[JVM_IR] Fix inline class default method codegen.

Do not coroutine transform static inline class replacements that
forward to a default interface suspend method. No boxing has to
take place on return (as the default interface method always
boxes) so we can simply forward the call.

^KT-49645 Fixed

compiler/fir/fir2ir/tests-gen/org/jetbrains/kotlin/test/runners/codegen/FirBlackBoxCodegenTestGenerated.java

@@ -9828,6 +9828,12 @@ public class FirBlackBoxCodegenTestGenerated extends AbstractFirBlackBoxCodegenT
             runTest("compiler/testData/codegen/box/coroutines/kt49168.kt");
         }
 
+        @Test
+        @TestMetadata("kt49645.kt")
+        public void testKt49645() throws Exception {
+            runTest("compiler/testData/codegen/box/coroutines/kt49645.kt");
+        }
+
         @Test
         @TestMetadata("lastExpressionIsLoop.kt")
         public void testLastExpressionIsLoop() throws Exception {

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

@@ -21,10 +21,7 @@ import org.jetbrains.kotlin.config.LanguageFeature
 import org.jetbrains.kotlin.ir.declarations.*
 import org.jetbrains.kotlin.ir.expressions.*
 import org.jetbrains.kotlin.ir.types.*
-import org.jetbrains.kotlin.ir.util.file
-import org.jetbrains.kotlin.ir.util.functions
-import org.jetbrains.kotlin.ir.util.isSuspend
-import org.jetbrains.kotlin.ir.util.parentAsClass
+import org.jetbrains.kotlin.ir.util.*
 import org.jetbrains.kotlin.psi.KtElement
 import org.jetbrains.org.objectweb.asm.MethodVisitor
 import org.jetbrains.org.objectweb.asm.Type
@@ -147,7 +144,15 @@ private val BRIDGE_ORIGINS = setOf(
 // These functions contain a single `suspend` tail call, the value of which should be returned as is
 // (i.e. if it's an unboxed inline class value, it should remain unboxed).
 internal fun IrFunction.isNonBoxingSuspendDelegation(): Boolean =
-    origin in BRIDGE_ORIGINS || isMultifileBridge() || isBridgeToSuspendImplMethod()
+    origin in BRIDGE_ORIGINS ||
+            isMultifileBridge() ||
+            isBridgeToSuspendImplMethod() ||
+            isStaticInlineClassReplacementForDefaultInterfaceMethod()
+
+// Suspend static inline class replacements for fake overrides have to be for interface methods as inline classes cannot have a
+// non-Object super type.
+fun IrFunction.isStaticInlineClassReplacementForDefaultInterfaceMethod(): Boolean =
+    isStaticInlineClassReplacement && this is IrSimpleFunction && (attributeOwnerId as IrSimpleFunction).isFakeOverride
 
 fun IrFunction.shouldContainSuspendMarkers(): Boolean = !isNonBoxingSuspendDelegation() &&
         // These functions also contain a single `suspend` tail call, but if it returns an unboxed inline class value,

compiler/testData/codegen/box/coroutines/kt49645.kt

@@ -0,0 +1,30 @@
+// WITH_STDLIB
+// WITH_COROUTINES
+// TARGET_BACKEND: JVM
+
+import helpers.*
+import kotlin.coroutines.*
+
+interface Cont1 {
+    suspend fun flaf() = "O"
+
+    suspend fun toResult(): Result<String> {
+        val x = flaf()
+        return Result.success(x + "K")
+    }
+}
+
+@JvmInline
+private value class ContImpl(val a: String) : Cont1
+
+fun builder(c: suspend () -> Unit) {
+    c.startCoroutine(EmptyContinuation)
+}
+
+fun box(): String {
+    var result = "FAIL"
+    builder {
+        result = ContImpl("A").toResult().getOrThrow()
+    }
+    return result
+}

compiler/tests-common-new/tests-gen/org/jetbrains/kotlin/test/runners/codegen/BlackBoxCodegenTestGenerated.java

@@ -9750,6 +9750,12 @@ public class BlackBoxCodegenTestGenerated extends AbstractBlackBoxCodegenTest {
             runTest("compiler/testData/codegen/box/coroutines/kt49168.kt");
         }
 
+        @Test
+        @TestMetadata("kt49645.kt")
+        public void testKt49645() throws Exception {
+            runTest("compiler/testData/codegen/box/coroutines/kt49645.kt");
+        }
+
         @Test
         @TestMetadata("lastExpressionIsLoop.kt")
         public void testLastExpressionIsLoop() throws Exception {

compiler/tests-common-new/tests-gen/org/jetbrains/kotlin/test/runners/codegen/IrBlackBoxCodegenTestGenerated.java

@@ -9828,6 +9828,12 @@ public class IrBlackBoxCodegenTestGenerated extends AbstractIrBlackBoxCodegenTes
             runTest("compiler/testData/codegen/box/coroutines/kt49168.kt");
         }
 
+        @Test
+        @TestMetadata("kt49645.kt")
+        public void testKt49645() throws Exception {
+            runTest("compiler/testData/codegen/box/coroutines/kt49645.kt");
+        }
+
         @Test
         @TestMetadata("lastExpressionIsLoop.kt")
         public void testLastExpressionIsLoop() throws Exception {

compiler/tests-gen/org/jetbrains/kotlin/codegen/LightAnalysisModeTestGenerated.java

@@ -7638,6 +7638,11 @@ public class LightAnalysisModeTestGenerated extends AbstractLightAnalysisModeTes
             runTest("compiler/testData/codegen/box/coroutines/kt46813.kt");
         }
 
+        @TestMetadata("kt49645.kt")
+        public void testKt49645() throws Exception {
+            runTest("compiler/testData/codegen/box/coroutines/kt49645.kt");
+        }
+
         @TestMetadata("lastExpressionIsLoop.kt")
         public void testLastExpressionIsLoop() throws Exception {
             runTest("compiler/testData/codegen/box/coroutines/lastExpressionIsLoop.kt");

native/native.tests/tests-gen/org/jetbrains/kotlin/konan/blackboxtest/NativeExtBlackBoxTestGenerated.java

@@ -7730,6 +7730,12 @@ public class NativeExtBlackBoxTestGenerated extends AbstractNativeBlackBoxTest {
                 runTest("compiler/testData/codegen/box/coroutines/kt49168.kt");
             }
 
+            @Test
+            @TestMetadata("kt49645.kt")
+            public void testKt49645() throws Exception {
+                runTest("compiler/testData/codegen/box/coroutines/kt49645.kt");
+            }
+
             @Test
             @TestMetadata("lastExpressionIsLoop.kt")
             public void testLastExpressionIsLoop() throws Exception {