IDEA-156379 Suggested "collect(Collectors.toList())" ignores static Collectors import

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

@@ -78,14 +78,14 @@ class CollectConversion {
     }
 
     if (listType != null) {
-      consumer.consume(new MyLookupElement("toList", listType));
+      consumer.consume(new MyLookupElement("toList", listType, ref));
     }
     if (setType != null) {
-      consumer.consume(new MyLookupElement("toSet", setType));
+      consumer.consume(new MyLookupElement("toSet", setType, ref));
     }
 
     if (expectedTypes.isEmpty() || hasIterable) {
-      consumer.consume(new MyLookupElement("toCollection", factory.createType(collection, component)));
+      consumer.consume(new MyLookupElement("toCollection", factory.createType(collection, component), ref));
     }
   }
 
@@ -94,12 +94,22 @@ class CollectConversion {
     private final String myTypeText;
     private final String myMethodName;
     @NotNull private final PsiType myExpectedType;
+    private final boolean myHasImport;
 
-    MyLookupElement(String methodName, @NotNull PsiType expectedType) {
+    MyLookupElement(String methodName, @NotNull PsiType expectedType, @NotNull PsiElement context) {
       myMethodName = methodName;
       myExpectedType = expectedType;
-      myLookupString = "collect(Collectors." + myMethodName + "())";
       myTypeText = myExpectedType.getPresentableText();
+
+      PsiMethodCallExpression call = (PsiMethodCallExpression)
+        JavaPsiFacade.getElementFactory(context.getProject()).createExpressionFromText(methodName + "()", context);
+      myHasImport = ContainerUtil.or(call.getMethodExpression().multiResolve(true), result -> {
+        PsiElement element = result.getElement();
+        return element instanceof PsiMember &&
+               (JAVA_UTIL_STREAM_COLLECTORS + "." + myMethodName).equals(PsiUtil.getMemberQualifiedName((PsiMember)element));
+      });
+
+      myLookupString = "collect(" + (myHasImport ? "" : "Collectors.") + myMethodName + "())";
     }
 
     @NotNull
@@ -143,7 +153,7 @@ class CollectConversion {
 
     @NotNull
     private String getInsertString() {
-      return "collect(" + JAVA_UTIL_STREAM_COLLECTORS + "." + myMethodName + "())";
+      return "collect(" + (myHasImport ? "" : JAVA_UTIL_STREAM_COLLECTORS + ".") + myMethodName + "())";
     }
 
     @Override

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/lambda/completion/normal/StaticallyImportedCollectorsToList.java

@@ -0,0 +1,8 @@
+import java.util.*;
+import static java.util.stream.Collectors.*;
+
+class Foo {
+  void m() {
+    List<CharSequence> l = Arrays.asList("a", "b").stream().colle<caret>
+  }
+}

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/lambda/completion/normal/StaticallyImportedCollectorsToList_after.java

@@ -0,0 +1,8 @@
+import java.util.*;
+import static java.util.stream.Collectors.*;
+
+class Foo {
+  void m() {
+    List<CharSequence> l = Arrays.asList("a", "b").stream().collect(toList());<caret>
+  }
+}

java/java-tests/testSrc/com/intellij/codeInsight/completion/Normal8CompletionTest.groovy

@@ -222,6 +222,12 @@ class Test88 {
     checkResultByFile(getTestName(false) + "_after.java")
   }
 
+  public void testStaticallyImportedCollectorsToList() {
+    configureByTestName()
+    selectItem(myItems.find { it.lookupString.contains('collect(toList())') })
+    checkResultByFile(getTestName(false) + "_after.java")
+  }
+
   public void testAllCollectors() {
     configureByTestName()
     myFixture.assertPreferredCompletionItems 0, 'collect', 'collect', 'collect(Collectors.toCollection())', 'collect(Collectors.toList())', 'collect(Collectors.toSet())'