Don't write synthetic arguments to LVT

compiler/ir/backend.jvm/src/org/jetbrains/kotlin/backend/jvm/codegen/ExpressionCodegen.kt

@@ -252,7 +252,9 @@ class ExpressionCodegen(
             writeValueParameterInLocalVariableTable(extensionReceiverParameter, startLabel, endLabel, true)
         }
         for (param in irFunction.valueParameters) {
-            writeValueParameterInLocalVariableTable(param, startLabel, endLabel, false)
+            if (!param.origin.isSynthetic) {
+                writeValueParameterInLocalVariableTable(param, startLabel, endLabel, false)
+            }
         }
     }
 

compiler/testData/codegen/bytecodeText/defaultArguments/noSyntheticParameters.kt

@@ -0,0 +1,15 @@
+// FILE: Foo.kt
+
+fun foo(param: String = "123") {}
+
+
+//TODO: align backends
+
+// JVM_TEMPLATES
+// 1 LOCALVARIABLE param
+// 1 LOCALVARIABLE
+
+// JVM_IR_TEMPLATES
+// 2 LOCALVARIABLE param
+// 2 LOCALVARIABLE
+

compiler/tests/org/jetbrains/kotlin/codegen/BytecodeTextTestGenerated.java

@@ -1584,6 +1584,11 @@ public class BytecodeTextTestGenerated extends AbstractBytecodeTextTest {
         public void testNoEmptyArray() throws Exception {
             runTest("compiler/testData/codegen/bytecodeText/defaultArguments/noEmptyArray.kt");
         }
+
+        @TestMetadata("noSyntheticParameters.kt")
+        public void testNoSyntheticParameters() throws Exception {
+            runTest("compiler/testData/codegen/bytecodeText/defaultArguments/noSyntheticParameters.kt");
+        }
     }
 
     @TestMetadata("compiler/testData/codegen/bytecodeText/directInvoke")

compiler/tests/org/jetbrains/kotlin/codegen/ir/IrBytecodeTextTestGenerated.java

@@ -1539,6 +1539,11 @@ public class IrBytecodeTextTestGenerated extends AbstractIrBytecodeTextTest {
         public void testNoEmptyArray() throws Exception {
             runTest("compiler/testData/codegen/bytecodeText/defaultArguments/noEmptyArray.kt");
         }
+
+        @TestMetadata("noSyntheticParameters.kt")
+        public void testNoSyntheticParameters() throws Exception {
+            runTest("compiler/testData/codegen/bytecodeText/defaultArguments/noSyntheticParameters.kt");
+        }
     }
 
     @TestMetadata("compiler/testData/codegen/bytecodeText/directInvoke")