From 5f609b11bce2eaa0db0090e8ce9e62a797938800 Mon Sep 17 00:00:00 2001
From: Max Medvedev <maxim.medvedev@jetbrains.com>
Date: Tue, 30 Apr 2013 12:32:04 +0400
Subject: [PATCH] IDEA-106374 Overriding method can change return type generics

---
 .../groovy/annotator/GroovyAnnotator.java     | 58 +++++++++------
 .../GroovyHighlightingTest.groovy             | 71 +++++++++++++++++++
 2 files changed, 108 insertions(+), 21 deletions(-)

diff --git a/plugins/groovy/src/org/jetbrains/plugins/groovy/annotator/GroovyAnnotator.java b/plugins/groovy/src/org/jetbrains/plugins/groovy/annotator/GroovyAnnotator.java
index 7cb03049ed19..4f71412c9309 100644
--- a/plugins/groovy/src/org/jetbrains/plugins/groovy/annotator/GroovyAnnotator.java
+++ b/plugins/groovy/src/org/jetbrains/plugins/groovy/annotator/GroovyAnnotator.java
@@ -895,13 +895,42 @@ public class GroovyAnnotator extends GroovyElementVisitor {
   }
 
   @Nullable
-  private static String checkSuperMethodSignature(PsiMethod superMethod,
-                                                  MethodSignatureBackedByPsiMethod superMethodSignature,
-                                                  PsiType superReturnType,
-                                                  PsiMethod method,
-                                                  MethodSignatureBackedByPsiMethod methodSignature,
-                                                  PsiType returnType) {
-    if (superReturnType == null) return null;
+  private static String checkSuperMethodSignature(@NotNull PsiMethod superMethod,
+                                                  @NotNull MethodSignatureBackedByPsiMethod superMethodSignature,
+                                                  @NotNull PsiType superReturnType,
+                                                  @NotNull PsiMethod method,
+                                                  @NotNull MethodSignatureBackedByPsiMethod methodSignature,
+                                                  @NotNull PsiType returnType) {
+    PsiType substitutedSuperReturnType = substituteSuperReturnType(superMethodSignature, methodSignature, superReturnType);
+
+    if (returnType.equals(substitutedSuperReturnType)) return null;
+
+    final PsiType rawReturnType = TypeConversionUtil.erasure(returnType);
+    final PsiType rawSuperReturnType = TypeConversionUtil.erasure(substitutedSuperReturnType);
+
+    if (returnType instanceof PsiClassType && substitutedSuperReturnType instanceof PsiClassType) {
+      if (TypeConversionUtil.isAssignable(rawSuperReturnType, rawReturnType)) {
+        return null;
+      }
+    }
+    else if (returnType instanceof PsiArrayType && superReturnType instanceof PsiArrayType) {
+      if (rawReturnType.equals(rawSuperReturnType)) {
+        return null;
+      }
+    }
+
+    String qName = getQNameOfMember(method);
+    String baseQName = getQNameOfMember(superMethod);
+    final String presentation = returnType.getCanonicalText() + " " + GroovyPresentationUtil.getSignaturePresentation(methodSignature);
+    final String basePresentation =
+      superReturnType.getCanonicalText() + " " + GroovyPresentationUtil.getSignaturePresentation(superMethodSignature);
+    return GroovyBundle.message("return.type.is.incompatible", presentation, qName, basePresentation, baseQName);
+  }
+
+  @NotNull
+  private static PsiType substituteSuperReturnType(@NotNull MethodSignatureBackedByPsiMethod superMethodSignature,
+                                                   @NotNull MethodSignatureBackedByPsiMethod methodSignature,
+                                                   @NotNull PsiType superReturnType) {
     PsiType substitutedSuperReturnType;
     if (!superMethodSignature.isRaw() && superMethodSignature.equals(methodSignature)) { //see 8.4.5
       PsiSubstitutor unifyingSubstitutor = MethodSignatureUtil.getSuperMethodSignatureSubstitutor(methodSignature,
@@ -913,20 +942,7 @@ public class GroovyAnnotator extends GroovyElementVisitor {
     else {
       substitutedSuperReturnType = TypeConversionUtil.erasure(superReturnType);
     }
-
-    if (returnType.equals(substitutedSuperReturnType)) return null;
-    if (!(returnType instanceof PsiPrimitiveType) &&
-        substitutedSuperReturnType.getDeepComponentType() instanceof PsiClassType &&
-        TypeConversionUtil.isAssignable(substitutedSuperReturnType, returnType)) {
-      return null;
-    }
-
-    String qName = getQNameOfMember(method);
-    String baseQName = getQNameOfMember(superMethod);
-    final String presentation = returnType.getCanonicalText() + " " + GroovyPresentationUtil.getSignaturePresentation(methodSignature);
-    final String basePresentation =
-      superReturnType.getCanonicalText() + " " + GroovyPresentationUtil.getSignaturePresentation(superMethodSignature);
-    return GroovyBundle.message("return.type.is.incompatible", presentation, qName, basePresentation, baseQName);
+    return substitutedSuperReturnType;
   }
 
   @NotNull
diff --git a/plugins/groovy/test/org/jetbrains/plugins/groovy/lang/highlighting/GroovyHighlightingTest.groovy b/plugins/groovy/test/org/jetbrains/plugins/groovy/lang/highlighting/GroovyHighlightingTest.groovy
index dcdf59c935ea..70a3b260972d 100644
--- a/plugins/groovy/test/org/jetbrains/plugins/groovy/lang/highlighting/GroovyHighlightingTest.groovy
+++ b/plugins/groovy/test/org/jetbrains/plugins/groovy/lang/highlighting/GroovyHighlightingTest.groovy
@@ -1262,4 +1262,75 @@ class D<T, E> {
   def foo(E t) {}
 }''')
   }
+
+  void testOverriddenReturnType0() {
+    myFixture.addClass('class Base{}')
+    myFixture.addClass('class Inh extends Base{}')
+    testHighlighting('''\
+class A {
+  List<Base> foo() {}
+}
+
+class B extends A {
+  List<Inh> foo() {} //correct
+}
+''')
+  }
+
+  void testOverriddenReturnType1() {
+    myFixture.addClass('class Base extends SuperBase {}')
+    myFixture.addClass('class Inh extends Base{}')
+    testHighlighting('''\
+class A {
+  List<Base> foo() {}
+}
+
+class B extends A {
+  <error>Collection<Base></error> foo() {}
+}
+''')
+  }
+
+  void testOverriddenReturnType2() {
+    myFixture.addClass('class Base extends SuperBase {}')
+    myFixture.addClass('class Inh extends Base{}')
+    testHighlighting('''\
+class A {
+  List<Base> foo() {}
+}
+
+class B extends A {
+  <error>int</error> foo() {}
+}
+''')
+  }
+
+  void testOverriddenReturnType3() {
+    myFixture.addClass('class Base extends SuperBase {}')
+    myFixture.addClass('class Inh extends Base{}')
+    testHighlighting('''\
+class A {
+  Base[] foo() {}
+}
+
+class B extends A {
+  <error>Inh[]</error> foo() {}
+}
+''')
+  }
+
+  void testOverriddenReturnType4() {
+    myFixture.addClass('class Base extends SuperBase {}')
+    myFixture.addClass('class Inh extends Base{}')
+    testHighlighting('''\
+class A {
+  Base[] foo() {}
+}
+
+class B extends A {
+  Base[] foo() {}
+}
+''')
+  }
+
 }
\ No newline at end of file