KT-22274 report error/warning on incorrect return target label

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

@@ -70,7 +70,7 @@ class ControlFlowInformationProvider private constructor(
     ) : this(
         declaration,
         trace,
-        ControlFlowProcessor(trace).generatePseudocode(declaration),
+        ControlFlowProcessor(trace, languageVersionSettings).generatePseudocode(declaration),
         languageVersionSettings,
         diagnosticSuppressor
     )

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

@@ -30,11 +30,14 @@ import org.jetbrains.kotlin.cfg.pseudocode.PseudocodeImpl
 import org.jetbrains.kotlin.cfg.pseudocode.instructions.eval.AccessTarget
 import org.jetbrains.kotlin.cfg.pseudocode.instructions.eval.InstructionWithValue
 import org.jetbrains.kotlin.cfg.pseudocode.instructions.eval.MagicKind
+import org.jetbrains.kotlin.config.LanguageFeature
+import org.jetbrains.kotlin.config.LanguageVersionSettings
 import org.jetbrains.kotlin.contracts.description.InvocationKind
 import org.jetbrains.kotlin.contracts.description.canBeRevisited
 import org.jetbrains.kotlin.contracts.description.isDefinitelyVisited
 import org.jetbrains.kotlin.descriptors.*
 import org.jetbrains.kotlin.descriptors.impl.AnonymousFunctionDescriptor
+import org.jetbrains.kotlin.diagnostics.Errors
 import org.jetbrains.kotlin.diagnostics.Errors.*
 import org.jetbrains.kotlin.lexer.KtToken
 import org.jetbrains.kotlin.lexer.KtTokens
@@ -63,7 +66,10 @@ import java.util.*
 
 typealias DeferredGenerator = (ControlFlowBuilder) -> Unit
 
-class ControlFlowProcessor(private val trace: BindingTrace) {
+class ControlFlowProcessor(
+    private val trace: BindingTrace,
+    private val languageVersionSettings: LanguageVersionSettings?
+) {
 
     private val builder: ControlFlowBuilder = ControlFlowInstructionsGenerator()
 
@@ -927,12 +933,10 @@ class ControlFlowProcessor(private val trace: BindingTrace) {
             val subroutine: KtElement?
             val labelName = expression.getLabelName()
             subroutine = if (labelElement != null && labelName != null) {
-                val labeledElement = trace.get(BindingContext.LABEL_TARGET, labelElement)
+                trace.get(BindingContext.LABEL_TARGET, labelElement)?.let { labeledElement ->
-                if (labeledElement != null) {
+                    val labeledKtElement = labeledElement as KtElement
-                    assert(labeledElement is KtElement)
+                    checkReturnLabelTarget(expression, labeledKtElement)
-                    labeledElement as KtElement?
+                    labeledKtElement
-                } else {
-                    null
                 }
             } else {
                 builder.returnSubroutine
@@ -951,6 +955,17 @@ class ControlFlowProcessor(private val trace: BindingTrace) {
             }
         }
 
+        private fun checkReturnLabelTarget(returnExpression: KtReturnExpression, labeledElement: KtElement) {
+            if (languageVersionSettings == null) return
+            if (labeledElement !is KtFunctionLiteral && labeledElement !is KtNamedFunction) {
+                if (languageVersionSettings.supportsFeature(LanguageFeature.RestrictReturnStatementTarget)) {
+                    trace.report(Errors.NOT_A_FUNCTION_LABEL.on(returnExpression))
+                } else {
+                    trace.report(Errors.NOT_A_FUNCTION_LABEL_WARNING.on(returnExpression))
+                }
+            }
+        }
+
         override fun visitParameter(parameter: KtParameter) {
             builder.declareParameter(parameter)
             val defaultValue = parameter.defaultValue

compiler/frontend/src/org/jetbrains/kotlin/cfg/pseudocode/PseudocodeUtil.java

@@ -89,7 +89,7 @@ public class PseudocodeUtil {
                 return false;
             }
         };
-        return new ControlFlowProcessor(mockTrace).generatePseudocode(declaration);
+        return new ControlFlowProcessor(mockTrace, null).generatePseudocode(declaration);
     }
 
     @Nullable

compiler/frontend/src/org/jetbrains/kotlin/diagnostics/Errors.java

@@ -819,6 +819,9 @@ public interface Errors {
     DiagnosticFactory0<KtExpressionWithLabel> BREAK_OR_CONTINUE_JUMPS_ACROSS_FUNCTION_BOUNDARY = DiagnosticFactory0.create(ERROR);
     DiagnosticFactory1<KtExpressionWithLabel, String> NOT_A_LOOP_LABEL = DiagnosticFactory1.create(ERROR);
 
+    DiagnosticFactory0<KtExpressionWithLabel> NOT_A_FUNCTION_LABEL = DiagnosticFactory0.create(ERROR);
+    DiagnosticFactory0<KtExpressionWithLabel> NOT_A_FUNCTION_LABEL_WARNING = DiagnosticFactory0.create(WARNING);
+
     // Control flow / Data flow
 
     DiagnosticFactory1<KtElement, List<TextRange>> UNREACHABLE_CODE = DiagnosticFactory1.create(

compiler/frontend/src/org/jetbrains/kotlin/diagnostics/rendering/DefaultErrorMessages.java

@@ -599,6 +599,9 @@ public class DefaultErrorMessages {
         MAP.put(BREAK_OR_CONTINUE_JUMPS_ACROSS_FUNCTION_BOUNDARY, "'break' or 'continue' jumps across a function or a class boundary");
         MAP.put(NOT_A_LOOP_LABEL, "The label ''{0}'' does not denote a loop", STRING);
 
+        MAP.put(NOT_A_FUNCTION_LABEL, "Target label does not denote a function");
+        MAP.put(NOT_A_FUNCTION_LABEL_WARNING, "Target label does not denote a function");
+
         MAP.put(ANONYMOUS_INITIALIZER_IN_INTERFACE, "Anonymous initializers are not allowed in interfaces");
         MAP.put(NULLABLE_SUPERTYPE, "A supertype cannot be nullable");
         MAP.put(DYNAMIC_SUPERTYPE, "A supertype cannot be dynamic");

compiler/testData/cli/jvm/apiVersionInvalid.out

@@ -1,3 +1,3 @@
 error: unknown API version: 239.42
-Supported API versions: 1.0, 1.1, 1.2, 1.3 (EXPERIMENTAL)
+Supported API versions: 1.0, 1.1, 1.2, 1.3 (EXPERIMENTAL), 1.4 (EXPERIMENTAL)
 COMPILATION_ERROR

compiler/testData/cli/jvm/languageVersionInvalid.out

@@ -1,3 +1,3 @@
 error: unknown language version: 239.42
-Supported language versions: 1.0, 1.1, 1.2, 1.3 (EXPERIMENTAL)
+Supported language versions: 1.0, 1.1, 1.2, 1.3 (EXPERIMENTAL), 1.4 (EXPERIMENTAL)
 COMPILATION_ERROR

compiler/testData/diagnostics/tests/controlStructures/notAFunctionLabel_after.kt

@@ -0,0 +1,62 @@
+// !LANGUAGE: +RestrictReturnStatementTarget
+
+@Target(AnnotationTarget.EXPRESSION)
+@Retention(AnnotationRetention.SOURCE)
+annotation class Ann
+
+fun testFunctionName() {
+    return@testFunctionName
+}
+
+fun testHighOrderFunctionName() {
+    run {
+        return@run
+    }
+}
+
+fun testLambdaLabel() =
+    lambda@ {
+        return@lambda
+    }
+
+fun testParenthesizedLambdaLabel() =
+    lambda@ ( {
+        return@lambda
+    } )
+
+fun testAnnotatedLambdaLabel() =
+    lambda@ @Ann {
+        return@lambda
+    }
+
+fun testLambdaMultipleLabels1() =
+    lambda1@ lambda2@ {
+        return@lambda1
+    }
+
+fun testLambdaMultipleLabels2() =
+    lambda1@ lambda2@ {
+        return@lambda2
+    }
+
+fun testAnonymousFunctionLabel() =
+    anonFun@ fun() {
+        return@anonFun
+    }
+
+fun testLoopLabelInReturn(xs: List<Int>) {
+    L@ for (x in xs) {
+        if (x > 0) <!NOT_A_FUNCTION_LABEL!>return@L<!>
+    }
+}
+
+fun testValLabelInReturn() {
+    L@ val fn = { <!NOT_A_FUNCTION_LABEL!>return@L<!> }
+    fn()
+}
+
+fun testHighOrderFunctionCallLabelInReturn() {
+    L@ run {
+        <!NOT_A_FUNCTION_LABEL!>return@L<!>
+    }
+}

compiler/testData/diagnostics/tests/controlStructures/notAFunctionLabel_after.txt

@@ -0,0 +1,20 @@
+package
+
+public fun testAnnotatedLambdaLabel(): () -> kotlin.Unit
+public fun testAnonymousFunctionLabel(): () -> kotlin.Unit
+public fun testFunctionName(): kotlin.Unit
+public fun testHighOrderFunctionCallLabelInReturn(): kotlin.Unit
+public fun testHighOrderFunctionName(): kotlin.Unit
+public fun testLambdaLabel(): () -> kotlin.Unit
+public fun testLambdaMultipleLabels1(): () -> kotlin.Unit
+public fun testLambdaMultipleLabels2(): () -> kotlin.Unit
+public fun testLoopLabelInReturn(/*0*/ xs: kotlin.collections.List<kotlin.Int>): kotlin.Unit
+public fun testParenthesizedLambdaLabel(): () -> kotlin.Unit
+public fun testValLabelInReturn(): kotlin.Unit
+
+@kotlin.annotation.Target(allowedTargets = {AnnotationTarget.EXPRESSION}) @kotlin.annotation.Retention(value = AnnotationRetention.SOURCE) public final annotation class Ann : kotlin.Annotation {
+    public constructor Ann()
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}

compiler/testData/diagnostics/tests/controlStructures/notAFunctionLabel_before.kt

@@ -0,0 +1,62 @@
+// !LANGUAGE: -RestrictReturnStatementTarget
+
+@Target(AnnotationTarget.EXPRESSION)
+@Retention(AnnotationRetention.SOURCE)
+annotation class Ann
+
+fun testFunctionName() {
+    return@testFunctionName
+}
+
+fun testHighOrderFunctionName() {
+    run {
+        return@run
+    }
+}
+
+fun testLambdaLabel() =
+    lambda@ {
+        return@lambda
+    }
+
+fun testParenthesizedLambdaLabel() =
+    lambda@ ( {
+        return@lambda
+    } )
+
+fun testAnnotatedLambdaLabel() =
+    lambda@ @Ann {
+        return@lambda
+    }
+
+fun testLambdaMultipleLabels1() =
+    lambda1@ lambda2@ {
+        return@lambda1
+    }
+
+fun testLambdaMultipleLabels2() =
+    lambda1@ lambda2@ {
+        return@lambda2
+    }
+
+fun testAnonymousFunctionLabel() =
+    anonFun@ fun() {
+        return@anonFun
+    }
+
+fun testLoopLabelInReturn(xs: List<Int>) {
+    L@ for (x in xs) {
+        if (x > 0) <!NOT_A_FUNCTION_LABEL_WARNING!>return@L<!>
+    }
+}
+
+fun testValLabelInReturn() {
+    L@ val fn = { <!NOT_A_FUNCTION_LABEL_WARNING!>return@L<!> }
+    fn()
+}
+
+fun testHighOrderFunctionCallLabelInReturn() {
+    L@ run {
+        <!NOT_A_FUNCTION_LABEL_WARNING!>return@L<!>
+    }
+}

compiler/testData/diagnostics/tests/controlStructures/notAFunctionLabel_before.txt

@@ -0,0 +1,20 @@
+package
+
+public fun testAnnotatedLambdaLabel(): () -> kotlin.Unit
+public fun testAnonymousFunctionLabel(): () -> kotlin.Unit
+public fun testFunctionName(): kotlin.Unit
+public fun testHighOrderFunctionCallLabelInReturn(): kotlin.Unit
+public fun testHighOrderFunctionName(): kotlin.Unit
+public fun testLambdaLabel(): () -> kotlin.Unit
+public fun testLambdaMultipleLabels1(): () -> kotlin.Unit
+public fun testLambdaMultipleLabels2(): () -> kotlin.Unit
+public fun testLoopLabelInReturn(/*0*/ xs: kotlin.collections.List<kotlin.Int>): kotlin.Unit
+public fun testParenthesizedLambdaLabel(): () -> kotlin.Unit
+public fun testValLabelInReturn(): kotlin.Unit
+
+@kotlin.annotation.Target(allowedTargets = {AnnotationTarget.EXPRESSION}) @kotlin.annotation.Retention(value = AnnotationRetention.SOURCE) public final annotation class Ann : kotlin.Annotation {
+    public constructor Ann()
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}

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

@@ -4130,6 +4130,16 @@ public class DiagnosticsTestGenerated extends AbstractDiagnosticsTest {
                 runTest("compiler/testData/diagnostics/tests/controlStructures/localReturnInsidePropertyAccessor.kt");
             }
 
+            @TestMetadata("notAFunctionLabel_after.kt")
+            public void testNotAFunctionLabel_after() throws Exception {
+                runTest("compiler/testData/diagnostics/tests/controlStructures/notAFunctionLabel_after.kt");
+            }
+
+            @TestMetadata("notAFunctionLabel_before.kt")
+            public void testNotAFunctionLabel_before() throws Exception {
+                runTest("compiler/testData/diagnostics/tests/controlStructures/notAFunctionLabel_before.kt");
+            }
+
             @TestMetadata("specialConstructsAndPlatformTypes.kt")
             public void testSpecialConstructsAndPlatformTypes() throws Exception {
                 runTest("compiler/testData/diagnostics/tests/controlStructures/specialConstructsAndPlatformTypes.kt");

compiler/tests/org/jetbrains/kotlin/checkers/javac/DiagnosticsUsingJavacTestGenerated.java

@@ -4130,6 +4130,16 @@ public class DiagnosticsUsingJavacTestGenerated extends AbstractDiagnosticsUsing
                 runTest("compiler/testData/diagnostics/tests/controlStructures/localReturnInsidePropertyAccessor.kt");
             }
 
+            @TestMetadata("notAFunctionLabel_after.kt")
+            public void testNotAFunctionLabel_after() throws Exception {
+                runTest("compiler/testData/diagnostics/tests/controlStructures/notAFunctionLabel_after.kt");
+            }
+
+            @TestMetadata("notAFunctionLabel_before.kt")
+            public void testNotAFunctionLabel_before() throws Exception {
+                runTest("compiler/testData/diagnostics/tests/controlStructures/notAFunctionLabel_before.kt");
+            }
+
             @TestMetadata("specialConstructsAndPlatformTypes.kt")
             public void testSpecialConstructsAndPlatformTypes() throws Exception {
                 runTest("compiler/testData/diagnostics/tests/controlStructures/specialConstructsAndPlatformTypes.kt");

compiler/util/src/org/jetbrains/kotlin/config/LanguageVersionSettings.kt

@@ -83,6 +83,8 @@ enum class LanguageFeature(
     RestrictRetentionForExpressionAnnotations(KOTLIN_1_3, kind = BUG_FIX),
     NoConstantValueAttributeForNonConstVals(KOTLIN_1_3, kind = BUG_FIX),
 
+    RestrictReturnStatementTarget(KOTLIN_1_4, kind = BUG_FIX),
+
     StrictJavaNullabilityAssertions(sinceVersion = null, defaultState = State.DISABLED),
     ProperIeee754Comparisons(sinceVersion = null, defaultState = State.DISABLED, kind = BUG_FIX),
 
@@ -185,7 +187,8 @@ enum class LanguageVersion(val major: Int, val minor: Int) : DescriptionAware {
     KOTLIN_1_0(1, 0),
     KOTLIN_1_1(1, 1),
     KOTLIN_1_2(1, 2),
-    KOTLIN_1_3(1, 3);
+    KOTLIN_1_3(1, 3),
+    KOTLIN_1_4(1, 4);
 
     val isStable: Boolean
         get() = this <= LATEST_STABLE

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/dsl/KotlinCommonOptions.kt

@@ -6,14 +6,14 @@ interface KotlinCommonOptions  : org.jetbrains.kotlin.gradle.dsl.KotlinCommonToo
 
     /**
      * Allow to use declarations only from the specified version of bundled libraries
-     * Possible values: "1.0", "1.1", "1.2", "1.3 (EXPERIMENTAL)"
+     * Possible values: "1.0", "1.1", "1.2", "1.3 (EXPERIMENTAL)", "1.4 (EXPERIMENTAL)"
      * Default value: null
      */
      var apiVersion: kotlin.String?
 
     /**
      * Provide source compatibility with specified language version
-     * Possible values: "1.0", "1.1", "1.2", "1.3 (EXPERIMENTAL)"
+     * Possible values: "1.0", "1.1", "1.2", "1.3 (EXPERIMENTAL)", "1.4 (EXPERIMENTAL)"
      * Default value: null
      */
      var languageVersion: kotlin.String?