Extract Function: Support implicit abnormal exits via Nothing-typed expressions

ChangeLog.md

@@ -242,6 +242,7 @@ These artifacts include extensions for the types available in the latter JDKs, s
 - [`KT-14128`](https://youtrack.jetbrains.com/issue/KT-14128), [`KT-13862`](https://youtrack.jetbrains.com/issue/KT-13862) Rename: Use qualified class name when looking for occurrences in non-code files
 - [`KT-6199`](https://youtrack.jetbrains.com/issue/KT-6199) Rename: Replace non-code class occurrences with new qualified name
 - [`KT-14182`](https://youtrack.jetbrains.com/issue/KT-14182) Move: Show error message on applying to enum entries
+- Extract Function: Support implicit abnormal exits via Nothing-typed expressions
 
 ##### New features
 

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

@@ -39,6 +39,8 @@ interface Pseudocode {
 
     val exitInstruction: SubroutineExitInstruction
 
+    val errorInstruction: SubroutineExitInstruction
+
     val sinkInstruction: SubroutineSinkInstruction
 
     val enterInstruction: SubroutineEnterInstruction

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

@@ -71,7 +71,7 @@ class PseudocodeImpl(override val correspondingElement: KtElement) : Pseudocode
 
     private var internalErrorInstruction: SubroutineExitInstruction? = null
 
-    private val errorInstruction: SubroutineExitInstruction
+    override val errorInstruction: SubroutineExitInstruction
         get() = internalErrorInstruction ?: throw AssertionError("Error instruction is read before initialization")
 
     private var postPrecessed = false

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

@@ -18,9 +18,11 @@ package org.jetbrains.kotlin.cfg.pseudocode
 
 import com.intellij.psi.util.PsiTreeUtil
 import org.jetbrains.kotlin.builtins.KotlinBuiltIns
+import org.jetbrains.kotlin.cfg.Label
 import org.jetbrains.kotlin.cfg.pseudocode.instructions.Instruction
 import org.jetbrains.kotlin.cfg.pseudocode.instructions.eval.*
 import org.jetbrains.kotlin.cfg.pseudocode.instructions.eval.MagicKind.*
+import org.jetbrains.kotlin.cfg.pseudocode.instructions.jumps.AbstractJumpInstruction
 import org.jetbrains.kotlin.cfg.pseudocode.instructions.jumps.ConditionalJumpInstruction
 import org.jetbrains.kotlin.cfg.pseudocode.instructions.jumps.ReturnValueInstruction
 import org.jetbrains.kotlin.cfg.pseudocode.instructions.jumps.ThrowExceptionInstruction
@@ -307,4 +309,7 @@ fun Pseudocode.getPseudocodeByElement(element: KtElement): Pseudocode? {
 
     localDeclarations.forEach { decl -> decl.body.getPseudocodeByElement(element)?.let { return it } }
     return null
-}
+}
+
+val Label.isJumpToError: Boolean
+    get() = resolveToInstruction() == pseudocode.errorInstruction

idea/src/org/jetbrains/kotlin/idea/refactoring/introduce/extractionEngine/extractableAnalysisUtil.kt

@@ -243,6 +243,8 @@ private fun ExtractionData.analyzeControlFlow(
                 when {
                     it !is ReturnValueInstruction && it !is ReturnNoValueInstruction && it.owner != pseudocode ->
                         null
+                    it is UnconditionalJumpInstruction && it.targetLabel.isJumpToError ->
+                        it
                     e != null && e !is KtBreakExpression && e !is KtContinueExpression ->
                         it.previousInstructions.firstOrNull()
                     else ->
@@ -268,7 +270,7 @@ private fun ExtractionData.analyzeControlFlow(
                         || element is KtContinueExpression) {
                     jumpExits.add(inst)
                 }
-                else if (element !is KtThrowExpression) {
+                else if (element !is KtThrowExpression && !inst.targetLabel.isJumpToError) {
                     defaultExits.add(inst)
                 }
             }

idea/testData/refactoring/extractFunction/controlFlow/throws/implicitThrow.kt

@@ -0,0 +1,7 @@
+// WITH_RUNTIME
+// PARAM_DESCRIPTOR: value-parameter a: kotlin.Int? defined in foo
+// PARAM_TYPES: kotlin.Int?
+fun foo(a: Int?): Int {
+    <selection>val n = a ?: error("")
+    return n + 1</selection>
+}

idea/testData/refactoring/extractFunction/controlFlow/throws/implicitThrow.kt.after

@@ -0,0 +1,11 @@
+// WITH_RUNTIME
+// PARAM_DESCRIPTOR: value-parameter a: kotlin.Int? defined in foo
+// PARAM_TYPES: kotlin.Int?
+fun foo(a: Int?): Int {
+    return i(a)
+}
+
+private fun i(a: Int?): Int {
+    val n = a ?: error("")
+    return n + 1
+}

idea/tests/org/jetbrains/kotlin/idea/refactoring/introduce/ExtractionTestGenerated.java

@@ -1682,6 +1682,12 @@ public class ExtractionTestGenerated extends AbstractExtractionTest {
                     doExtractFunctionTest(fileName);
                 }
 
+                @TestMetadata("implicitThrow.kt")
+                public void testImplicitThrow() throws Exception {
+                    String fileName = KotlinTestUtils.navigationMetadata("idea/testData/refactoring/extractFunction/controlFlow/throws/implicitThrow.kt");
+                    doExtractFunctionTest(fileName);
+                }
+
                 @TestMetadata("nonValuedReturnWithThrow.kt")
                 public void testNonValuedReturnWithThrow() throws Exception {
                     String fileName = KotlinTestUtils.navigationMetadata("idea/testData/refactoring/extractFunction/controlFlow/throws/nonValuedReturnWithThrow.kt");