java completion: don't insert method type arguments if they weren't inferred (IDEA-198368)

java/java-impl/src/com/intellij/codeInsight/completion/JavaMethodCallElement.java

@@ -457,7 +457,8 @@ public class JavaMethodCallElement extends LookupItem<PsiMethod> implements Type
 
     List<PsiType> substituted = ContainerUtil.map(parameters, parameter -> {
       PsiType type = substitutor.substitute(parameter);
-      return type instanceof PsiWildcardType ? ((PsiWildcardType)type).getExtendsBound() : type;
+      if (type instanceof PsiWildcardType) type = ((PsiWildcardType)type).getExtendsBound();
+      return PsiUtil.resolveClassInClassTypeOnly(type) == parameter ? null : type;
     });
     if (ContainerUtil.exists(substituted, t -> t == null || t instanceof PsiCapturedWildcardType)) return null;
     if (substituted.equals(ContainerUtil.map(parameters, TypeConversionUtil::typeParameterErasure))) return null;

java/java-tests/testData/codeInsight/completion/normal/GenericInsideDiamond.java

@@ -0,0 +1,18 @@
+import java.util.Comparator;
+
+class T {
+
+  {
+    new TreeSet<>(Ordering.na<caret>)
+  }
+}
+
+abstract class Ordering<T> implements Comparator<T> {
+  static <C extends Comparable> Ordering<C> natural() {
+  }
+}
+
+class TreeSet<E> {
+  TreeSet(Comparator<? super E> c) {
+  }
+}

java/java-tests/testData/codeInsight/completion/normal/GenericInsideDiamond_after.java

@@ -0,0 +1,18 @@
+import java.util.Comparator;
+
+class T {
+
+  {
+    new TreeSet<>(Ordering.natural()<caret>)
+  }
+}
+
+abstract class Ordering<T> implements Comparator<T> {
+  static <C extends Comparable> Ordering<C> natural() {
+  }
+}
+
+class TreeSet<E> {
+  TreeSet(Comparator<? super E> c) {
+  }
+}

java/java-tests/testSrc/com/intellij/java/codeInsight/completion/Normal7CompletionTest.groovy

@@ -0,0 +1,16 @@
+// Copyright 2000-2019 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
+package com.intellij.java.codeInsight.completion
+
+import com.intellij.testFramework.LightProjectDescriptor
+import groovy.transform.CompileStatic
+/**
+ * @author peter
+ */
+@CompileStatic
+class Normal7CompletionTest extends NormalCompletionTestCase {
+  final LightProjectDescriptor projectDescriptor = JAVA_1_7
+
+  void testGenericInsideDiamond() { doTest() }
+
+
+}