method signature: don't substitute twice during erasure (IDEA-167386)

java/java-psi-api/src/com/intellij/psi/util/MethodSignatureUtil.java

@@ -88,7 +88,7 @@ public class MethodSignatureUtil {
     PsiSubstitutor substitutor = signature.getSubstitutor();
     PsiType[] erasedTypes = PsiType.createArray(parameterTypes.length);
     for (int i = 0; i < parameterTypes.length; i++) {
-      erasedTypes[i] = TypeConversionUtil.erasure(substitutor.substitute(parameterTypes[i]), substitutor);
+      erasedTypes[i] = TypeConversionUtil.erasure(parameterTypes[i], substitutor);
     }
     return erasedTypes;
   }

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/genericsHighlighting/AvoidDblSubstitutionDuringErasureOfParameterTypesOfMethodSignature.java

@@ -0,0 +1,10 @@
+class Foo<T> {
+  void run(T param) {}
+
+  void anonymousClass() {
+    new Foo<T[]>() {
+      @Override
+      void run(T[] param) {}
+    };
+  }
+}

java/java-tests/testSrc/com/intellij/codeInsight/daemon/GenericsHighlightingTest.java

@@ -622,4 +622,8 @@ public class GenericsHighlightingTest extends LightDaemonAnalyzerTestCase {
   public void testNotErasedReturnValueUnderJdk7() throws Exception {
     doTest(LanguageLevel.JDK_1_7, JavaSdkVersion.JDK_1_8, false);
   }
+
+  public void testAvoidDblSubstitutionDuringErasureOfParameterTypesOfMethodSignature() throws Exception {
+    doTest(LanguageLevel.JDK_1_7, JavaSdkVersion.JDK_1_8, false);
+  }
 }