From 1ab76a3b95f86f0d764905581d5542c670f1d537 Mon Sep 17 00:00:00 2001
From: Peter Gromov <peter@jetbrains.com>
Date: Wed, 17 Jun 2020 18:10:17 +0200
Subject: [PATCH] Skip some invalid/meaningless `.stream().*` completion
 suggestions (IDEA-243790)

GitOrigin-RevId: e02ac9f63fd6384ffe3f27f5c4825ddc3a5af58e
---
 .../codeInsight/completion/StreamConversion.java  | 15 ++++++++++-----
 .../normal/SuggestOnlyAccessibleStreamMethod.java |  9 +++++++++
 .../completion/Normal8CompletionTest.groovy       |  2 ++
 3 files changed, 21 insertions(+), 5 deletions(-)
 create mode 100644 java/java-tests/testData/codeInsight/daemonCodeAnalyzer/lambda/completion/normal/SuggestOnlyAccessibleStreamMethod.java

diff --git a/java/java-impl/src/com/intellij/codeInsight/completion/StreamConversion.java b/java/java-impl/src/com/intellij/codeInsight/completion/StreamConversion.java
index d29be4a325b7..10ff837eeca8 100644
--- a/java/java-impl/src/com/intellij/codeInsight/completion/StreamConversion.java
+++ b/java/java-impl/src/com/intellij/codeInsight/completion/StreamConversion.java
@@ -37,12 +37,17 @@ class StreamConversion {
     PsiType type = qualifier.getType();
     if (type instanceof PsiClassType) {
       PsiClass qualifierClass = ((PsiClassType)type).resolve();
-      if (qualifierClass == null) return Collections.emptyList();
+      if (qualifierClass == null || InheritanceUtil.isInheritor(qualifierClass, JAVA_UTIL_STREAM_BASE_STREAM)) {
+        return Collections.emptyList();
+      }
 
-      PsiMethod streamMethod = ContainerUtil.find(qualifierClass.findMethodsByName("stream", true), m ->
-        !m.hasParameters() &&
-        InheritanceUtil.isInheritor(m.getReturnType(), JAVA_UTIL_STREAM_BASE_STREAM));
-      if (streamMethod == null) return Collections.emptyList();
+      PsiMethod streamMethod = ContainerUtil.find(qualifierClass.findMethodsByName("stream", true), m -> !m.hasParameters());
+      if (streamMethod == null ||
+          streamMethod.hasModifierProperty(PsiModifier.STATIC) ||
+          !PsiUtil.isAccessible(streamMethod, ref, null) ||
+          !InheritanceUtil.isInheritor(streamMethod.getReturnType(), JAVA_UTIL_STREAM_BASE_STREAM)) {
+        return Collections.emptyList();
+      }
 
       return generateStreamSuggestions(parameters, qualifier, qualifier.getText() + ".stream()", context -> {
         String space = getSpace(CodeStyle.getLanguageSettings(context.getFile()).SPACE_WITHIN_EMPTY_METHOD_CALL_PARENTHESES);
diff --git a/java/java-tests/testData/codeInsight/daemonCodeAnalyzer/lambda/completion/normal/SuggestOnlyAccessibleStreamMethod.java b/java/java-tests/testData/codeInsight/daemonCodeAnalyzer/lambda/completion/normal/SuggestOnlyAccessibleStreamMethod.java
new file mode 100644
index 000000000000..9feedc61f6e5
--- /dev/null
+++ b/java/java-tests/testData/codeInsight/daemonCodeAnalyzer/lambda/completion/normal/SuggestOnlyAccessibleStreamMethod.java
@@ -0,0 +1,9 @@
+class Foo {
+  void foo(MyStream<String> list) {
+    list.ma<caret>
+  }
+}
+
+class MyStream<T> {
+  private java.util.stream.Stream<T> stream() {}
+}
\ No newline at end of file
diff --git a/java/java-tests/testSrc/com/intellij/java/codeInsight/completion/Normal8CompletionTest.groovy b/java/java-tests/testSrc/com/intellij/java/codeInsight/completion/Normal8CompletionTest.groovy
index 07d9281f2fae..7b02958efe4a 100644
--- a/java/java-tests/testSrc/com/intellij/java/codeInsight/completion/Normal8CompletionTest.groovy
+++ b/java/java-tests/testSrc/com/intellij/java/codeInsight/completion/Normal8CompletionTest.groovy
@@ -458,6 +458,8 @@ class Test88 {
     checkResultByFileName()
   }
 
+  void testSuggestOnlyAccessibleStreamMethod() { doAntiTest() }
+
   @NeedsIndex.ForStandardLibrary
   void testStreamMethodsOnArray() {
     configureByTestName()