[FIR] Fix false positive "return required" for if/else with inlined return in branch

^KT-49289 Fixed

analysis/low-level-api-fir/tests/org/jetbrains/kotlin/analysis/low/level/api/fir/diagnostic/compiler/based/DiagnosisCompilerTestFE10TestdataTestGenerated.java

@@ -15843,6 +15843,12 @@ public class DiagnosisCompilerTestFE10TestdataTestGenerated extends AbstractDiag
                 runTest("compiler/testData/diagnostics/tests/inline/inlineReified.kt");
             }
 
+            @Test
+            @TestMetadata("inlinedReturnInBranch.kt")
+            public void testInlinedReturnInBranch() throws Exception {
+                runTest("compiler/testData/diagnostics/tests/inline/inlinedReturnInBranch.kt");
+            }
+
             @Test
             @TestMetadata("invoke.kt")
             public void testInvoke() throws Exception {

compiler/fir/analysis-tests/tests-gen/org/jetbrains/kotlin/test/runners/FirOldFrontendDiagnosticsTestGenerated.java

@@ -15843,6 +15843,12 @@ public class FirOldFrontendDiagnosticsTestGenerated extends AbstractFirDiagnosti
                 runTest("compiler/testData/diagnostics/tests/inline/inlineReified.kt");
             }
 
+            @Test
+            @TestMetadata("inlinedReturnInBranch.kt")
+            public void testInlinedReturnInBranch() throws Exception {
+                runTest("compiler/testData/diagnostics/tests/inline/inlinedReturnInBranch.kt");
+            }
+
             @Test
             @TestMetadata("invoke.kt")
             public void testInvoke() throws Exception {

compiler/fir/analysis-tests/tests-gen/org/jetbrains/kotlin/test/runners/FirOldFrontendDiagnosticsWithLightTreeTestGenerated.java

@@ -15843,6 +15843,12 @@ public class FirOldFrontendDiagnosticsWithLightTreeTestGenerated extends Abstrac
                 runTest("compiler/testData/diagnostics/tests/inline/inlineReified.kt");
             }
 
+            @Test
+            @TestMetadata("inlinedReturnInBranch.kt")
+            public void testInlinedReturnInBranch() throws Exception {
+                runTest("compiler/testData/diagnostics/tests/inline/inlinedReturnInBranch.kt");
+            }
+
             @Test
             @TestMetadata("invoke.kt")
             public void testInvoke() throws Exception {

compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/dfa/cfg/ControlFlowGraphBuilder.kt

@@ -641,6 +641,7 @@ class ControlFlowGraphBuilder {
         addNewSimpleNode(node)
         whenExitNodes.push(createWhenExitNode(whenExpression))
         whenBranchIndices.push(whenExpression.branches.mapIndexed { index, branch -> branch to index }.toMap())
+        notCompletedFunctionCalls.push(mutableListOf())
         levelCounter++
         return node
     }
@@ -676,6 +677,7 @@ class ControlFlowGraphBuilder {
         val whenExitNode = whenExitNodes.pop()
         // exit from last condition node still on stack
         // we should remove it
+        notCompletedFunctionCalls.pop().forEach(::completeFunctionCall)
         val lastWhenConditionExit = lastNodes.pop()
         val syntheticElseBranchNode = if (!whenExpression.isProperlyExhaustive) {
             createWhenSyntheticElseBranchNode(whenExpression).apply {
@@ -985,7 +987,7 @@ class ControlFlowGraphBuilder {
         catchNodeStorages.pop()
         val catchExitNodes = catchExitNodeStorages.pop()
         val tryMainExitNode = tryMainExitNodes.pop()
-        
+
         notCompletedFunctionCalls.pop().forEach(::completeFunctionCall)
 
         val node = tryExitNodes.pop()
@@ -1396,14 +1398,15 @@ class ControlFlowGraphBuilder {
             tryExitNodes.top().fir.finallyBlock == null -> {
                 // (3)... without finally ...(4)
                 // Either in try-main or catch.
-                if (tryMainExitNodes.top().followingNodes.isNotEmpty()) {
+                val tryMainExitNode = tryMainExitNodes.top()
+                if (tryMainExitNode.followingNodes.isNotEmpty()) {
                     // (4)... in catch, i.e., re-throw.
                     exitTargetsForTry.top()
                 } else {
                     // (4)... in try-main. Route to exit of try main block.
                     // We already have edges from the exit of try main block to each catch clause.
                     // This edge makes the remaining part of try main block, e.g., following `when` branches, marked as dead.
-                    tryMainExitNodes.top()
+                    tryMainExitNode
                 }
             }
             // (3)... within finally.

compiler/testData/diagnostics/tests/inline/inlinedReturnInBranch.kt

@@ -0,0 +1,20 @@
+// FIR_IDENTICAL
+// https://youtrack.jetbrains.com/issue/KT-49289
+
+inline fun <T> myRun(f: () -> T): T = f()
+
+fun foo(): Int {
+    myRun {
+        return 24
+    }
+}
+
+fun bar(arg: Boolean): Int {
+    if (arg) {
+        return 42
+    } else {
+        myRun {
+            return 24
+        }
+    }
+}

compiler/testData/diagnostics/tests/inline/inlinedReturnInBranch.txt

@@ -0,0 +1,5 @@
+package
+
+public fun bar(/*0*/ arg: kotlin.Boolean): kotlin.Int
+public fun foo(): kotlin.Int
+public inline fun </*0*/ T> myRun(/*0*/ f: () -> T): T

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

@@ -15849,6 +15849,12 @@ public class DiagnosticTestGenerated extends AbstractDiagnosticTest {
                 runTest("compiler/testData/diagnostics/tests/inline/inlineReified.kt");
             }
 
+            @Test
+            @TestMetadata("inlinedReturnInBranch.kt")
+            public void testInlinedReturnInBranch() throws Exception {
+                runTest("compiler/testData/diagnostics/tests/inline/inlinedReturnInBranch.kt");
+            }
+
             @Test
             @TestMetadata("invoke.kt")
             public void testInvoke() throws Exception {