GROOVY-5106, GROOVY-11508: re-implement trait with new type args warning

(closes #2117)

Author: eric-milles

src/main/java/org/codehaus/groovy/classgen/Verifier.java

@@ -363,9 +363,15 @@ private static void checkForDuplicateInterfaces(final ClassNode cn) {
                             for (ClassNode t : set) { // find match and check generics
                                 if (t.equals(in)) {
                                     String one = in.toString(false), two = t.toString(false);
-                                    if (!one.equals(two))
-                                        throw new RuntimeParserException("The interface " + in.getNameWithoutPackage() +
-                                            " cannot be implemented more than once with different arguments: " + one + " and " + two, cn);
+                                    if (!one.equals(two)) {
+                                        if (Traits.isTrait(in)) { // GROOVY-11508
+                                            cn.getModule().getContext().addWarning("The trait " + in.getNameWithoutPackage() +
+                                                " is implemented more than once with different arguments: " + one + " and " + two, cn);
+                                        } else {
+                                            throw new RuntimeParserException("The interface " + in.getNameWithoutPackage() +
+                                                " cannot be implemented more than once with different arguments: " + one + " and " + two, cn);
+                                        }
+                                    }
                                     break;
                                 }
                             }

src/main/java/org/codehaus/groovy/control/ResolveVisitor.java

@@ -265,61 +265,74 @@ protected SourceUnit getSourceUnit() {
         return source;
     }
 
+    @Override
+    public void visitField(final FieldNode node) {
+        Map<GenericsTypeName, GenericsType> oldNames = genericParameterNames;
+        if (!canSeeTypeVars(node.getModifiers(), node.getDeclaringClass())) {
+            genericParameterNames = Collections.emptyMap();
+        }
+
+        if (!fieldTypesChecked.contains(node)) {
+            resolveOrFail(node.getType(), node);
+        }
+        super.visitField(node);
+
+        genericParameterNames = oldNames;
+    }
+
+    @Override
+    public void visitProperty(final PropertyNode node) {
+        Map<GenericsTypeName, GenericsType> oldNames = genericParameterNames;
+        if (!canSeeTypeVars(node.getModifiers(), node.getDeclaringClass())) {
+            genericParameterNames = Collections.emptyMap();
+        }
+
+        resolveOrFail(node.getType(), node);
+        fieldTypesChecked.add(node.getField());
+
+        super.visitProperty(node);
+
+        genericParameterNames = oldNames;
+    }
+
+    private static boolean canSeeTypeVars(final int mods, final ClassNode node) {
+        return !Modifier.isStatic(mods) || Traits.isTrait(node); // GROOVY-8864, GROOVY-11508
+    }
+
     @Override
     protected void visitConstructorOrMethod(final MethodNode node, final boolean isConstructor) {
         VariableScope oldScope = currentScope;
         currentScope = node.getVariableScope();
         Map<GenericsTypeName, GenericsType> oldNames = genericParameterNames;
-        genericParameterNames = node.isStatic() && !Traits.isTrait(node.getDeclaringClass())
-                ? new HashMap<>() : new HashMap<>(genericParameterNames);
+        genericParameterNames =
+                canSeeTypeVars(node.getModifiers(), node.getDeclaringClass())
+                    ? new HashMap<>(genericParameterNames) : new HashMap<>();
 
         resolveGenericsHeader(node.getGenericsTypes());
 
+        resolveOrFail(node.getReturnType(), node);
         for (Parameter p : node.getParameters()) {
             p.setInitialExpression(transform(p.getInitialExpression()));
-            resolveOrFail(p.getType(), p.getType());
+            ClassNode t = p.getType();
+            resolveOrFail(t, t);
             visitAnnotations(p);
         }
-        resolveOrFail(node.getReturnType(), node);
         if (node.getExceptions() != null) {
             for (ClassNode t : node.getExceptions()) {
-                resolveOrFail(t, node);
+                resolveOrFail(t, t);
             }
         }
 
         MethodNode oldCurrentMethod = currentMethod;
         currentMethod = node;
+
         super.visitConstructorOrMethod(node, isConstructor);
 
         currentMethod = oldCurrentMethod;
         genericParameterNames = oldNames;
         currentScope = oldScope;
     }
 
-    @Override
-    public void visitField(final FieldNode node) {
-        ClassNode t = node.getType();
-        if (!fieldTypesChecked.contains(node)) {
-            resolveOrFail(t, node);
-        }
-        super.visitField(node);
-    }
-
-    @Override
-    public void visitProperty(final PropertyNode node) {
-        Map<GenericsTypeName, GenericsType> oldPNames = genericParameterNames;
-        if (node.isStatic() && !Traits.isTrait(node.getDeclaringClass())) {
-            genericParameterNames = new HashMap<>();
-        }
-
-        ClassNode t = node.getType();
-        resolveOrFail(t, node);
-        super.visitProperty(node);
-        fieldTypesChecked.add(node.getField());
-
-        genericParameterNames = oldPNames;
-    }
-
     private void resolveOrFail(final ClassNode type, final ASTNode node) {
         resolveOrFail(type, "", node);
     }
@@ -1108,14 +1121,14 @@ protected Expression transformBinaryExpression(final BinaryExpression be) {
     protected Expression transformClosureExpression(final ClosureExpression ce) {
         boolean oldInClosure = inClosure;
         inClosure = true;
-        for (Parameter para : getParametersSafe(ce)) {
-            ClassNode t = para.getType();
-            resolveOrFail(t, ce);
-            visitAnnotations(para);
-            if (para.hasInitialExpression()) {
-                para.setInitialExpression(transform(para.getInitialExpression()));
+        for (Parameter p : getParametersSafe(ce)) {
+            ClassNode t = p.getType();
+            resolveOrFail(t, t);
+            visitAnnotations(p);
+            if (p.hasInitialExpression()) {
+                p.setInitialExpression(transform(p.getInitialExpression()));
             }
-            visitAnnotations(para);
+            visitAnnotations(p);
         }
 
         Statement code = ce.getCode();

src/test/org/codehaus/groovy/transform/traitx/Groovy11508.groovy

@@ -0,0 +1,45 @@
+/*
+ *  Licensed to the Apache Software Foundation (ASF) under one
+ *  or more contributor license agreements.  See the NOTICE file
+ *  distributed with this work for additional information
+ *  regarding copyright ownership.  The ASF licenses this file
+ *  to you under the Apache License, Version 2.0 (the
+ *  "License"); you may not use this file except in compliance
+ *  with the License.  You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *  Unless required by applicable law or agreed to in writing,
+ *  software distributed under the License is distributed on an
+ *  "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ *  KIND, either express or implied.  See the License for the
+ *  specific language governing permissions and limitations
+ *  under the License.
+ */
+package org.codehaus.groovy.transform.traitx
+
+import org.junit.Test
+
+import static groovy.test.GroovyAssert.assertScript
+
+final class Groovy11508 {
+    @Test
+    void testGenericsAppliedToStaticMethodsForTraits() {
+        assertScript '''
+            trait T<U> {
+                static U getYou() {
+                }
+            }
+            class C implements T<C> {
+            }
+            class D extends C implements T<D> {
+            }
+
+            C c = C.you
+            D d = D.you
+
+            assert C.getMethod('getYou').returnType == C
+            assert D.getMethod('getYou').returnType == D
+        '''
+    }
+}

src/test/groovy/bugs/Groovy8864Bug.groovy renamed to src/test/org/codehaus/groovy/transform/traitx/Groovy8864.groovy

@@ -16,24 +16,27 @@
  *  specific language governing permissions and limitations
  *  under the License.
  */
-package groovy.bugs
+package org.codehaus.groovy.transform.traitx
 
-import groovy.test.GroovyTestCase
+import org.junit.Test
 
-class Groovy8864Bug extends GroovyTestCase {
+import static groovy.test.GroovyAssert.assertScript
+
+final class Groovy8864 {
+    @Test
     void testGenericsAppliedToStaticMethodsForTraits() {
         assertScript '''
             trait Foo<T> {
                 static T INSTANCE
-                static T get(T arg) { 
-                    null
-               }
+                static T get(T t) {
+                }
+            }
+            class Bar implements Foo<Bar> {
             }
 
-            class Bar implements Foo<Bar> {}
             assert Bar.getMethod("get", [Bar] as Class[]).returnType == Bar
             assert Bar.getDeclaredField("Foo__INSTANCE").type == Bar
-            assert Bar.getMethod("setINSTANCE", [Bar] as Class[])
+            assert Bar.getMethod("setINSTANCE", new Class[]{Bar})
             assert Bar.getMethod("getINSTANCE").returnType == Bar
         '''
     }