TrivialFunctionalExpressionUsageInspection: disable for multi-statement lambda in "for" init/update

java/java-analysis-impl/src/com/intellij/codeInspection/bytecodeAnalysis/BytecodeAnalysisIndex.java

@@ -53,7 +53,7 @@ public class BytecodeAnalysisIndex extends ScalarIndexExtension<Bytes> {
   private static final ID<Bytes, Void> NAME = ID.create("bytecodeAnalysis");
   private static final HKeyDescriptor KEY_DESCRIPTOR = new HKeyDescriptor();
   private static final VirtualFileGist<Map<Bytes, HEquations>> ourGist = GistManager.getInstance().newVirtualFileGist(
-    "BytecodeAnalysisIndex", 4, new HEquationsExternalizer(), new ClassDataIndexer());
+    "BytecodeAnalysisIndex", 5, new HEquationsExternalizer(), new ClassDataIndexer());
 
   @NotNull
   @Override

java/java-analysis-impl/src/com/intellij/codeInspection/bytecodeAnalysis/PurityAnalysis.java

@@ -556,9 +556,6 @@ final class HardCodedPurity {
     // Maybe overloaded and be not pure, but this would be definitely bad code style
     // Used in Throwable(Throwable) ctor, so this helps to infer purity of many exception constructors
     new Method("java/lang/Throwable", "toString", "()Ljava/lang/String;"),
-    // Declared in final class StringBuilder
-    new Method("java/lang/StringBuilder", "toString", "()Ljava/lang/String;"),
-    new Method("java/lang/StringBuffer", "toString", "()Ljava/lang/String;"),
     // Native
     new Method("java/lang/Object", "getClass", "()Ljava/lang/Class;"),
     new Method("java/lang/Class", "getComponentType", "()Ljava/lang/Class;"),
@@ -596,7 +593,8 @@ final class HardCodedPurity {
   }
 
   static boolean isPureMethod(Key key) {
-    return pureMethods.contains(key.method);
+    return key.method.methodName.equals("toString") && key.method.methodDesc.equals("()Ljava/lang/String;") ||
+           pureMethods.contains(key.method);
   }
 
   static boolean isOwnedField(FieldInsnNode fieldInsn) {

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/quickFix/trivialFunctionalExpressionUsage/beforeBlockLambdaForInit.java

@@ -0,0 +1,13 @@
+// "Replace method call on lambda with lambda body" "false"
+
+public class Main {
+  public static void main(String[] args) {
+    int i = 0;
+    for (((Runnable) (() -> {
+      System.out.println("Hello");
+      System.out.println("World");
+    })).r<caret>un(); i < 10; ) {
+      System.out.println(i++);
+    }
+  }
+}

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/quickFix/trivialFunctionalExpressionUsage/beforeBlockLambdaForUpdate.java

@@ -0,0 +1,13 @@
+// "Replace method call on lambda with lambda body" "false"
+
+public class Main {
+  public static void main(String[] args) {
+    for (int i = 0; i < 10; ((Runnable) (() -> {
+      System.out.println("Hello");
+      System.out.println("World");
+      return;
+    })).ru<caret>n()) {
+      System.out.println(i++);
+    }
+  }
+}

plugins/InspectionGadgets/src/com/intellij/codeInspection/TrivialFunctionalExpressionUsageInspection.java

@@ -75,8 +75,13 @@ public class TrivialFunctionalExpressionUsageInspection extends BaseJavaBatchLoc
                 return true;
               }
             }
-            else {
+          }
-              return true;
+
+          if(callParent instanceof PsiExpressionStatement) {
+            PsiElement statementParent = callParent.getParent();
+            // Disable in "for" initialization or update
+            if(statementParent instanceof PsiForStatement && callParent != ((PsiForStatement)statementParent).getBody()) {
+              return false;
             }
           }