From bf9c220dfceef52195ec7ebf0fd633b50994d56a Mon Sep 17 00:00:00 2001
From: Tagir Valeev <tagir.valeev@jetbrains.com>
Date: Mon, 21 Oct 2024 15:33:27 +0200
Subject: [PATCH] [java-inspections] Uncomment old 'toList() can be used'
 tests; fix false-positives

Some false-negatives still exist but they are rare cases, so let's skip them for now

GitOrigin-RevId: 7c3af14c332768267123320f1601dd1fd76ff240
---
 ...atchedCollectionQueryUpdateInspection.java |   2 +
 .../CollectCollectorsToList.java              | 117 +++++++++---------
 2 files changed, 60 insertions(+), 59 deletions(-)

diff --git a/java/java-impl/src/com/siyeh/ig/bugs/MismatchedCollectionQueryUpdateInspection.java b/java/java-impl/src/com/siyeh/ig/bugs/MismatchedCollectionQueryUpdateInspection.java
index 3b7d26ae0150..7ab294a0a61f 100644
--- a/java/java-impl/src/com/siyeh/ig/bugs/MismatchedCollectionQueryUpdateInspection.java
+++ b/java/java-impl/src/com/siyeh/ig/bugs/MismatchedCollectionQueryUpdateInspection.java
@@ -659,6 +659,8 @@ public final class MismatchedCollectionQueryUpdateInspection extends BaseInspect
     PsiElement parent = effectiveReference.getParent();
     Set<PsiReferenceExpression> ignored = new HashSet<>();
     if (parent instanceof PsiAssignmentExpression assignmentExpression) {
+      // Do not process when the result of assignment is used: rare case
+      if (!ExpressionUtils.isVoidContext(assignmentExpression)) return false;
       if(assignmentExpression.getLExpression() instanceof PsiReferenceExpression referenceExpression){
         ignored.add(referenceExpression);
         parent = referenceExpression.resolve();
diff --git a/java/java-tests/testData/inspection/simplifyStreamApiCallChains/CollectCollectorsToList.java b/java/java-tests/testData/inspection/simplifyStreamApiCallChains/CollectCollectorsToList.java
index e3b6aa9082fa..261131bc6a4b 100644
--- a/java/java-tests/testData/inspection/simplifyStreamApiCallChains/CollectCollectorsToList.java
+++ b/java/java-tests/testData/inspection/simplifyStreamApiCallChains/CollectCollectorsToList.java
@@ -185,64 +185,63 @@ class MissingIteratorRemoveAnalysis {
       System.out.println(string);
     }
   }
-}
 
-//class TODO() {
-//
-//    void testMustHave1(Stream<String> stream) {
-//        List<String> list1;
-//        list1 = stream.collect(Collectors.toList());
-//        list1.forEach(System.out::println);
-//    }
-//
-//    void testMustHave2(Stream<String> stream) {
-//        List<String> list1;
-//        list1 = stream.collect(Collectors.toList());
-//        list1.add("foo");
-//    }
-//
-//    void test1(Stream<String> stream) {
-//        List<String> list1;
-//        List<String> list2;
-//        list1 = ((list2 = ((stream.collect(Collectors.toList())))));
-//        list1.forEach(System.out::println);
-//        list2.forEach(System.out::println);
-//    }
-//
-//    void test2(Stream<String> stream) {
-//        List<String> list1;
-//        List<String> list2;
-//        list1 = ((list2 = ((stream.collect(Collectors.toList())))));
-//        list1.add("foo");
-//    }
-//
-//    void test3(Stream<String> stream) {
-//        List<String> list1;
-//        List<String> list2;
-//        list1 = ((list2 = ((stream.collect(Collectors.toList())))));
-//        list2.add("foo");
-//    }
-//
-//    void test4(Stream<String> stream) {
-//        List<String> list1;
-//        list1 = stream.collect(Collectors.toList());
-//        list1.add("foo");
-//    }
-//
-//    void test5(Stream<String> stream) {
-//        List<String> subList = stream.collect(Collectors.toList()).subList(0, 3);
-//        subList.add("foo");
-//    }
-//
-//    void test6(Stream<String> stream) {
-//        List<String> subList = stream.collect(Collectors.toList()).subList(0, 3);
-//        subList.forEach(System.out::println);
-//    }
+    void testMustHave1(Stream<String> stream) {
+        List<String> list1;
+        list1 = stream.<warning descr="'collect(toList())' can be replaced with 'toList()'">collect(Collectors.toList())</warning>;
+        list1.forEach(System.out::println);
+    }
 
-//    void test7(Stream<String> stream) {
-//        List<String> list = stream.collect(Collectors.toList());
-//        list.forEach(System.out::println);
-//        list = new ArrayList<>();
-//        list.add("foo");
-//    }
-//}
\ No newline at end of file
+    void testMustHave2(Stream<String> stream) {
+        List<String> list1;
+        list1 = stream.collect(Collectors.toList());
+        list1.add("foo");
+    }
+
+    void test1(Stream<String> stream) {
+        List<String> list1;
+        List<String> list2;
+        // Theoretically could be supported but for now we ignore cases when assignment result is used
+        list1 = ((list2 = ((stream.collect(Collectors.toList())))));
+        list1.forEach(System.out::println);
+        list2.forEach(System.out::println);
+    }
+
+    void test2(Stream<String> stream) {
+        List<String> w1;
+        List<String> w2;
+        w1 = ((w2 = ((stream.collect(Collectors.toList())))));
+        w1.add("foo");
+    }
+
+    void test3(Stream<String> stream) {
+        List<String> w1;
+        List<String> w2;
+        w1 = ((w2 = ((stream.collect(Collectors.toList())))));
+        w2.add("foo");
+    }
+
+    void test4(Stream<String> stream) {
+        List<String> list1;
+        list1 = stream.collect(Collectors.toList());
+        list1.add("foo");
+    }
+
+    void test5(Stream<String> stream) {
+        List<String> subList = stream.collect(Collectors.toList()).subList(0, 3);
+        subList.add("foo");
+    }
+
+    void test6(Stream<String> stream) {
+        List<String> subList = stream.<warning descr="'collect(toList())' can be replaced with 'toList()'">collect(Collectors.toList())</warning>.subList(0, 3);
+        subList.forEach(System.out::println);
+    }
+
+    // TODO
+    void test7(Stream<String> stream) {
+        List<String> list = stream.collect(Collectors.toList());
+        list.forEach(System.out::println);
+        list = new ArrayList<>();
+        list.add("foo");
+    }
+}
\ No newline at end of file