[FIR2IR] Avoid converting arguments of dynamic array set twice

^KT-63593 Fixed


Merge-request: KT-MR-13152
Merged-by: Nikolay Lunyak <Nikolay.Lunyak@jetbrains.com>

compiler/fir/fir2ir/src/org/jetbrains/kotlin/fir/backend/Fir2IrVisitor.kt

@@ -557,7 +557,7 @@ class Fir2IrVisitor(
             functionCall.calleeReference.name == OperatorNameConventions.SET &&
             functionCall.calleeReference.source?.kind == KtFakeSourceElementKind.ArrayAccessNameReference
         ) {
-            return convertToIrArrayAccessDynamicCall(functionCall)
+            return convertToIrArraySetDynamicCall(functionCall)
         }
         return convertToIrCall(functionCall, dynamicOperator = null)
     }
@@ -578,25 +578,24 @@ class Fir2IrVisitor(
         )
     }
 
-    private fun convertToIrArrayAccessDynamicCall(functionCall: FirFunctionCall): IrExpression {
-        val explicitReceiverExpression = convertToIrCall(
-            functionCall, dynamicOperator = IrDynamicOperator.ARRAY_ACCESS
-        )
-        if (explicitReceiverExpression is IrDynamicOperatorExpression) {
-            explicitReceiverExpression.arguments.removeLast()
+    private fun convertToIrArraySetDynamicCall(functionCall: FirFunctionCall): IrExpression {
+        // `functionCall` has the form of `myDynamic.set(key1, key2, ..., newValue)`.
+        // The resulting IR expects something like `myDynamic.ARRAY_ACCESS(key1, key2, ...).EQ(newValue)`.
+        // Instead of constructing a `FirFunctionCall` for `get()` (the true `ARRAY_ACCESS`), and a new
+        // call for `set()` (`EQ`), let's convert the whole thing as `ARRAY_ACCESS`, including
+        // `newValue`, and then manually move it to a newly constructed EQ call.
+        val arraySetAsGenericDynamicAccess = convertToIrCall(functionCall, IrDynamicOperator.ARRAY_ACCESS) as? IrDynamicOperatorExpression
+            ?: error("Converting dynamic array access should have resulted in IrDynamicOperatorExpression")
+        val arraySetNewValue = arraySetAsGenericDynamicAccess.arguments.removeLast()
+        return IrDynamicOperatorExpressionImpl(
+            arraySetAsGenericDynamicAccess.startOffset,
+            arraySetAsGenericDynamicAccess.endOffset,
+            arraySetAsGenericDynamicAccess.type,
+            IrDynamicOperator.EQ,
+        ).apply {
+            receiver = arraySetAsGenericDynamicAccess
+            arguments.add(arraySetNewValue)
         }
-        val result = callGenerator.convertToIrCall(
-            functionCall, functionCall.resolvedType, explicitReceiverExpression,
-            dynamicOperator = IrDynamicOperator.EQ
-        )
-        if (result is IrDynamicOperatorExpression) {
-            val arguments = result.arguments
-            arguments[0] = arguments[arguments.lastIndex]
-            while (arguments.size > 1) {
-                arguments.removeLast()
-            }
-        }
-        return result
     }
 
     override fun visitFunctionCall(functionCall: FirFunctionCall, data: Any?): IrExpression = whileAnalysing(session, functionCall) {

js/js.tests/tests-gen/org/jetbrains/kotlin/js/test/fir/FirJsBoxTestGenerated.java

@@ -1738,6 +1738,12 @@ public class FirJsBoxTestGenerated extends AbstractFirJsBoxTest {
             runTest("js/js.translator/testData/box/dynamic/compareTo.kt");
         }
 
+        @Test
+        @TestMetadata("dynamicArraySetWithLambda.kt")
+        public void testDynamicArraySetWithLambda() throws Exception {
+            runTest("js/js.translator/testData/box/dynamic/dynamicArraySetWithLambda.kt");
+        }
+
         @Test
         @TestMetadata("equals.kt")
         public void testEquals() throws Exception {

js/js.tests/tests-gen/org/jetbrains/kotlin/js/test/fir/FirJsES6BoxTestGenerated.java

@@ -1738,6 +1738,12 @@ public class FirJsES6BoxTestGenerated extends AbstractFirJsES6BoxTest {
             runTest("js/js.translator/testData/box/dynamic/compareTo.kt");
         }
 
+        @Test
+        @TestMetadata("dynamicArraySetWithLambda.kt")
+        public void testDynamicArraySetWithLambda() throws Exception {
+            runTest("js/js.translator/testData/box/dynamic/dynamicArraySetWithLambda.kt");
+        }
+
         @Test
         @TestMetadata("equals.kt")
         public void testEquals() throws Exception {

js/js.tests/tests-gen/org/jetbrains/kotlin/js/test/ir/IrBoxJsES6TestGenerated.java

@@ -1738,6 +1738,12 @@ public class IrBoxJsES6TestGenerated extends AbstractIrBoxJsES6Test {
             runTest("js/js.translator/testData/box/dynamic/compareTo.kt");
         }
 
+        @Test
+        @TestMetadata("dynamicArraySetWithLambda.kt")
+        public void testDynamicArraySetWithLambda() throws Exception {
+            runTest("js/js.translator/testData/box/dynamic/dynamicArraySetWithLambda.kt");
+        }
+
         @Test
         @TestMetadata("equals.kt")
         public void testEquals() throws Exception {

js/js.tests/tests-gen/org/jetbrains/kotlin/js/test/ir/IrBoxJsTestGenerated.java

@@ -1738,6 +1738,12 @@ public class IrBoxJsTestGenerated extends AbstractIrBoxJsTest {
             runTest("js/js.translator/testData/box/dynamic/compareTo.kt");
         }
 
+        @Test
+        @TestMetadata("dynamicArraySetWithLambda.kt")
+        public void testDynamicArraySetWithLambda() throws Exception {
+            runTest("js/js.translator/testData/box/dynamic/dynamicArraySetWithLambda.kt");
+        }
+
         @Test
         @TestMetadata("equals.kt")
         public void testEquals() throws Exception {

js/js.translator/testData/box/dynamic/dynamicArraySetWithLambda.kt

@@ -0,0 +1,10 @@
+// ISSUE: KT-63593
+// WITH_STDLIB
+
+fun <T> jso(): T = mutableMapOf<String, String>() as T
+
+fun box(): String {
+    val obj = jso<dynamic>()
+    obj["a"] = run { "OK" }
+    return obj["a"]
+}