diff --git a/compiler/ir/backend.jvm/src/org/jetbrains/kotlin/backend/jvm/codegen/ExpressionCodegen.kt b/compiler/ir/backend.jvm/src/org/jetbrains/kotlin/backend/jvm/codegen/ExpressionCodegen.kt
index 72c0f2e4a6e..9b52ae4b9fc 100644
--- a/compiler/ir/backend.jvm/src/org/jetbrains/kotlin/backend/jvm/codegen/ExpressionCodegen.kt
+++ b/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)
diff --git a/compiler/ir/backend.jvm/src/org/jetbrains/kotlin/backend/jvm/lower/JvmOptimizationLowering.kt b/compiler/ir/backend.jvm/src/org/jetbrains/kotlin/backend/jvm/lower/JvmOptimizationLowering.kt
index 837168de29b..bb8fe1087dd 100644
--- a/compiler/ir/backend.jvm/src/org/jetbrains/kotlin/backend/jvm/lower/JvmOptimizationLowering.kt
+++ b/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)
                 }
             }
diff --git a/compiler/testData/codegen/bytecodeText/coercionToUnitOptimization/safeCallWithReturnValue.kt b/compiler/testData/codegen/bytecodeText/coercionToUnitOptimization/safeCallWithReturnValue.kt
index 00019742547..b9158e9a009 100644
--- a/compiler/testData/codegen/bytecodeText/coercionToUnitOptimization/safeCallWithReturnValue.kt
+++ b/compiler/testData/codegen/bytecodeText/coercionToUnitOptimization/safeCallWithReturnValue.kt
@@ -8,10 +8,5 @@ fun test(x: A?) {
     x?.foo()
 }
 
-// JVM_TEMPLATES
 // 2 POP
 // 0 ACONST_NULL
-
-// JVM_IR_TEMPLATES
-// 2 POP
-// 0 ACONST_NULL
\ No newline at end of file
diff --git a/compiler/testData/codegen/bytecodeText/coercionToUnitOptimization/safeLet.kt b/compiler/testData/codegen/bytecodeText/coercionToUnitOptimization/safeLet.kt
index ef7af973d3f..5eb27d2a884 100644
--- a/compiler/testData/codegen/bytecodeText/coercionToUnitOptimization/safeLet.kt
+++ b/compiler/testData/codegen/bytecodeText/coercionToUnitOptimization/safeLet.kt
@@ -19,9 +19,4 @@ fun test(ss: List<String?>) {
 // 0 INVOKESTATIC java/lang/Boolean\.valueOf
 // 0 CHECKCAST java/lang/Boolean
 // 0 ACONST_NULL
-
-// JVM_TEMPLATES
-// 2 POP
-
-// JVM_IR_TEMPLATES
 // 2 POP
diff --git a/compiler/testData/codegen/bytecodeText/inline/noFakeVariableForInlineOnlyFun.kt b/compiler/testData/codegen/bytecodeText/inline/noFakeVariableForInlineOnlyFun.kt
index 0b059f4f515..ab58701ee4b 100644
--- a/compiler/testData/codegen/bytecodeText/inline/noFakeVariableForInlineOnlyFun.kt
+++ b/compiler/testData/codegen/bytecodeText/inline/noFakeVariableForInlineOnlyFun.kt
@@ -1,5 +1,3 @@
-// IGNORE_BACKEND_FIR: JVM_IR
-
 @Suppress("INVISIBLE_REFERENCE", "INVISIBLE_MEMBER")
 @kotlin.internal.InlineOnly
 inline fun inlineOnlyFun(): Int {
diff --git a/compiler/testData/debug/stepping/whenConstant.kt b/compiler/testData/debug/stepping/whenConstant.kt
index a849cd6b5f8..f508da70f08 100644
--- a/compiler/testData/debug/stepping/whenConstant.kt
+++ b/compiler/testData/debug/stepping/whenConstant.kt
@@ -12,9 +12,12 @@ fun box() {
 }
 
 // JVM_IR and JVM backends have different heuristics for when to use a switch.
-// JVM_IR inlines constant value subject and folds unreachable branches.
 
 // LINENUMBERS
 // test.kt:4 box
+// LINENUMBERS JVM_IR
+// test.kt:5 box
+// test.kt:7 box
+// LINENUMBERS
 // test.kt:10 box
 // test.kt:12 box
\ No newline at end of file