IDEA-168203 Follow-up: do not suggest if initializer may throw checked exception or accesses non-final variable

java/java-impl/src/com/intellij/codeInspection/streamMigration/CollectMigration.java

@@ -15,6 +15,7 @@
  */
 package com.intellij.codeInspection.streamMigration;
 
+import com.intellij.codeInspection.util.LambdaGenerationUtil;
 import com.intellij.openapi.diagnostic.Logger;
 import com.intellij.openapi.project.Project;
 import com.intellij.openapi.util.text.StringUtil;
@@ -174,6 +175,13 @@ class CollectMigration extends BaseStreamApiMigration {
     }
   }
 
+  @Contract("null -> false")
+  static boolean hasLambdaCompatibleEmptyInitializer(@Nullable PsiLocalVariable target) {
+    return target != null &&
+           ConstructionUtils.isEmptyCollectionInitializer(target.getInitializer()) &&
+           LambdaGenerationUtil.canBeUncheckedLambda(target.getInitializer());
+  }
+
   static boolean isUsedOutsideOf(PsiVariable collectionVariable, Collection<PsiElement> allowedParents) {
     return !ReferencesSearch.search(collectionVariable)
       .forEach(ref -> {
@@ -240,7 +248,7 @@ class CollectMigration extends BaseStreamApiMigration {
                    PsiMethodCallExpression addCall,
                    PsiLoopStatement loop,
                    InitializerUsageStatus status) {
-      super(target, loop, ConstructionUtils.isEmptyCollectionInitializer(target.getInitializer()) ? status : ControlFlowUtils.InitializerUsageStatus.UNKNOWN);
+      super(target, loop, hasLambdaCompatibleEmptyInitializer(target) ? status : ControlFlowUtils.InitializerUsageStatus.UNKNOWN);
       myTargetType = target.getType();
       myInitializer = target.getInitializer();
       myElement = element;
@@ -445,7 +453,7 @@ class CollectMigration extends BaseStreamApiMigration {
           PsiExpression body = LambdaUtil.extractSingleExpressionFromBody(lambda.getBody());
           if (ConstructionUtils.isEmptyCollectionInitializer(body)) {
             PsiLocalVariable variable = extractQualifierVariable(tb, qualifierCall);
-            if (variable != null && ConstructionUtils.isEmptyCollectionInitializer(variable.getInitializer())) {
+            if (hasLambdaCompatibleEmptyInitializer(variable)) {
               PsiType mapType = variable.getType();
               PsiType valueType = PsiUtil.substituteTypeParameter(mapType, CommonClassNames.JAVA_UTIL_MAP, 1, false);
               if (valueType == null) return null;
@@ -519,7 +527,7 @@ class CollectMigration extends BaseStreamApiMigration {
         return null;
       }
       PsiLocalVariable variable = extractQualifierVariable(tb, call);
-      if (variable == null || !ConstructionUtils.isEmptyCollectionInitializer(variable.getInitializer())) return null;
+      if (!hasLambdaCompatibleEmptyInitializer(variable)) return null;
       InitializerUsageStatus status = getInitializerUsageStatus(variable, tb.getMainLoop());
       return new ToMapTerminal(call, tb.getVariable(), variable, tb.getMainLoop(), status);
     }

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/quickFix/streamApiMigration/afterCollectCustomConstructor.java

@@ -16,6 +16,13 @@ public class Test {
     ArrayList<String> result3 = new ArrayList<>(input);
       input.stream().filter(s -> !s.isEmpty()).forEach(result3::add);
     System.out.println(result3);
+
+    // Non-final var used in initializer
+    int size = 5;
+    if(size < input.size()) size = input.size();
+    List<String> result4 = new ArrayList<>(size);
+      input.stream().filter(s -> !s.isEmpty()).forEach(result4::add);
+    System.out.println(result4);
   }
 
   void testSet(List<String> input) {

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/quickFix/streamApiMigration/beforeCollectCustomConstructor.java

@@ -29,6 +29,17 @@ public class Test {
       }
     }
     System.out.println(result3);
+
+    // Non-final var used in initializer
+    int size = 5;
+    if(size < input.size()) size = input.size();
+    List<String> result4 = new ArrayList<>(size);
+    for (String s : input) {
+      if(!s.isEmpty()) {
+        result4.add(s);
+      }
+    }
+    System.out.println(result4);
   }
 
   void testSet(List<String> input) {