keep annotations for explicit to var fixes (IDEA-193876)

java/java-impl/src/META-INF/JavaPlugin.xml

@@ -569,7 +569,7 @@
                      groupBundle="messages.InspectionsBundle"
                      groupKey="group.names.declaration.redundancy" enabledByDefault="true" level="INFORMATION"
                      implementationClass="com.intellij.codeInspection.lambda.RedundantLambdaParameterTypeInspection"
-                     displayName="Remove redundant lambda parameter types"/>
+                     displayName="Redundant lambda parameter types"/>
     <localInspection groupPath="Java" language="JAVA" shortName="ReplaceInefficientStreamCount"
                      groupBundle="messages.InspectionsBundle"
                      groupKey="group.names.performance.issues" enabledByDefault="true" level="WARNING"

java/java-impl/src/com/intellij/codeInspection/lambda/RedundantLambdaParameterTypeInspection.java

@@ -71,8 +71,9 @@ public class RedundantLambdaParameterTypeInspection extends AbstractBaseJavaLoca
   private static void removeTypes(PsiLambdaExpression lambdaExpression) {
     if (lambdaExpression != null) {
       final PsiParameter[] parameters = lambdaExpression.getParameterList().getParameters();
-      if (Arrays.stream(parameters).anyMatch(parameter -> parameter.hasModifierProperty(PsiModifier.FINAL) || 
-                                                          AnonymousCanBeLambdaInspection.hasRuntimeAnnotations(parameter,Collections.emptySet()))) {
+      if (PsiUtil.isLanguageLevel11OrHigher(lambdaExpression) &&
+          Arrays.stream(parameters).anyMatch(parameter -> parameter.hasModifierProperty(PsiModifier.FINAL) || 
+                                                          parameter.getAnnotations().length > 0)) {
         for (PsiParameter parameter : parameters) {
           PsiTypeElement element = parameter.getTypeElement();
           if (element != null) {

java/java-psi-impl/src/com/intellij/psi/impl/source/PsiTypeElementImpl.java

@@ -312,7 +312,10 @@ public class PsiTypeElementImpl extends CompositePsiElement implements PsiTypeEl
   @Override
   public PsiElement replace(@NotNull PsiElement newElement) throws IncorrectOperationException {
     // neighbouring type annotations are logical part of this type element and should be dropped
-    PsiImplUtil.markTypeAnnotations(this);
+    //if replacement is `var`, annotations should be left as they are not inferred from the right side of the assignment
+    if (!(newElement instanceof PsiTypeElement) || !((PsiTypeElement)newElement).isInferredType()) {
+      PsiImplUtil.markTypeAnnotations(this);
+    }
     PsiElement result = super.replace(newElement);
     if (result instanceof PsiTypeElement) {
       PsiImplUtil.deleteTypeAnnotations((PsiTypeElement)result);

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/quickFix/explicit2var/afterForeach.java

@@ -1,6 +1,7 @@
 // "Replace explicit type with 'var'" "true"
 class Main {
     void m(String[] args) {
-        for (var arg : args) ;
+        for (@Anno var arg : args) ;
     }
-}
+}
+@interface Anno {}

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/quickFix/explicit2var/afterNewArrayExpression.java

@@ -1,6 +1,7 @@
 // "Replace explicit type with 'var'" "true"
 class Main {
   {
-      var args = new String[42];
+    @Anno var args = new String[42];
   }
-}
+}
+@interface Anno {}

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/quickFix/explicit2var/beforeForeach.java

@@ -1,6 +1,7 @@
 // "Replace explicit type with 'var'" "true"
 class Main {
     void m(String[] args) {
-        for (<caret>String arg : args) ;
+        for (@Anno <caret>String arg : args) ;
     }
-}
+}
+@interface Anno {}

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/quickFix/explicit2var/beforeNewArrayExpression.java

@@ -1,6 +1,7 @@
 // "Replace explicit type with 'var'" "true"
 class Main {
   {
-    <caret>String[] args = new String[42];
+    @Anno <caret>String[] args = new String[42];
   }
-}
+}
+@interface Anno {}