refactor(language): scope shadowing

3 files changed, 58 insertions, 7 deletions

diff --git a/subprojects/language/src/main/java/tools/refinery/language/scoping/ProblemGlobalScopeProvider.java b/subprojects/language/src/main/java/tools/refinery/language/scoping/ProblemGlobalScopeProvider.java
index dad4e5d0..65e80a7e 100644
--- a/subprojects/language/src/main/java/tools/refinery/language/scoping/ProblemGlobalScopeProvider.java
+++ b/subprojects/language/src/main/java/tools/refinery/language/scoping/ProblemGlobalScopeProvider.java
@@ -15,10 +15,9 @@ import org.eclipse.xtext.resource.IEObjectDescription;
 import org.eclipse.xtext.resource.ISelectable;
 import org.eclipse.xtext.scoping.IScope;
 import org.eclipse.xtext.scoping.impl.AbstractGlobalScopeProvider;
-import org.eclipse.xtext.scoping.impl.SelectableBasedScope;
 import org.eclipse.xtext.util.IResourceScopeCache;
-import tools.refinery.language.scoping.imports.ImportCollector;
 import tools.refinery.language.resource.LoadOnDemandResourceDescriptionProvider;
+import tools.refinery.language.scoping.imports.ImportCollector;
 import tools.refinery.language.scoping.imports.NamedImport;
 
 import java.util.ArrayList;
@@ -81,7 +80,7 @@ public class ProblemGlobalScopeProvider extends AbstractGlobalScopeProvider {
         protected IScope createScope(IScope parent, Collection<? extends ISelectable> children, EClass type,
                                                                  Predicate<IEObjectDescription> filter, boolean ignoreCase) {
                 var selectable = CompositeSelectable.of(children);
-                return SelectableBasedScope.createScope(parent, selectable, filter, type, ignoreCase);
+                return ShadowingKeyAwareSelectableBasedScope.createScope(parent, selectable, filter, type, ignoreCase);
         }
 
         protected record LoadedImports(List<ISelectable> qualifiedImports, List<ISelectable> implicitImports,
diff --git a/subprojects/language/src/main/java/tools/refinery/language/scoping/ProblemLocalScopeProvider.java b/subprojects/language/src/main/java/tools/refinery/language/scoping/ProblemLocalScopeProvider.java
index 610efc03..1c0c1d86 100644
--- a/subprojects/language/src/main/java/tools/refinery/language/scoping/ProblemLocalScopeProvider.java
+++ b/subprojects/language/src/main/java/tools/refinery/language/scoping/ProblemLocalScopeProvider.java
@@ -17,7 +17,6 @@ import org.eclipse.xtext.resource.IResourceDescriptionsProvider;
 import org.eclipse.xtext.resource.ISelectable;
 import org.eclipse.xtext.scoping.IScope;
 import org.eclipse.xtext.scoping.impl.AbstractGlobalScopeDelegatingScopeProvider;
-import org.eclipse.xtext.scoping.impl.SelectableBasedScope;
 import org.eclipse.xtext.util.IResourceScopeCache;
 import tools.refinery.language.naming.ProblemQualifiedNameProvider;
 
@@ -47,12 +46,13 @@ public class ProblemLocalScopeProvider extends AbstractGlobalScopeDelegatingScop
                 var globalScope = getGlobalScope(resource, reference);
                 var type = reference.getEReferenceType();
                 boolean ignoreCase = isIgnoreCase(reference);
-                var scope = SelectableBasedScope.createScope(globalScope, localImports.resourceDescription(), type,
-                ignoreCase);
+                var scope = ShadowingKeyAwareSelectableBasedScope.createScope(globalScope, localImports.resourceDescription(),
+                                type, ignoreCase);
                 if (localImports.normalizedSelectable() == null) {
                         return scope;
                 }
-                return SelectableBasedScope.createScope(scope, localImports.normalizedSelectable(), type, ignoreCase);
+                return ShadowingKeyAwareSelectableBasedScope.createScope(scope, localImports.normalizedSelectable(), type,
+                                ignoreCase);
         }
 
         protected LocalImports computeLocalImports(Resource resource) {
diff --git a/subprojects/language/src/main/java/tools/refinery/language/scoping/ShadowingKeyAwareSelectableBasedScope.java b/subprojects/language/src/main/java/tools/refinery/language/scoping/ShadowingKeyAwareSelectableBasedScope.java
new file mode 100644
index 00000000..cdef13ad
--- /dev/null
+++ b/subprojects/language/src/main/java/tools/refinery/language/scoping/ShadowingKeyAwareSelectableBasedScope.java
@@ -0,0 +1,52 @@
+/*
+ * SPDX-FileCopyrightText: 2024 The Refinery Authors <https://refinery.tools/>
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ */
+package tools.refinery.language.scoping;
+
+import com.google.common.base.Predicate;
+import org.eclipse.emf.ecore.EClass;
+import org.eclipse.xtext.resource.IEObjectDescription;
+import org.eclipse.xtext.resource.ISelectable;
+import org.eclipse.xtext.scoping.IScope;
+import org.eclipse.xtext.scoping.impl.SelectableBasedScope;
+import tools.refinery.language.resource.ProblemResourceDescriptionStrategy;
+
+import java.util.Objects;
+
+public class ShadowingKeyAwareSelectableBasedScope extends SelectableBasedScope {
+        public static IScope createScope(IScope outer, ISelectable selectable, EClass type, boolean ignoreCase) {
+                return createScope(outer, selectable, null, type, ignoreCase);
+        }
+
+        // {@link com.google.common.base.Predicate} required by Xtext API.
+        @SuppressWarnings("squid:S4738")
+        public static IScope createScope(IScope outer, ISelectable selectable, Predicate<IEObjectDescription> filter,
+                                                                         EClass type, boolean ignoreCase) {
+                if (selectable == null || selectable.isEmpty())
+                        return outer;
+                return new ShadowingKeyAwareSelectableBasedScope(outer, selectable, filter, type, ignoreCase);
+        }
+
+        // {@link com.google.common.base.Predicate} required by Xtext API.
+        @SuppressWarnings("squid:S4738")
+        protected ShadowingKeyAwareSelectableBasedScope(IScope outer, ISelectable selectable,
+                                                                                                        Predicate<IEObjectDescription> filter,
+                                                                                                        EClass type, boolean ignoreCase) {
+                super(outer, selectable, filter, type, ignoreCase);
+        }
+
+        @Override
+        protected boolean isShadowed(IEObjectDescription input) {
+                var shadowingKey = input.getUserData(ProblemResourceDescriptionStrategy.SHADOWING_KEY);
+                var localElements = getLocalElementsByName(input.getName());
+                for (var localElement : localElements) {
+                        var localElementKey = localElement.getUserData(ProblemResourceDescriptionStrategy.SHADOWING_KEY);
+                        if (Objects.equals(shadowingKey, localElementKey)) {
+                                return true;
+                        }
+                }
+                return false;
+        }
+}