ControlFlowBuilder.getExitPoint() now can return null if nothing was found #KT-10823 Fixed

Also #EA-73355 Fixed

compiler/frontend/src/org/jetbrains/kotlin/cfg/ControlFlowBuilder.kt

@@ -39,7 +39,7 @@ interface ControlFlowBuilder {
 
     fun exitLexicalScope(element: KtElement)
 
-    fun getExitPoint(labelElement: KtElement): Label
+    fun getExitPoint(labelElement: KtElement): Label?
     fun getConditionEntryPoint(labelElement: KtElement): Label
 
     // Declarations

compiler/frontend/src/org/jetbrains/kotlin/cfg/ControlFlowBuilderAdapter.kt

@@ -123,7 +123,7 @@ abstract class ControlFlowBuilderAdapter : ControlFlowBuilder {
         delegateBuilder.throwException(throwExpression, thrownValue)
     }
 
-    override fun getExitPoint(labelElement: KtElement): Label {
+    override fun getExitPoint(labelElement: KtElement): Label? {
         return delegateBuilder.getExitPoint(labelElement)
     }
 

compiler/frontend/src/org/jetbrains/kotlin/cfg/ControlFlowProcessor.kt

@@ -785,7 +785,7 @@ class ControlFlowProcessor(private val trace: BindingTrace) {
             val loop = getCorrespondingLoop(expression)
             if (loop != null) {
                 checkJumpDoesNotCrossFunctionBoundary(expression, loop)
-                builder.jump(builder.getExitPoint(loop), expression)
+                builder.getExitPoint(loop)?.let { builder.jump(it, expression) }
             }
         }
 

compiler/frontend/src/org/jetbrains/kotlin/cfg/pseudocode/ControlFlowInstructionsGenerator.kt

@@ -171,9 +171,9 @@ class ControlFlowInstructionsGenerator : ControlFlowBuilderAdapter() {
             return (blockInfo as LoopInfo).conditionEntryPoint
         }
 
-        override fun getExitPoint(labelElement: KtElement): Label {
-            val blockInfo = elementToBlockInfo[labelElement] ?: error(labelElement.text)
-            return blockInfo.exitPoint
+        override fun getExitPoint(labelElement: KtElement): Label? {
+            // It's quite possible to have null here, e.g. for non-local returns (see KT-10823)
+            return elementToBlockInfo[labelElement]?.exitPoint
         }
 
         private val currentScope: LexicalScope
@@ -217,7 +217,7 @@ class ControlFlowInstructionsGenerator : ControlFlowBuilderAdapter() {
         }
 
         override fun exitSubroutine(subroutine: KtElement): Pseudocode {
-            bindLabel(getExitPoint(subroutine))
+            getExitPoint(subroutine)?.let { bindLabel(it) }
             pseudocode.addExitInstruction(SubroutineExitInstruction(subroutine, currentScope, false))
             bindLabel(error)
             pseudocode.addErrorInstruction(SubroutineExitInstruction(subroutine, currentScope, true))
@@ -245,13 +245,13 @@ class ControlFlowInstructionsGenerator : ControlFlowBuilderAdapter() {
         }
 
         override fun returnValue(returnExpression: KtExpression, returnValue: PseudoValue, subroutine: KtElement) {
-            val exitPoint = getExitPoint(subroutine)
+            val exitPoint = getExitPoint(subroutine) ?: return
             handleJumpInsideTryFinally(exitPoint)
             add(ReturnValueInstruction(returnExpression, currentScope, exitPoint, returnValue))
         }
 
         override fun returnNoValue(returnExpression: KtReturnExpression, subroutine: KtElement) {
-            val exitPoint = getExitPoint(subroutine)
+            val exitPoint = getExitPoint(subroutine) ?: return
             handleJumpInsideTryFinally(exitPoint)
             add(ReturnNoValueInstruction(returnExpression, currentScope, exitPoint))
         }

compiler/testData/diagnostics/tests/controlFlowAnalysis/kt10823.kt

@@ -0,0 +1,33 @@
+fun find2(): Any? {
+    fun visit(element: Any) {
+        <!RETURN_NOT_ALLOWED!>return@find2 element<!>
+    }
+    return null
+}
+
+// For find(): AssertionError at ControlFlowInstructionsGeneratorWorker.getExitPoint()
+
+fun find(): Any? {
+    object : Any() {
+        fun visit(element: Any) {
+            <!RETURN_NOT_ALLOWED!>return@find element<!>
+        }
+    }
+    return null
+}
+
+fun find4(): Any? {
+    <!NOT_YET_SUPPORTED_IN_INLINE!>inline fun visit(element: Any) {
+        <!RETURN_NOT_ALLOWED!>return@find4 element<!>
+    }<!>
+    return null
+}
+
+fun find3(): Any? {
+    object : Any() {
+        <!NOTHING_TO_INLINE!>inline<!> fun visit(element: Any) {
+            <!RETURN_NOT_ALLOWED!>return@find3 element<!>
+        }
+    }
+    return null
+}

compiler/testData/diagnostics/tests/controlFlowAnalysis/kt10823.txt

@@ -0,0 +1,6 @@
+package
+
+public fun find(): kotlin.Any?
+public fun find2(): kotlin.Any?
+public fun find3(): kotlin.Any?
+public fun find4(): kotlin.Any?

compiler/tests/org/jetbrains/kotlin/checkers/DiagnosticsTestGenerated.java

@@ -2889,6 +2889,12 @@ public class DiagnosticsTestGenerated extends AbstractDiagnosticsTest {
                 doTest(fileName);
             }
 
+            @TestMetadata("kt10823.kt")
+            public void testKt10823() throws Exception {
+                String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/diagnostics/tests/controlFlowAnalysis/kt10823.kt");
+                doTest(fileName);
+            }
+
             @TestMetadata("kt1156.kt")
             public void testKt1156() throws Exception {
                 String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/diagnostics/tests/controlFlowAnalysis/kt1156.kt");