivedStateComputer.java
index fc03fa87..56d8ad71 100644
--- a/language/src/main/java/org/eclipse/viatra/solver/language/resource/ProblemDerivedStateComputer.java
+++ b/language/src/main/java/org/eclipse/viatra/solver/language/resource/ProblemDerivedStateComputer.java
@@ -73,13 +73,14 @@ public class ProblemDerivedStateComputer implements IDerivedStateComputer {
 
         protected void installDerivedProblemState(Problem problem, boolean preLinkingPhase) {
                 installNewNodes(problem);
-                if (!preLinkingPhase) {
-                        installDerivedNodes(problem);
-                        for (Statement statement : problem.getStatements()) {
-                                if (statement instanceof PredicateDefinition) {
-                                        PredicateDefinition definition = (PredicateDefinition) statement;
-                                        installDerivedPredicateDefinitionState(definition);
-                                }
+                if (preLinkingPhase) {
+                        return;
+                }
+                Set<String> nodeNames = installDerivedNodes(problem);
+                for (Statement statement : problem.getStatements()) {
+                        if (statement instanceof PredicateDefinition) {
+                                PredicateDefinition definition = (PredicateDefinition) statement;
+                                installDerivedPredicateDefinitionState(definition, nodeNames);
                         }
                 }
         }
@@ -88,7 +89,7 @@ public class ProblemDerivedStateComputer implements IDerivedStateComputer {
                 for (Statement statement : problem.getStatements()) {
                         if (statement instanceof ClassDeclaration) {
                                 ClassDeclaration declaration = (ClassDeclaration) statement;
-                                if (!declaration.isAbstract()) {
+                                if (!declaration.isAbstract() && declaration.getNewNode() == null) {
                                         Node newNode = createNode(NEW_NODE);
                                         declaration.setNewNode(newNode);
                                 }
@@ -96,7 +97,7 @@ public class ProblemDerivedStateComputer implements IDerivedStateComputer {
                 }
         }
 
-        protected void installDerivedNodes(Problem problem) {
+        protected Set<String> installDerivedNodes(Problem problem) {
                 IScope nodeScope = scopeProvider.getScope(problem, ProblemPackage.Literals.ASSERTION__ARGUMENTS);
                 Set<String> nodeNames = new HashSet<>();
                 for (Statement statement : problem.getStatements()) {
@@ -142,6 +143,7 @@ public class ProblemDerivedStateComputer implements IDerivedStateComputer {
                         Node graphNode = createNode(nodeName);
                         grapNodes.add(graphNode);
                 }
+                return nodeNames;
         }
 
         private void addNodeNames(Set<String> nodeNames, IScope nodeScope, EObject eObject, EStructuralFeature feature,
@@ -165,16 +167,17 @@ public class ProblemDerivedStateComputer implements IDerivedStateComputer {
                 return node;
         }
 
-        protected void installDerivedPredicateDefinitionState(PredicateDefinition definition) {
-                Set<String> parameterNames = new HashSet<>();
+        protected void installDerivedPredicateDefinitionState(PredicateDefinition definition, Set<String> nodeNames) {
+                Set<String> knownVariables = new HashSet<>();
+                knownVariables.addAll(nodeNames);
                 for (Parameter parameter : definition.getParameters()) {
                         String name = parameter.getName();
                         if (name != null) {
-                                parameterNames.add(name);
+                                knownVariables.add(name);
                         }
                 }
                 for (Conjunction body : definition.getBodies()) {
-                        installDeriveConjunctionState(body, parameterNames);
+                        installDeriveConjunctionState(body, knownVariables);
                 }
         }
 
@@ -271,10 +274,9 @@ public class ProblemDerivedStateComputer implements IDerivedStateComputer {
         protected void discardDerivedProblemState(Problem problem) {
                 problem.getNodes().clear();
                 for (Statement statement : problem.getStatements()) {
-                        if (statement instanceof ClassDeclaration) {
-                                ClassDeclaration classDeclaration = (ClassDeclaration) statement;
-                                classDeclaration.setNewNode(null);
-                        } else if (statement instanceof PredicateDefinition) {
+                        // We deliberately don't clean up {@link ClassDeclaration#getNewNode()} nodes,
+                        // because they have already been exported to the Xtext index.
+                        if (statement instanceof PredicateDefinition) {
                                 PredicateDefinition definition = (PredicateDefinition) statement;
                                 for (Conjunction body : definition.getBodies()) {
                                         body.getImplicitVariables().clear();
diff --git a/language/src/main/java/org/eclipse/viatra/solver/language/resource/ProblemResourceDescriptionStrategy.java b/language/src/main/java/org/eclipse/viatra/solver/language/resource/ProblemResourceDescriptionStrategy.java
index edb25a1c..4d932a92 100644
--- a/language/src/main/java/org/eclipse/viatra/solver/language/resource/ProblemResourceDescriptionStrategy.java
+++ b/language/src/main/java/org/eclipse/viatra/solver/language/resource/ProblemResourceDescriptionStrategy.java
@@ -24,56 +24,70 @@ public class ProblemResourceDescriptionStrategy extends DefaultResourceDescripti
 
         @Override
         public boolean createEObjectDescriptions(EObject eObject, IAcceptor<IEObjectDescription> acceptor) {
-                if (eObject instanceof Variable) {
+                if (!shouldExport(eObject)) {
                         return false;
                 }
-                if (eObject instanceof NamedElement) {
-                        NamedElement namedElement = (NamedElement) eObject;
-                        String name = namedElement.getName();
-                        if (name == null || name.isEmpty()) {
-                                return true;
-                        }
-                        Problem problem = EcoreUtil2.getContainerOfType(namedElement, Problem.class);
-                        QualifiedName problemQualifiedName = null;
-                        if (problem != null) {
-                                String problemName = problem.getName();
-                                if (problemName != null && !problemName.isEmpty()) {
-                                        problemQualifiedName = qualifiedNameConverter.toQualifiedName(problemName);
-                                }
-                        }
-                        QualifiedName qualifiedName = qualifiedNameConverter.toQualifiedName(namedElement.getName());
-                        boolean nameExported;
-                        if (shouldExportSimpleName(namedElement)) {
-                                acceptEObjectDescription(namedElement, problemQualifiedName, qualifiedName, acceptor);
-                                nameExported = true;
-                        } else {
-                                nameExported = false;
+                if (!(eObject instanceof NamedElement)) {
+                        return true;
+                }
+                NamedElement namedElement = (NamedElement) eObject;
+                String name = namedElement.getName();
+                if (name == null || name.isEmpty()) {
+                        return true;
+                }
+                Problem problem = EcoreUtil2.getContainerOfType(namedElement, Problem.class);
+                QualifiedName problemQualifiedName = null;
+                if (problem != null) {
+                        String problemName = problem.getName();
+                        if (problemName != null && !problemName.isEmpty()) {
+                                problemQualifiedName = qualifiedNameConverter.toQualifiedName(problemName);
                         }
-                        EObject parent = namedElement.eContainer();
-                        while (parent != null && parent != problem) {
-                                if (parent instanceof NamedElement) {
-                                        NamedElement namedParent = (NamedElement) parent;
-                                        String parentName = namedParent.getName();
-                                        if (parentName != null || !name.isEmpty()) {
-                                                QualifiedName parentQualifiedName = qualifiedNameConverter.toQualifiedName(parentName);
-                                                qualifiedName = parentQualifiedName.append(qualifiedName);
-                                                if (shouldExportSimpleName(parent)) {
-                                                        acceptEObjectDescription(namedElement, problemQualifiedName, qualifiedName, acceptor);
-                                                        nameExported = true;
-                                                } else {
-                                                        nameExported = false;
-                                                }
+                }
+                QualifiedName qualifiedName = qualifiedNameConverter.toQualifiedName(namedElement.getName());
+                boolean nameExported;
+                if (shouldExportSimpleName(namedElement)) {
+                        acceptEObjectDescription(namedElement, problemQualifiedName, qualifiedName, acceptor);
+                        nameExported = true;
+                } else {
+                        nameExported = false;
+                }
+                EObject parent = namedElement.eContainer();
+                while (parent != null && parent != problem) {
+                        if (parent instanceof NamedElement) {
+                                NamedElement namedParent = (NamedElement) parent;
+                                String parentName = namedParent.getName();
+                                if (parentName != null || !name.isEmpty()) {
+                                        QualifiedName parentQualifiedName = qualifiedNameConverter.toQualifiedName(parentName);
+                                        qualifiedName = parentQualifiedName.append(qualifiedName);
+                                        if (shouldExportSimpleName(namedParent)) {
+                                                acceptEObjectDescription(namedElement, problemQualifiedName, qualifiedName, acceptor);
+                                                nameExported = true;
+                                        } else {
+                                                nameExported = false;
                                         }
                                 }
-                                parent = parent.eContainer();
-                        }
-                        if (!nameExported) {
-                                acceptEObjectDescription(namedElement, problemQualifiedName, qualifiedName, acceptor);
                         }
+                        parent = parent.eContainer();
+                }
+                if (!nameExported) {
+                        acceptEObjectDescription(namedElement, problemQualifiedName, qualifiedName, acceptor);
                 }
                 return true;
         }
 
+        protected boolean shouldExport(EObject eObject) {
+                if (eObject instanceof Variable) {
+                        // Variables are always private to the containing predicate definition.
+                        return false;
+                }
+                if (eObject instanceof Node) {
+                        Node node = (Node) eObject;
+                        // Only enum literals and new nodes are visible across problem files.
+                        return ProblemUtil.isEnumLiteral(node) || ProblemUtil.isNewNode(node);
+                }
+                return true;
+        }
+        
         protected boolean shouldExportSimpleName(EObject eObject) {
                 if (eObject instanceof Node) {
                         return !ProblemUtil.isNewNode((Node) eObject);
diff --git a/language/src/main/java/org/eclipse/viatra/solver/language/scoping/ProblemScopeProvider.java b/language/src/main/java/org/eclipse/viatra/solver/language/scoping/ProblemScopeProvider.java
index 3748e81d..597085a8 100644
--- a/language/src/main/java/org/eclipse/viatra/solver/language/scoping/ProblemScopeProvider.java
+++ b/language/src/main/java/org/eclipse/viatra/solver/language/scoping/ProblemScopeProvider.java
@@ -13,6 +13,7 @@ import org.eclipse.viatra.solver.language.ProblemUtil;
 import org.eclipse.viatra.solver.language.model.problem.ClassDeclaration;
 import org.eclipse.viatra.solver.language.model.problem.ExistentialQuantifier;
 import org.eclipse.viatra.solver.language.model.problem.PredicateDefinition;
+import org.eclipse.viatra.solver.language.model.problem.Problem;
 import org.eclipse.viatra.solver.language.model.problem.ProblemPackage;
 import org.eclipse.viatra.solver.language.model.problem.ReferenceDeclaration;
 import org.eclipse.viatra.solver.language.model.problem.Relation;
@@ -34,14 +35,27 @@ public class ProblemScopeProvider extends AbstractProblemScopeProvider {
         @Override
         public IScope getScope(EObject context, EReference reference) {
                 IScope scope = super.getScope(context, reference);
+                if (reference == ProblemPackage.Literals.NODE_ASSERTION_ARGUMENT__NODE
+                                || reference == ProblemPackage.Literals.NODE_VALUE_ASSERTION__NODE) {
+                        return getNodesScope(context, scope);
+                }
                 if (reference == ProblemPackage.Literals.VARIABLE_OR_NODE_ARGUMENT__VARIABLE_OR_NODE) {
                         return getVariableScope(context, scope);
-                } else if (reference == ProblemPackage.Literals.REFERENCE_DECLARATION__OPPOSITE) {
+                }
+                if (reference == ProblemPackage.Literals.REFERENCE_DECLARATION__OPPOSITE) {
                         return getOppositeScope(context, scope);
                 }
                 return scope;
         }
 
+        protected IScope getNodesScope(EObject context, IScope delegateScope) {
+                Problem problem = EcoreUtil2.getContainerOfType(context, Problem.class);
+                if (problem == null) {
+                        return delegateScope;
+                }
+                return Scopes.scopeFor(problem.getNodes(), delegateScope);
+        }
+
         protected IScope getVariableScope(EObject context, IScope delegateScope) {
                 List<Variable> variables = new ArrayList<>();
                 EObject currentContext = context;
@@ -63,7 +77,7 @@ public class ProblemScopeProvider extends AbstractProblemScopeProvider {
                         PredicateDefinition definition = (PredicateDefinition) currentContext;
                         variables.addAll(definition.getParameters());
                 }
-                return Scopes.scopeFor(variables, delegateScope);
+                return Scopes.scopeFor(variables, getNodesScope(context, delegateScope));
         }
 
         protected IScope getOppositeScope(EObject context, IScope delegateScope) {