StreamToLoop: fixed method references unwrap when functional interface type parameter is captured wildcard with upper bound

java/java-impl/src/com/intellij/codeInspection/streamToLoop/FunctionHelper.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2000-2016 JetBrains s.r.o.
+ * Copyright 2000-2017 JetBrains s.r.o.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -143,6 +143,7 @@ abstract class FunctionHelper {
     PsiType returnType = interfaceMethod.getReturnType();
     if (returnType == null) return null;
     returnType = ((PsiClassType)type).resolveGenerics().getSubstitutor().substitute(returnType);
+    type = fixType(type, expression.getProject());
     if (expression instanceof PsiLambdaExpression) {
       PsiLambdaExpression lambda = (PsiLambdaExpression)expression;
       PsiParameterList list = lambda.getParameterList();
@@ -180,6 +181,29 @@ abstract class FunctionHelper {
     return new ComplexExpressionFunctionHelper(returnType, type, interfaceMethod.getName(), expression);
   }
 
+  private static PsiType fixType(PsiType type, Project project) {
+    if(type instanceof PsiClassType) {
+      PsiClassType classType = (PsiClassType)type;
+      PsiClass aClass = classType.resolve();
+      if (aClass != null && classType.getParameterCount() != 0) {
+        PsiType[] parameters = classType.getParameters();
+        Arrays.asList(parameters).replaceAll(t -> fixType(t, project));
+        return JavaPsiFacade.getElementFactory(project).createType(aClass, parameters);
+      }
+    }
+    else if(type instanceof PsiArrayType) {
+      PsiType componentType = ((PsiArrayType)type).getComponentType();
+      PsiType fixedType = fixType(componentType, project);
+      if(fixedType != componentType) {
+        return fixedType.createArrayType();
+      }
+    }
+    else if(type instanceof PsiCapturedWildcardType) {
+      return ((PsiCapturedWildcardType)type).getUpperBound();
+    }
+    return type;
+  }
+
   @Nullable
   private static String tryInlineMethodReference(int paramCount, PsiMethodReferenceExpression methodRef) {
     PsiElement element = methodRef.resolve();

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/quickFix/streamToLoop/afterCapturedWildcard.java

@@ -0,0 +1,26 @@
+// "Replace Stream API chain with loop" "true"
+
+import java.util.List;
+import java.util.OptionalInt;
+
+public class Main {
+  interface Index {
+    int asInteger();
+  }
+  interface IndexSet<S extends Index> {
+    List<S> asList();
+  }
+
+  public static OptionalInt min(IndexSet<?> set) {
+      boolean seen = false;
+      int best = 0;
+      for (Index index : set.asList()) {
+          int i = index.asInteger();
+          if (!seen || i < best) {
+              seen = true;
+              best = i;
+          }
+      }
+      return seen ? OptionalInt.of(best) : OptionalInt.empty();
+  }
+}

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/quickFix/streamToLoop/beforeCapturedWildcard.java

@@ -0,0 +1,20 @@
+// "Replace Stream API chain with loop" "true"
+
+import java.util.List;
+import java.util.OptionalInt;
+
+public class Main {
+  interface Index {
+    int asInteger();
+  }
+  interface IndexSet<S extends Index> {
+    List<S> asList();
+  }
+
+  public static OptionalInt min(IndexSet<?> set) {
+    return set.asList()
+      .<caret>stream()
+      .mapToInt(Index::asInteger)
+      .min();
+  }
+}