JVM_IR fixes after review

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

@@ -646,11 +646,6 @@ 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(
@@ -1229,7 +1224,7 @@ class ExpressionCodegen(
             val afterStore = markNewLabel()
 
             val catchBody = clause.result
-            var catchBlockInfo = BlockInfo(data)
+            val catchBlockInfo = BlockInfo(data)
             catchBlockInfo.variables.add(VariableInfo(parameter, index, descriptorType, afterStore))
 
             val catchResult = catchBody.accept(this, catchBlockInfo)

compiler/ir/backend.jvm/src/org/jetbrains/kotlin/backend/jvm/lower/JvmOptimizationLowering.kt

@@ -322,7 +322,10 @@ class JvmOptimizationLowering(val context: JvmBackendContext) : FileLoweringPass
                                     initializer
                             }
                         is IrValueParameter ->
-                            return initializer
+                            return if (initializerValue.isAssignable)
+                                null
+                            else
+                                initializer
                     }
             }
 
@@ -394,9 +397,10 @@ class JvmOptimizationLowering(val context: JvmBackendContext) : FileLoweringPass
             }
 
             if (expression.origin == IrStatementOrigin.WHEN) {
-                // Don't optimize out 'when' subject - otherwise we might get somewhat weird debugging behavior.
+                // Don't optimize out 'when' subject initialized with a variable,
+                // otherwise we might get somewhat weird debugging behavior.
                 val subject = expression.statements.firstOrNull()
-                if (subject is IrVariable) {
+                if (subject is IrVariable && subject.initializer is IrGetValue) {
                     dontTouchTemporaryVals.add(subject)
                 }
             }