JVM optimize out temporary variables in bytecode

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

@@ -28,6 +28,7 @@ import org.jetbrains.kotlin.codegen.inline.ReifiedTypeInliner.Companion.putNeedC
 import org.jetbrains.kotlin.codegen.inline.ReifiedTypeInliner.OperationKind.AS
 import org.jetbrains.kotlin.codegen.inline.ReifiedTypeInliner.OperationKind.SAFE_AS
 import org.jetbrains.kotlin.codegen.intrinsics.TypeIntrinsics
+import org.jetbrains.kotlin.codegen.optimization.temporaryVals.addTemporaryValInitMarker
 import org.jetbrains.kotlin.codegen.pseudoInsns.fakeAlwaysFalseIfeq
 import org.jetbrains.kotlin.codegen.pseudoInsns.fixStackAndJump
 import org.jetbrains.kotlin.codegen.signature.BothSignatureWriter
@@ -629,6 +630,9 @@ class ExpressionCodegen(
             initializer.markLineNumber(startOffset = true)
             value.materializeAt(varType, declaration.type)
             declaration.markLineNumber(startOffset = true)
+            if (declaration.isTemporaryVal()) {
+                mv.addTemporaryValInitMarker()
+            }
             mv.store(index, varType)
         } else if (declaration.isVisibleInLVT) {
             pushDefaultValueOnStack(varType, mv)
@@ -646,6 +650,11 @@ class ExpressionCodegen(
         return MaterialValue(this, type, expression.symbol.owner.realType)
     }
 
+    private fun IrValueDeclaration.isTemporaryVal() =
+        this is IrVariable &&
+                !this.isVar &&
+                this.origin == IrDeclarationOrigin.IR_TEMPORARY_VARIABLE
+
     internal fun genOrGetLocal(expression: IrExpression, type: Type, parameterType: IrType, data: BlockInfo): StackValue =
         if (expression is IrGetValue)
             StackValue.local(
@@ -766,7 +775,7 @@ class ExpressionCodegen(
         val index = frameMap.getIndex(irSymbol)
         if (index >= 0)
             return index
-        throw AssertionError("Non-mapped local declaration: $irSymbol\n in ${irFunction.dump()}")
+        throw AssertionError("Non-mapped local declaration: ${irSymbol.owner.dump()}\n in ${irFunction.dump()}")
     }
 
     private fun handlePlusMinus(expression: IrSetValue, value: IrExpression?, isMinus: Boolean): Boolean {