Fix inlining of tail call suspend function

When inlining tail-call suspend function to regular
suspend function in JS BE, don't forget to insert suspension point.
See KT-16951

js/js.ast/src/org/jetbrains/kotlin/js/backend/ast/metadata/metadataProperties.kt

@@ -77,6 +77,8 @@ var HasMetadata.sideEffects: SideEffectKind by MetadataProperty(default = SideEf
  */
 var JsExpression.isSuspend: Boolean by MetadataProperty(default = false)
 
+var JsExpression.isTailCallSuspend: Boolean by MetadataProperty(default = false)
+
 /**
  * Denotes a reference to coroutine's `result` field that contains result of
  * last suspended invocation.
@@ -100,7 +102,6 @@ var JsFunction.coroutineMetadata: CoroutineMetadata? by MetadataProperty(default
 
 class CoroutineMetadata(
         val doResumeName: JsName,
-        val resumeName: JsName,
         val stateName: JsName,
         val exceptionStateName: JsName,
         val finallyPathName: JsName,

js/js.inliner/src/org/jetbrains/kotlin/js/inline/util/rewriters/ReturnReplacingVisitor.kt

@@ -43,9 +43,13 @@ class ReturnReplacingVisitor(
 
         ctx.removeMe()
 
+        val returnExpression = x.expression
         val returnReplacement = getReturnReplacement(x.expression)
         if (returnReplacement != null) {
-            ctx.addNext(JsExpressionStatement(returnReplacement).apply { synthetic = true })
+            if (returnExpression != null && returnExpression.isTailCallSuspend) {
+                returnReplacement.isSuspend = true
+            }
+            ctx.addNext(JsExpressionStatement(returnReplacement))
         }
 
         if (breakLabel != null) {
@@ -68,6 +72,7 @@ class ReturnReplacingVisitor(
 
     fun processCoroutineResult(expression: JsExpression?): JsExpression? {
         if (!isSuspend) return expression
+        if (expression != null && expression.isTailCallSuspend) return expression
         val lhs = JsNameRef("\$\$coroutineResult\$\$", JsAstUtils.stateMachineReceiver()).apply { coroutineResult = true }
         return JsAstUtils.assignment(lhs, expression ?: Namer.getUndefinedExpression())
     }

js/js.tests/test/org/jetbrains/kotlin/js/test/semantics/JsCodegenBoxTestGenerated.java

@@ -6298,6 +6298,12 @@ public class JsCodegenBoxTestGenerated extends AbstractJsCodegenBoxTest {
                 String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/box/coroutines/tailOperations/suspendWithWhen.kt");
                 doTest(fileName);
             }
+
+            @TestMetadata("tailInlining.kt")
+            public void testTailInlining() throws Exception {
+                String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/box/coroutines/tailOperations/tailInlining.kt");
+                doTest(fileName);
+            }
         }
 
         @TestMetadata("compiler/testData/codegen/box/coroutines/unitTypeReturn")

js/js.translator/src/org/jetbrains/kotlin/js/translate/callTranslator/CallTranslator.kt

@@ -22,10 +22,7 @@ import org.jetbrains.kotlin.descriptors.FunctionDescriptor
 import org.jetbrains.kotlin.descriptors.VariableDescriptor
 import org.jetbrains.kotlin.js.backend.ast.JsExpression
 import org.jetbrains.kotlin.js.backend.ast.JsNameRef
-import org.jetbrains.kotlin.js.backend.ast.metadata.SideEffectKind
-import org.jetbrains.kotlin.js.backend.ast.metadata.coroutineResult
-import org.jetbrains.kotlin.js.backend.ast.metadata.isSuspend
-import org.jetbrains.kotlin.js.backend.ast.metadata.sideEffects
+import org.jetbrains.kotlin.js.backend.ast.metadata.*
 import org.jetbrains.kotlin.js.translate.context.TranslationContext
 import org.jetbrains.kotlin.js.translate.general.Translation
 import org.jetbrains.kotlin.js.translate.reference.CallArgumentTranslator
@@ -137,13 +134,18 @@ private fun translateFunctionCall(
                               inlineResolvedCall.resultingDescriptor, context)
     }
 
-    if (resolvedCall.resultingDescriptor.isSuspend && context.isInStateMachine) {
-        context.currentBlock.statements += JsAstUtils.asSyntheticStatement(callExpression.apply { isSuspend = true })
-        val coroutineRef = TranslationUtils.translateContinuationArgument(context, resolvedCall)
-        return context.defineTemporary(JsNameRef("\$\$coroutineResult\$\$", coroutineRef).apply {
-            sideEffects = SideEffectKind.DEPENDS_ON_STATE
-            coroutineResult = true
-        })
+    if (resolvedCall.resultingDescriptor.isSuspend) {
+        if (context.isInStateMachine) {
+            context.currentBlock.statements += JsAstUtils.asSyntheticStatement(callExpression.apply { isSuspend = true })
+            val coroutineRef = TranslationUtils.translateContinuationArgument(context, resolvedCall)
+            return context.defineTemporary(JsNameRef("\$\$coroutineResult\$\$", coroutineRef).apply {
+                sideEffects = SideEffectKind.DEPENDS_ON_STATE
+                coroutineResult = true
+            })
+        }
+        else {
+            callExpression.isTailCallSuspend = true
+        }
     }
     return callExpression
 }

js/js.translator/src/org/jetbrains/kotlin/js/translate/utils/utils.kt

@@ -159,7 +159,6 @@ fun JsFunction.fillCoroutineMetadata(
 
     coroutineMetadata = CoroutineMetadata(
             doResumeName = context.getNameForDescriptor(TranslationUtils.getCoroutineDoResumeFunction(context)),
-            resumeName = context.getNameForDescriptor(TranslationUtils.getCoroutineResumeFunction(context)),
             suspendObjectRef = ReferenceTranslator.translateAsValueReference(suspendPropertyDescriptor, context),
             baseClassRef = coroutineBaseClassRef,
             stateName = getCoroutinePropertyName("state"),