JVM IR: Don't generate line numbers and null checks in SAM wrapper constructors

compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/lower/SingleAbstractMethodLowering.kt

@@ -69,6 +69,10 @@ abstract class SingleAbstractMethodLowering(val context: CommonBackendContext) :
     protected open fun getWrappedFunctionType(klass: IrClass): IrType =
         klass.defaultType
 
+    protected open fun IrFunctionBuilder.setConstructorSourceRange(createFor: IrElement) {
+        setSourceRange(createFor)
+    }
+
     abstract val IrType.needEqualsHashCodeMethods: Boolean
 
     open val inInlineFunctionScope get() = allScopes.any { scope -> (scope.irElement as? IrFunction)?.isInline ?: false }
@@ -187,10 +191,10 @@ abstract class SingleAbstractMethodLowering(val context: CommonBackendContext) :
         }
 
         subclass.addConstructor {
-            origin = subclass.origin
+            origin = IrDeclarationOrigin.GENERATED_SAM_IMPLEMENTATION
             isPrimary = true
             visibility = wrapperVisibility
-            setSourceRange(createFor)
+            setConstructorSourceRange(createFor)
         }.apply {
             val parameter = addValueParameter {
                 name = field.name

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

@@ -18,7 +18,7 @@ import org.jetbrains.kotlin.backend.jvm.lower.isMultifileBridge
 import org.jetbrains.kotlin.backend.jvm.lower.suspendFunctionOriginal
 import org.jetbrains.kotlin.codegen.*
 import org.jetbrains.kotlin.codegen.AsmUtil.*
-import org.jetbrains.kotlin.codegen.DescriptorAsmUtil.*
+import org.jetbrains.kotlin.codegen.DescriptorAsmUtil.getNameForReceiverParameter
 import org.jetbrains.kotlin.codegen.coroutines.SuspensionPointKind
 import org.jetbrains.kotlin.codegen.coroutines.generateCoroutineSuspendedCheck
 import org.jetbrains.kotlin.codegen.inline.*
@@ -48,7 +48,8 @@ import org.jetbrains.kotlin.ir.util.*
 import org.jetbrains.kotlin.ir.visitors.IrElementVisitor
 import org.jetbrains.kotlin.name.FqName
 import org.jetbrains.kotlin.resolve.jvm.AsmTypes
-import org.jetbrains.kotlin.resolve.jvm.AsmTypes.*
+import org.jetbrains.kotlin.resolve.jvm.AsmTypes.JAVA_STRING_TYPE
+import org.jetbrains.kotlin.resolve.jvm.AsmTypes.OBJECT_TYPE
 import org.jetbrains.kotlin.resolve.jvm.jvmSignature.JvmMethodParameterKind
 import org.jetbrains.kotlin.resolve.jvm.jvmSignature.JvmMethodSignature
 import org.jetbrains.kotlin.types.TypeSystemCommonBackendContext
@@ -285,7 +286,9 @@ class ExpressionCodegen(
             irFunction.origin.isSynthetic ||
             // TODO: refine this condition to not generate nullability assertions on parameters
             //       corresponding to captured variables and anonymous object super constructor arguments
-            (irFunction is IrConstructor && irFunction.parentAsClass.isAnonymousObject) ||
+            (irFunction is IrConstructor &&
+                    (irFunction.parentAsClass.isAnonymousObject ||
+                            irFunction.parentAsClass.origin == IrDeclarationOrigin.GENERATED_SAM_IMPLEMENTATION)) ||
             // TODO: Implement this as a lowering, so that we can more easily exclude generated methods.
             irFunction.origin == JvmLoweredDeclarationOrigin.INLINE_CLASS_GENERATED_IMPL_METHOD ||
             // Although these are accessible from Java, the functions they bridge to already have the assertions.

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

@@ -12,6 +12,9 @@ import org.jetbrains.kotlin.backend.jvm.JvmBackendContext
 import org.jetbrains.kotlin.backend.jvm.ir.erasedUpperBound
 import org.jetbrains.kotlin.backend.jvm.ir.rawType
 import org.jetbrains.kotlin.descriptors.DescriptorVisibilities
+import org.jetbrains.kotlin.ir.IrElement
+import org.jetbrains.kotlin.ir.UNDEFINED_OFFSET
+import org.jetbrains.kotlin.ir.builders.declarations.IrFunctionBuilder
 import org.jetbrains.kotlin.ir.declarations.IrClass
 import org.jetbrains.kotlin.ir.declarations.IrDeclarationOrigin
 import org.jetbrains.kotlin.ir.declarations.IrFunction
@@ -47,6 +50,13 @@ private class JvmSingleAbstractMethodLowering(context: JvmBackendContext) : Sing
     override fun getWrappedFunctionType(klass: IrClass): IrType =
         klass.symbol.rawType(context as JvmBackendContext)
 
+    // The constructor of a SAM wrapper is non-synthetic and should not have line numbers.
+    // Otherwise the debugger will try to step into it.
+    override fun IrFunctionBuilder.setConstructorSourceRange(createFor: IrElement) {
+        startOffset = UNDEFINED_OFFSET
+        endOffset = UNDEFINED_OFFSET
+    }
+
     private val IrType.isKotlinFunInterface: Boolean
         get() = getClass()?.origin != IrDeclarationOrigin.IR_EXTERNAL_JAVA_DECLARATION_STUB