[FIR] Report NOT_YET_SUPPORTED_IN_INLINE for inlines inside inlines

lunakoly · Space Team · commit f466d32cbeeb · 2025-07-25T15:17:11.000Z
Specifically, for `inline` functions inside `inline` functions. Such
code is prohibited in K1 and was allowed by accident.

^KT-79013 Fixed
diff --git a/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/declaration/FirInlineBodyRegularClassChecker.kt b/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/declaration/FirInlineBodyRegularClassChecker.kt
@@ -15,7 +15,7 @@ import org.jetbrains.kotlin.fir.declarations.FirRegularClass
 object FirInlineBodyRegularClassChecker : FirRegularClassChecker(MppCheckerKind.Common) {
     context(context: CheckerContext, reporter: DiagnosticReporter)
     override fun check(declaration: FirRegularClass) {
-        if (FirInlineBodySimpleFunctionChecker.isInsideInlineContext() && !declaration.classKind.isSingleton) {
+        if (FirInlineBodySimpleFunctionChecker.isInsideInlineContext(declaration) && !declaration.classKind.isSingleton) {
             reporter.reportOn(declaration.source, FirErrors.NOT_YET_SUPPORTED_IN_INLINE, "Local classes")
         }
     }
diff --git a/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/declaration/FirInlineBodySimpleFunctionChecker.kt b/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/declaration/FirInlineBodySimpleFunctionChecker.kt
@@ -11,6 +11,7 @@ import org.jetbrains.kotlin.diagnostics.reportOn
 import org.jetbrains.kotlin.fir.analysis.checkers.MppCheckerKind
 import org.jetbrains.kotlin.fir.analysis.checkers.context.CheckerContext
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors
+import org.jetbrains.kotlin.fir.declarations.FirDeclaration
 import org.jetbrains.kotlin.fir.declarations.FirSimpleFunction
 import org.jetbrains.kotlin.fir.symbols.FirBasedSymbol
 import org.jetbrains.kotlin.fir.symbols.impl.FirAnonymousObjectSymbol
@@ -19,16 +20,20 @@ import org.jetbrains.kotlin.fir.symbols.impl.FirRegularClassSymbol
 object FirInlineBodySimpleFunctionChecker : FirSimpleFunctionChecker(MppCheckerKind.Common) {
     context(context: CheckerContext, reporter: DiagnosticReporter)
     override fun check(declaration: FirSimpleFunction) {
-        if (isInsideInlineContext()) {
+        if (isInsideInlineContext(declaration)) {
             reporter.reportOn(declaration.source, FirErrors.NOT_YET_SUPPORTED_IN_INLINE, "Local functions")
         }
     }
 
     context(context: CheckerContext)
-    fun isInsideInlineContext(): Boolean {
+    fun isInsideInlineContext(declaration: FirDeclaration): Boolean {
+        val outerInlineContext = when {
+            declaration == context.inlineFunctionBodyContext?.inlineFunction -> context.inlineFunctionBodyContext?.parentInlineContext
+            else -> context.inlineFunctionBodyContext
+        }
         for (it in context.containingDeclarations.asReversed()) {
             when {
-                it == context.inlineFunctionBodyContext?.inlineFunction?.symbol -> return true
+                it == outerInlineContext?.inlineFunction?.symbol -> return true
                 it.isObject -> return false
             }
         }
diff --git a/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/declaration/FirInlineDeclarationChecker.kt b/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/declaration/FirInlineDeclarationChecker.kt
@@ -62,6 +62,7 @@ object FirInlineDeclarationChecker : FirFunctionChecker(MppCheckerKind.Common) {
         val inlineFunction: FirFunction,
         val inlineFunEffectiveVisibility: EffectiveVisibility,
         override val session: FirSession,
+        val parentInlineContext: InlineFunctionBodyContext?,
     ) : SessionHolder {
         private val isEffectivelyPrivateApiFunction: Boolean = inlineFunEffectiveVisibility.privateApi
 
@@ -425,11 +426,16 @@ internal fun FirValueParameter.isInlinable(session: FirSession): Boolean {
     return !fullyExpandedType.isMarkedNullable && fullyExpandedType.functionTypeKind(session)?.isInlineable == true
 }
 
-fun createInlineFunctionBodyContext(function: FirFunction, session: FirSession): FirInlineDeclarationChecker.InlineFunctionBodyContext {
+fun createInlineFunctionBodyContext(
+    function: FirFunction,
+    session: FirSession,
+    parentInlineContext: FirInlineDeclarationChecker.InlineFunctionBodyContext?
+): FirInlineDeclarationChecker.InlineFunctionBodyContext {
     return FirInlineDeclarationChecker.InlineFunctionBodyContext(
         function,
         function.publishedApiEffectiveVisibility ?: function.effectiveVisibility,
         session,
+        parentInlineContext,
     )
 }
 
diff --git a/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/collectors/AbstractDiagnosticCollectorVisitor.kt b/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/collectors/AbstractDiagnosticCollectorVisitor.kt
@@ -342,7 +342,7 @@ abstract class AbstractDiagnosticCollectorVisitor(
         val oldInlinableParameterContext = context.inlinableParameterContext
         return try {
             if (isInline) {
-                val bodyContext = createInlineFunctionBodyContext(function, context.session)
+                val bodyContext = createInlineFunctionBodyContext(function, context.session, oldBodyContext)
                 val parameterContext = createInlinableParameterContext(function, context.session)
                 context = context.setInlineFunctionBodyContext(bodyContext).setInlinableParameterContext(parameterContext)
             }
diff --git a/compiler/testData/codegen/box/inline/nestedLabelsInlinedClashingAtFunctionsWithClosure.kt b/compiler/testData/codegen/box/inline/nestedLabelsInlinedClashingAtFunctionsWithClosure.kt
@@ -10,6 +10,7 @@ internal fun test(state: State) {
         "NOT_YET_SUPPORTED_IN_INLINE", // K1/JVM-only error
     )
     inline fun test3() {
+        @Suppress("NOT_YET_SUPPORTED_IN_INLINE") // K2/ANY error
         inline fun test2() {
             inline fun test1() {
                 loop@ for (i in 1..10) {
diff --git a/compiler/testData/diagnostics/nativeTests/localInsideInlineInsideLocal.fir.kt b/compiler/testData/diagnostics/nativeTests/localInsideInlineInsideLocal.fir.kt
@@ -5,7 +5,7 @@ inline fun topLevelInlineFun() {
     <!NOT_YET_SUPPORTED_IN_INLINE!>fun<!> localFun() {}
     localFun()
 
-    inline fun localInlineFun() {
+    <!NOT_YET_SUPPORTED_IN_INLINE!>inline<!> fun localInlineFun() {
         <!NOT_YET_SUPPORTED_IN_INLINE!>fun<!> localFun() {}
         localFun()
     }
diff --git a/compiler/testData/diagnostics/tests/localInsideInlineInsideLocal.fir.kt b/compiler/testData/diagnostics/tests/localInsideInlineInsideLocal.fir.kt
@@ -6,7 +6,7 @@ inline fun topLevelInlineFun() {
     <!NOT_YET_SUPPORTED_IN_INLINE!>fun<!> localFun() {}
     localFun()
 
-    <!NOT_YET_SUPPORTED_LOCAL_INLINE_FUNCTION!>inline<!> fun localInlineFun() {
+    <!NOT_YET_SUPPORTED_IN_INLINE, NOT_YET_SUPPORTED_LOCAL_INLINE_FUNCTION!>inline<!> fun localInlineFun() {
         <!NOT_YET_SUPPORTED_IN_INLINE!>fun<!> localFun() {}
         localFun()
     }
diff --git a/compiler/testData/diagnostics/testsWithJsStdLib/localInsideInlineInsideLocal.fir.kt b/compiler/testData/diagnostics/testsWithJsStdLib/localInsideInlineInsideLocal.fir.kt
@@ -5,7 +5,7 @@ inline fun topLevelInlineFun() {
     <!NOT_YET_SUPPORTED_IN_INLINE!>fun<!> localFun() {}
     localFun()
 
-    inline fun localInlineFun() {
+    <!NOT_YET_SUPPORTED_IN_INLINE!>inline<!> fun localInlineFun() {
         <!NOT_YET_SUPPORTED_IN_INLINE!>fun<!> localFun() {}
         localFun()
     }
diff --git a/js/js.translator/testData/box/labels/nestedLabelsInlinedClashingAtFunctionsWithClosure.kt b/js/js.translator/testData/box/labels/nestedLabelsInlinedClashingAtFunctionsWithClosure.kt
@@ -10,6 +10,7 @@ class State() {
 
 internal fun test(state: State) {
     inline fun test3() {
+        @Suppress("NOT_YET_SUPPORTED_IN_INLINE")
         inline fun test2() {
             inline fun test1() {
                 loop@ for (i in 1..10) {

Original file line number	Diff line number	Diff line change
`@@ -15,7 +15,7 @@ import org.jetbrains.kotlin.fir.declarations.FirRegularClass`
`15`	`15`	`object FirInlineBodyRegularClassChecker : FirRegularClassChecker(MppCheckerKind.Common) {`
`16`	`16`	`context(context: CheckerContext, reporter: DiagnosticReporter)`
`17`	`17`	`override fun check(declaration: FirRegularClass) {`
`18`		`- if (FirInlineBodySimpleFunctionChecker.isInsideInlineContext() && !declaration.classKind.isSingleton) {`
	`18`	`+ if (FirInlineBodySimpleFunctionChecker.isInsideInlineContext(declaration) && !declaration.classKind.isSingleton) {`
`19`	`19`	`reporter.reportOn(declaration.source, FirErrors.NOT_YET_SUPPORTED_IN_INLINE, "Local classes")`
`20`	`20`	`}`
`21`	`21`	`}`
Original file line number	Diff line number	Diff line change
`@@ -342,7 +342,7 @@ abstract class AbstractDiagnosticCollectorVisitor(`
`342`	`342`	`val oldInlinableParameterContext = context.inlinableParameterContext`
`343`	`343`	`return try {`
`344`	`344`	`if (isInline) {`
`345`		`- val bodyContext = createInlineFunctionBodyContext(function, context.session)`
	`345`	`+ val bodyContext = createInlineFunctionBodyContext(function, context.session, oldBodyContext)`
`346`	`346`	`val parameterContext = createInlinableParameterContext(function, context.session)`
`347`	`347`	`context = context.setInlineFunctionBodyContext(bodyContext).setInlinableParameterContext(parameterContext)`
`348`	`348`	`}`
Original file line number	Diff line number	Diff line change
`@@ -10,6 +10,7 @@ internal fun test(state: State) {`
`10`	`10`	`"NOT_YET_SUPPORTED_IN_INLINE", // K1/JVM-only error`
`11`	`11`	`)`
`12`	`12`	`inline fun test3() {`
	`13`	`+ @Suppress("NOT_YET_SUPPORTED_IN_INLINE") // K2/ANY error`
`13`	`14`	`inline fun test2() {`
`14`	`15`	`inline fun test1() {`
`15`	`16`	`loop@ for (i in 1..10) {`
Original file line number	Diff line number	Diff line change
`@@ -5,7 +5,7 @@ inline fun topLevelInlineFun() {`
`5`	`5`	`<!NOT_YET_SUPPORTED_IN_INLINE!>fun<!> localFun() {}`
`6`	`6`	`localFun()`
`7`	`7`
`8`		`- inline fun localInlineFun() {`
	`8`	`+ <!NOT_YET_SUPPORTED_IN_INLINE!>inline<!> fun localInlineFun() {`
`9`	`9`	`<!NOT_YET_SUPPORTED_IN_INLINE!>fun<!> localFun() {}`
`10`	`10`	`localFun()`
`11`	`11`	`}`
Original file line number	Diff line number	Diff line change
`@@ -6,7 +6,7 @@ inline fun topLevelInlineFun() {`
`6`	`6`	`<!NOT_YET_SUPPORTED_IN_INLINE!>fun<!> localFun() {}`
`7`	`7`	`localFun()`
`8`	`8`
`9`		`- <!NOT_YET_SUPPORTED_LOCAL_INLINE_FUNCTION!>inline<!> fun localInlineFun() {`
	`9`	`+ <!NOT_YET_SUPPORTED_IN_INLINE, NOT_YET_SUPPORTED_LOCAL_INLINE_FUNCTION!>inline<!> fun localInlineFun() {`
`10`	`10`	`<!NOT_YET_SUPPORTED_IN_INLINE!>fun<!> localFun() {}`
`11`	`11`	`localFun()`
`12`	`12`	`}`