FIR IDE: new symbol/kind/pointer/resolver for SAM constructor

idea/idea-frontend-api/src/org/jetbrains/kotlin/idea/frontend/api/KtAnalysisSession.kt

@@ -29,6 +29,7 @@ import org.jetbrains.kotlin.psi.KtFile
 public abstract class KtAnalysisSession(final override val token: ValidityToken) : ValidityTokenOwner,
     KtSmartCastProviderMixIn,
     KtCallResolverMixIn,
+    KtSamResolverMixIn,
     KtDiagnosticProviderMixIn,
     KtScopeProviderMixIn,
     KtCompletionCandidateCheckerMixIn,
@@ -75,6 +76,9 @@ public abstract class KtAnalysisSession(final override val token: ValidityToken)
     internal val callResolver: KtCallResolver get() = callResolverImpl
     protected abstract val callResolverImpl: KtCallResolver
 
+    internal val samResolver: KtSamResolver get() = samResolverImpl
+    protected abstract val samResolverImpl: KtSamResolver
+
     internal val completionCandidateChecker: KtCompletionCandidateChecker get() = completionCandidateCheckerImpl
     protected abstract val completionCandidateCheckerImpl: KtCompletionCandidateChecker
 

idea/idea-frontend-api/src/org/jetbrains/kotlin/idea/frontend/api/components/KtSamResolver.kt

@@ -0,0 +1,22 @@
+/*
+ * Copyright 2010-2021 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
+ */
+
+package org.jetbrains.kotlin.idea.frontend.api.components
+
+import org.jetbrains.kotlin.idea.frontend.api.symbols.KtClassLikeSymbol
+import org.jetbrains.kotlin.idea.frontend.api.symbols.KtSamConstructorSymbol
+import org.jetbrains.kotlin.name.ClassId
+
+public abstract class KtSamResolver : KtAnalysisSessionComponent() {
+    public abstract fun getSamConstructor(ktClassLikeSymbol: KtClassLikeSymbol): KtSamConstructorSymbol?
+}
+
+public interface KtSamResolverMixIn : KtAnalysisSessionMixIn {
+    /**
+     * Returns [KtSamConstructorSymbol] if the given [KtClassLikeSymbol] is a functional interface type, a.k.a. SAM.
+     */
+    public fun KtClassLikeSymbol.getSamConstructor(): KtSamConstructorSymbol? =
+        analysisSession.samResolver.getSamConstructor(this)
+}

idea/idea-frontend-api/src/org/jetbrains/kotlin/idea/frontend/api/symbols/DebugSymbolRenderer.kt

@@ -85,6 +85,7 @@ public object DebugSymbolRenderer {
             val symbolTag = when (value) {
                 is KtClassLikeSymbol -> renderValue(value.classIdIfNonLocal ?: "<local>/${value.name}")
                 is KtFunctionSymbol -> renderValue(value.callableIdIfNonLocal ?: "<local>/${value.name}")
+                is KtSamConstructorSymbol -> renderValue(value.callableIdIfNonLocal ?: "<local>/${value.name}")
                 is KtConstructorSymbol -> "<constructor>"
                 is KtNamedSymbol -> renderValue(value.name)
                 is KtPropertyGetterSymbol -> "<getter>"

idea/idea-frontend-api/src/org/jetbrains/kotlin/idea/frontend/api/symbols/KtFunctionLikeSymbol.kt

@@ -9,7 +9,6 @@ import org.jetbrains.kotlin.idea.frontend.api.symbols.markers.*
 import org.jetbrains.kotlin.idea.frontend.api.symbols.pointers.KtSymbolPointer
 import org.jetbrains.kotlin.name.CallableId
 import org.jetbrains.kotlin.name.ClassId
-import org.jetbrains.kotlin.name.FqName
 
 public abstract class KtFunctionLikeSymbol : KtCallableSymbol(), KtSymbolWithKind {
     public abstract val valueParameters: List<KtValueParameterSymbol>
@@ -31,6 +30,12 @@ public abstract class KtAnonymousFunctionSymbol : KtFunctionLikeSymbol() {
     abstract override fun createPointer(): KtSymbolPointer<KtAnonymousFunctionSymbol>
 }
 
+public abstract class KtSamConstructorSymbol : KtFunctionLikeSymbol(), KtNamedSymbol {
+    final override val symbolKind: KtSymbolKind get() = KtSymbolKind.SAM_CONSTRUCTOR
+
+    abstract override fun createPointer(): KtSymbolPointer<KtSamConstructorSymbol>
+}
+
 public abstract class KtFunctionSymbol : KtFunctionLikeSymbol(),
     KtNamedSymbol,
     KtPossibleMemberSymbol,
@@ -64,4 +69,4 @@ public abstract class KtConstructorSymbol : KtFunctionLikeSymbol(),
     final override val receiverType: KtTypeAndAnnotations? get() = null
 
     abstract override fun createPointer(): KtSymbolPointer<KtConstructorSymbol>
-}
+}

idea/idea-frontend-api/src/org/jetbrains/kotlin/idea/frontend/api/symbols/KtSymbol.kt

@@ -67,6 +67,12 @@ public enum class KtSymbolOrigin {
      */
     JAVA,
 
+    /**
+     * A synthetic function that is called as a lambda argument when creating a SAM interface object, e.g.,
+     * ```
+     * val isEven = <caret>IntPredicate { it % 2 == 0 }
+     * ```
+     */
     SAM_CONSTRUCTOR,
 
     /**
@@ -102,4 +108,4 @@ public enum class KtSymbolOrigin {
      * @see KtBackingFieldSymbol
      */
     PROPERTY_BACKING_FIELD,
-}
+}

idea/idea-frontend-api/src/org/jetbrains/kotlin/idea/frontend/api/symbols/markers/KtSymbolWithKind.kt

@@ -15,6 +15,10 @@ public interface KtSymbolWithKind : KtSymbol {
 }
 
 public enum class KtSymbolKind {
-    TOP_LEVEL, MEMBER, LOCAL, ACCESSOR
+    TOP_LEVEL,
+    MEMBER,
+    LOCAL,
+    ACCESSOR,
+    SAM_CONSTRUCTOR,
 }
 

idea/idea-frontend-api/src/org/jetbrains/kotlin/idea/frontend/api/symbols/pointers/SymbolPointerExceptions.kt

@@ -6,4 +6,9 @@
 package org.jetbrains.kotlin.idea.frontend.api.symbols.pointers
 
 public class CanNotCreateSymbolPointerForLocalLibraryDeclarationException(description: String) :
-    IllegalStateException("Could not create a symbol pointer for local symbol $description")
+    IllegalStateException("Could not create a symbol pointer for local symbol $description")
+
+public class WrongSymbolForSamConstructor(symbolKind: String) :
+    IllegalStateException(
+        "For symbol with kind = KtSymbolKind.SAM_CONSTRUCTOR, KtSamConstructorSymbol should be created, but was $symbolKind"
+    )

idea/idea-frontend-fir/src/org/jetbrains/kotlin/idea/frontend/api/fir/KtFirAnalysisSession.kt

@@ -50,6 +50,8 @@ private constructor(
 
     override val callResolverImpl = KtFirCallResolver(this, token)
 
+    override val samResolverImpl = KtFirSamResolver(this, token)
+
     override val scopeProviderImpl by threadLocal { KtFirScopeProvider(this, firSymbolBuilder, project, firResolveState, token) }
 
     override val symbolProviderImpl =

idea/idea-frontend-fir/src/org/jetbrains/kotlin/idea/frontend/api/fir/KtSymbolByFirBuilder.kt

@@ -191,7 +191,13 @@ internal class KtSymbolByFirBuilder private constructor(
     inner class FunctionLikeSymbolBuilder {
         fun buildFunctionLikeSymbol(fir: FirFunction): KtFunctionLikeSymbol {
             return when (fir) {
-                is FirSimpleFunction -> buildFunctionSymbol(fir)
+                is FirSimpleFunction -> {
+                    if (fir.origin == FirDeclarationOrigin.SamConstructor) {
+                        buildSamConstructorSymbol(fir)
+                    } else {
+                        buildFunctionSymbol(fir)
+                    }
+                }
                 is FirConstructor -> buildConstructorSymbol(fir)
                 is FirAnonymousFunction -> buildAnonymousFunctionSymbol(fir)
                 else -> throwUnexpectedElementError(fir)
@@ -199,6 +205,7 @@ internal class KtSymbolByFirBuilder private constructor(
         }
 
         fun buildFunctionSymbol(fir: FirSimpleFunction): KtFirFunctionSymbol {
+            check(fir.origin != FirDeclarationOrigin.SamConstructor)
             return symbolsCache.cache(fir) { KtFirFunctionSymbol(fir, resolveState, token, this@KtSymbolByFirBuilder) }
         }
 
@@ -212,6 +219,11 @@ internal class KtSymbolByFirBuilder private constructor(
                 KtFirConstructorSymbol(originalFir, resolveState, token, this@KtSymbolByFirBuilder)
             }
         }
+
+        fun buildSamConstructorSymbol(fir: FirSimpleFunction): KtFirSamConstructorSymbol {
+            check(fir.origin == FirDeclarationOrigin.SamConstructor)
+            return symbolsCache.cache(fir) { KtFirSamConstructorSymbol(fir, resolveState, token, this@KtSymbolByFirBuilder) }
+        }
     }
 
     inner class VariableLikeSymbolBuilder {

idea/idea-frontend-fir/src/org/jetbrains/kotlin/idea/frontend/api/fir/components/KtFirSamResolver.kt

@@ -0,0 +1,66 @@
+/*
+ * Copyright 2010-2021 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
+ */
+
+package org.jetbrains.kotlin.idea.frontend.api.fir.components
+
+import org.jetbrains.kotlin.fir.FirSession
+import org.jetbrains.kotlin.fir.declarations.FirDeclarationOrigin
+import org.jetbrains.kotlin.fir.declarations.FirRegularClass
+import org.jetbrains.kotlin.fir.declarations.FirResolvePhase
+import org.jetbrains.kotlin.fir.declarations.FirSimpleFunction
+import org.jetbrains.kotlin.fir.resolve.ScopeSession
+import org.jetbrains.kotlin.fir.resolve.transformers.body.resolve.FirAbstractBodyResolveTransformer
+import org.jetbrains.kotlin.fir.resolve.transformers.body.resolve.FirBodyResolveTransformer
+import org.jetbrains.kotlin.idea.frontend.api.components.KtSamResolver
+import org.jetbrains.kotlin.idea.frontend.api.fir.KtFirAnalysisSession
+import org.jetbrains.kotlin.idea.frontend.api.fir.symbols.pointers.getClassLikeSymbol
+import org.jetbrains.kotlin.idea.frontend.api.symbols.KtClassLikeSymbol
+import org.jetbrains.kotlin.idea.frontend.api.symbols.KtSamConstructorSymbol
+import org.jetbrains.kotlin.idea.frontend.api.tokens.ValidityToken
+
+internal class KtFirSamResolver(
+    override val analysisSession: KtFirAnalysisSession,
+    override val token: ValidityToken,
+) : KtSamResolver(), KtFirAnalysisSessionComponent {
+
+    override fun getSamConstructor(ktClassLikeSymbol: KtClassLikeSymbol): KtSamConstructorSymbol? {
+        val classId = ktClassLikeSymbol.classIdIfNonLocal ?: return null
+        val owner = analysisSession.getClassLikeSymbol(classId) as? FirRegularClass ?: return null
+        val resolver = LocalSamResolver(analysisSession.rootModuleSession)
+        return resolver.getSamConstructor(owner)?.let {
+            analysisSession.firSymbolBuilder.functionLikeBuilder.buildSamConstructorSymbol(it)
+        }
+    }
+
+    private class LocalSamResolver(
+        private val firSession: FirSession,
+    ) {
+        private val scopeSession = ScopeSession()
+
+        // TODO: This transformer is not intended for actual transformations and
+        //  created here only to simplify access to SAM resolver in body resolve components
+        private val stubBodyResolveTransformer = object : FirBodyResolveTransformer(
+            session = firSession,
+            phase = FirResolvePhase.BODY_RESOLVE,
+            implicitTypeOnly = false,
+            scopeSession = scopeSession,
+        ) {}
+
+        private val bodyResolveComponents =
+            FirAbstractBodyResolveTransformer.BodyResolveTransformerComponents(
+                firSession,
+                scopeSession,
+                stubBodyResolveTransformer,
+                stubBodyResolveTransformer.context,
+            )
+
+        // TODO: this doesn't guarantee that the same synthetic function (as a SAM constructor) is created/returned
+        fun getSamConstructor(firClass: FirRegularClass): FirSimpleFunction? {
+            val samConstructor = bodyResolveComponents.samResolver.getSamConstructor(firClass) ?: return null
+            if (samConstructor.origin != FirDeclarationOrigin.SamConstructor) return null
+            return samConstructor
+        }
+    }
+}

idea/idea-frontend-fir/src/org/jetbrains/kotlin/idea/frontend/api/fir/components/KtFirSymbolContainingDeclarationProvider.kt

@@ -15,7 +15,6 @@ import org.jetbrains.kotlin.idea.frontend.api.tokens.ValidityToken
 import org.jetbrains.kotlin.idea.frontend.api.components.KtSymbolContainingDeclarationProvider
 import org.jetbrains.kotlin.idea.frontend.api.fir.KtFirAnalysisSession
 import org.jetbrains.kotlin.idea.frontend.api.fir.symbols.KtFirSymbol
-import org.jetbrains.kotlin.idea.frontend.api.fir.utils.firRef
 import org.jetbrains.kotlin.idea.frontend.api.symbols.*
 import org.jetbrains.kotlin.idea.frontend.api.symbols.markers.KtSymbolKind
 import org.jetbrains.kotlin.idea.frontend.api.symbols.markers.KtSymbolWithKind
@@ -43,7 +42,7 @@ internal class KtFirSymbolContainingDeclarationProvider(
                 getContainingDeclarationForLibrarySymbol(symbol)
             KtSymbolOrigin.PROPERTY_BACKING_FIELD -> getContainingDeclarationForBackingFieldSymbol(symbol)
             KtSymbolOrigin.INTERSECTION_OVERRIDE -> TODO()
-            KtSymbolOrigin.SAM_CONSTRUCTOR -> TODO()
+            KtSymbolOrigin.SAM_CONSTRUCTOR -> null
             KtSymbolOrigin.DELEGATED -> TODO()
         }
     }
@@ -121,4 +120,4 @@ internal class KtFirSymbolContainingDeclarationProvider(
         val containingClass = containingClassId.getCorrespondingToplevelClassOrObjectSymbol()
         return containingClass ?: error("Class with id $containingClassId should exists")
     }
-}
+}

idea/idea-frontend-fir/src/org/jetbrains/kotlin/idea/frontend/api/fir/symbols/KtFirFunctionSymbol.kt

@@ -29,9 +29,7 @@ import org.jetbrains.kotlin.idea.frontend.api.symbols.KtValueParameterSymbol
 import org.jetbrains.kotlin.idea.frontend.api.symbols.markers.KtAnnotationCall
 import org.jetbrains.kotlin.idea.frontend.api.symbols.markers.KtSymbolKind
 import org.jetbrains.kotlin.idea.frontend.api.symbols.markers.KtTypeAndAnnotations
-import org.jetbrains.kotlin.idea.frontend.api.symbols.pointers.CanNotCreateSymbolPointerForLocalLibraryDeclarationException
+import org.jetbrains.kotlin.idea.frontend.api.symbols.pointers.*
-import org.jetbrains.kotlin.idea.frontend.api.symbols.pointers.KtPsiBasedSymbolPointer
-import org.jetbrains.kotlin.idea.frontend.api.symbols.pointers.KtSymbolPointer
 import org.jetbrains.kotlin.idea.frontend.api.tokens.ValidityToken
 import org.jetbrains.kotlin.idea.frontend.api.types.KtType
 import org.jetbrains.kotlin.name.CallableId
@@ -118,6 +116,7 @@ internal class KtFirFunctionSymbol(
             KtSymbolKind.LOCAL -> throw CanNotCreateSymbolPointerForLocalLibraryDeclarationException(
                 callableIdIfNonLocal?.toString() ?: name.asString()
             )
+            KtSymbolKind.SAM_CONSTRUCTOR -> throw WrongSymbolForSamConstructor(this::class.java.simpleName)
         }
     }
 

idea/idea-frontend-fir/src/org/jetbrains/kotlin/idea/frontend/api/fir/symbols/KtFirKotlinPropertySymbol.kt

@@ -32,9 +32,7 @@ import org.jetbrains.kotlin.idea.frontend.api.symbols.markers.KtAnnotationCall
 import org.jetbrains.kotlin.idea.frontend.api.symbols.markers.KtConstantValue
 import org.jetbrains.kotlin.idea.frontend.api.symbols.markers.KtSymbolKind
 import org.jetbrains.kotlin.idea.frontend.api.symbols.markers.KtTypeAndAnnotations
-import org.jetbrains.kotlin.idea.frontend.api.symbols.pointers.CanNotCreateSymbolPointerForLocalLibraryDeclarationException
+import org.jetbrains.kotlin.idea.frontend.api.symbols.pointers.*
-import org.jetbrains.kotlin.idea.frontend.api.symbols.pointers.KtPsiBasedSymbolPointer
-import org.jetbrains.kotlin.idea.frontend.api.symbols.pointers.KtSymbolPointer
 import org.jetbrains.kotlin.idea.frontend.api.tokens.ValidityToken
 import org.jetbrains.kotlin.idea.frontend.api.types.KtType
 import org.jetbrains.kotlin.name.CallableId
@@ -127,6 +125,7 @@ internal class KtFirKotlinPropertySymbol(
             }
             KtSymbolKind.ACCESSOR -> TODO("Creating symbol for accessors is not supported yet")
             KtSymbolKind.LOCAL -> throw CanNotCreateSymbolPointerForLocalLibraryDeclarationException(name.asString())
+            KtSymbolKind.SAM_CONSTRUCTOR -> throw WrongSymbolForSamConstructor(this::class.java.simpleName)
         }
     }
 

idea/idea-frontend-fir/src/org/jetbrains/kotlin/idea/frontend/api/fir/symbols/KtFirSamConstructorSymbol.kt

@@ -0,0 +1,63 @@
+/*
+ * Copyright 2010-2021 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
+ */
+
+package org.jetbrains.kotlin.idea.frontend.api.fir.symbols
+
+import com.intellij.psi.PsiElement
+import org.jetbrains.kotlin.fir.declarations.FirResolvePhase
+import org.jetbrains.kotlin.fir.declarations.FirSimpleFunction
+import org.jetbrains.kotlin.fir.resolve.getHasStableParameterNames
+import org.jetbrains.kotlin.idea.fir.findPsi
+import org.jetbrains.kotlin.idea.fir.low.level.api.api.FirModuleResolveState
+import org.jetbrains.kotlin.idea.frontend.api.fir.KtSymbolByFirBuilder
+import org.jetbrains.kotlin.idea.frontend.api.fir.symbols.pointers.KtFirSamConstructorSymbolPointer
+import org.jetbrains.kotlin.idea.frontend.api.fir.utils.cached
+import org.jetbrains.kotlin.idea.frontend.api.fir.utils.firRef
+import org.jetbrains.kotlin.idea.frontend.api.fir.utils.weakRef
+import org.jetbrains.kotlin.idea.frontend.api.symbols.KtSamConstructorSymbol
+import org.jetbrains.kotlin.idea.frontend.api.symbols.KtValueParameterSymbol
+import org.jetbrains.kotlin.idea.frontend.api.symbols.markers.KtTypeAndAnnotations
+import org.jetbrains.kotlin.idea.frontend.api.symbols.pointers.KtSymbolPointer
+import org.jetbrains.kotlin.idea.frontend.api.tokens.ValidityToken
+import org.jetbrains.kotlin.name.CallableId
+import org.jetbrains.kotlin.name.ClassId
+import org.jetbrains.kotlin.name.Name
+
+internal class KtFirSamConstructorSymbol(
+    fir: FirSimpleFunction,
+    resolveState: FirModuleResolveState,
+    override val token: ValidityToken,
+    _builder: KtSymbolByFirBuilder
+) : KtSamConstructorSymbol(), KtFirSymbol<FirSimpleFunction> {
+    private val builder by weakRef(_builder)
+    override val firRef = firRef(fir, resolveState)
+    override val psi: PsiElement? by firRef.withFirAndCache { fir -> fir.findPsi(fir.moduleData.session) }
+    override val name: Name get() = firRef.withFir { it.name }
+    override val annotatedType: KtTypeAndAnnotations by cached {
+        firRef.returnTypeAndAnnotations(FirResolvePhase.IMPLICIT_TYPES_BODY_RESOLVE, builder)
+    }
+
+    override val valueParameters: List<KtValueParameterSymbol> by firRef.withFirAndCache { fir ->
+        fir.valueParameters.map { valueParameter ->
+            builder.variableLikeBuilder.buildValueParameterSymbol(valueParameter)
+        }
+    }
+
+    override val hasStableParameterNames: Boolean = firRef.withFir { it.getHasStableParameterNames(it.moduleData.session) }
+
+    override val isExtension: Boolean get() = firRef.withFir { it.receiverTypeRef != null }
+    override val receiverType: KtTypeAndAnnotations? by cached {
+        firRef.receiverTypeAndAnnotations(builder)
+    }
+
+    override val callableIdIfNonLocal: CallableId? get() = getCallableIdIfNonLocal()
+
+    override fun createPointer(): KtSymbolPointer<KtSamConstructorSymbol> {
+        return firRef.withFir { fir ->
+            val callableId = fir.symbol.callableId
+            KtFirSamConstructorSymbolPointer(ClassId(callableId.packageName, callableId.callableName))
+        }
+    }
+}

idea/idea-frontend-fir/src/org/jetbrains/kotlin/idea/frontend/api/fir/symbols/KtFirSymbolProvider.kt

@@ -47,7 +47,13 @@ internal class KtFirSymbolProvider(
     override fun getFunctionLikeSymbol(psi: KtNamedFunction): KtFunctionLikeSymbol = withValidityAssertion {
         psi.withFirDeclarationOfType<FirFunction, KtFunctionLikeSymbol>(resolveState) { fir ->
             when (fir) {
-                is FirSimpleFunction -> firSymbolBuilder.functionLikeBuilder.buildFunctionSymbol(fir)
+                is FirSimpleFunction -> {
+                    if (fir.origin == FirDeclarationOrigin.SamConstructor) {
+                        firSymbolBuilder.functionLikeBuilder.buildSamConstructorSymbol(fir)
+                    } else {
+                        firSymbolBuilder.functionLikeBuilder.buildFunctionSymbol(fir)
+                    }
+                }
                 is FirAnonymousFunction -> firSymbolBuilder.functionLikeBuilder.buildAnonymousFunctionSymbol(fir)
                 else -> error("Unexpected ${fir.renderWithType()}")
             }

idea/idea-frontend-fir/src/org/jetbrains/kotlin/idea/frontend/api/fir/symbols/pointers/KtFirMemberSymbolPointer.kt

@@ -8,7 +8,6 @@ package org.jetbrains.kotlin.idea.frontend.api.fir.symbols.pointers
 import org.jetbrains.kotlin.fir.FirSession
 import org.jetbrains.kotlin.fir.declarations.FirRegularClass
 import org.jetbrains.kotlin.fir.resolve.ScopeSession
-import org.jetbrains.kotlin.fir.resolve.symbolProvider
 import org.jetbrains.kotlin.fir.scopes.FirScope
 import org.jetbrains.kotlin.fir.scopes.unsubstitutedScope
 import org.jetbrains.kotlin.idea.frontend.api.KtAnalysisSession
@@ -37,7 +36,3 @@ internal abstract class KtFirMemberSymbolPointer<S : KtSymbol>(
         firSession: FirSession
     ): S?
 }
-
-private fun KtFirAnalysisSession.getClassLikeSymbol(classId: ClassId) =
-    firResolveState.rootModuleSession.symbolProvider.getClassLikeSymbolByFqName(classId)?.fir
-

idea/idea-frontend-fir/src/org/jetbrains/kotlin/idea/frontend/api/fir/symbols/pointers/KtFirSamConstructorSymbolPointer.kt

@@ -0,0 +1,26 @@
+/*
+ * Copyright 2010-2021 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
+ */
+
+package org.jetbrains.kotlin.idea.frontend.api.fir.symbols.pointers
+
+import org.jetbrains.kotlin.fir.declarations.FirRegularClass
+import org.jetbrains.kotlin.idea.frontend.api.KtAnalysisSession
+import org.jetbrains.kotlin.idea.frontend.api.fir.KtFirAnalysisSession
+import org.jetbrains.kotlin.idea.frontend.api.symbols.KtSamConstructorSymbol
+import org.jetbrains.kotlin.idea.frontend.api.symbols.pointers.KtSymbolPointer
+import org.jetbrains.kotlin.name.ClassId
+
+internal class KtFirSamConstructorSymbolPointer(
+    private val ownerClassId: ClassId,
+) : KtSymbolPointer<KtSamConstructorSymbol>() {
+    override fun restoreSymbol(analysisSession: KtAnalysisSession): KtSamConstructorSymbol? {
+        require(analysisSession is KtFirAnalysisSession)
+        val owner = analysisSession.getClassLikeSymbol(ownerClassId) as? FirRegularClass ?: return null
+        val classSymbol = analysisSession.firSymbolBuilder.classifierBuilder.buildClassLikeSymbol(owner)
+        with(analysisSession) {
+            return classSymbol.getSamConstructor()
+        }
+    }
+}

idea/idea-frontend-fir/src/org/jetbrains/kotlin/idea/frontend/api/fir/symbols/pointers/pointerUtils.kt

@@ -9,11 +9,14 @@ import org.jetbrains.kotlin.fir.FirRenderer
 import org.jetbrains.kotlin.fir.FirSession
 import org.jetbrains.kotlin.fir.declarations.FirDeclaration
 import org.jetbrains.kotlin.fir.renderWithType
+import org.jetbrains.kotlin.fir.resolve.symbolProvider
 import org.jetbrains.kotlin.fir.scopes.FirScope
 import org.jetbrains.kotlin.fir.symbols.FirBasedSymbol
 import org.jetbrains.kotlin.fir.symbols.impl.FirCallableSymbol
 import org.jetbrains.kotlin.idea.fir.low.level.api.ideSessionComponents
+import org.jetbrains.kotlin.idea.frontend.api.fir.KtFirAnalysisSession
 import org.jetbrains.kotlin.ir.util.IdSignature
+import org.jetbrains.kotlin.name.ClassId
 
 internal inline fun <reified D : FirDeclaration> FirScope.findDeclarationWithSignature(
     signature: IdSignature,
@@ -50,3 +53,6 @@ internal fun FirDeclaration.createSignature(): IdSignature {
     return signatureComposer.composeSignature(this)
         ?: error("Could not compose signature for ${this.renderWithType(FirRenderer.RenderMode.WithResolvePhases)}, looks like it is private or local")
 }
+
+internal fun KtFirAnalysisSession.getClassLikeSymbol(classId: ClassId) =
+    firResolveState.rootModuleSession.symbolProvider.getClassLikeSymbolByFqName(classId)?.fir

idea/idea-frontend-fir/testData/symbols/symbolByReference/samConstructor.kt

@@ -0,0 +1 @@
+val greeter = <caret>Runnable { println("Howdy") }

idea/idea-frontend-fir/testData/symbols/symbolByReference/samConstructor.txt

@@ -0,0 +1,13 @@
+KtFirSamConstructorSymbol:
+  annotatedType: [] java/lang/Runnable
+  callableIdIfNonLocal: java/lang/Runnable
+  hasStableParameterNames: true
+  isExtension: false
+  name: Runnable
+  origin: SAM_CONSTRUCTOR
+  receiverType: null
+  symbolKind: SAM_CONSTRUCTOR
+  valueParameters: [
+    KtFirValueParameterSymbol(block)
+  ]
+  deprecationStatus: null

idea/idea-frontend-fir/tests/org/jetbrains/kotlin/idea/fir/frontend/api/symbols/AbstractSymbolTest.kt

@@ -68,7 +68,7 @@ abstract class AbstractSymbolTest : AbstractHLApiSingleFileTest() {
         val restored = analyseOnPooledThreadInReadAction(ktFile) {
             pointersWithRendered.map { (pointer, expectedRender) ->
                 val restored = pointer!!.restoreSymbol()
-                    ?: error("Symbol $expectedRender was not not restored")
+                    ?: error("Symbol $expectedRender was not restored")
                 with(DebugSymbolRenderer) { renderExtra(restored) }
             }
         }
@@ -84,9 +84,9 @@ abstract class AbstractSymbolTest : AbstractHLApiSingleFileTest() {
 
 private object SymbolTestDirectives : SimpleDirectivesContainer() {
     val DO_NOT_CHECK_SYMBOL_RESTORE by directive(
-        description = "Symbol restoring for some symbols in current test is not yet supported yet",
+        description = "Symbol restoring for some symbols in current test is not supported yet",
         applicability = DirectiveApplicability.Global
     )
 }
 
-private data class PointerWithRenderedSymbol(val pointer: KtSymbolPointer<*>?, val rendered: String)
+private data class PointerWithRenderedSymbol(val pointer: KtSymbolPointer<*>?, val rendered: String)

idea/idea-frontend-fir/tests/org/jetbrains/kotlin/idea/fir/frontend/api/symbols/SymbolByReferenceTestGenerated.java

@@ -35,4 +35,10 @@ public class SymbolByReferenceTestGenerated extends AbstractSymbolByReferenceTes
     public void testConstructorViaTypeAlias() throws Exception {
         runTest("idea/idea-frontend-fir/testData/symbols/symbolByReference/constructorViaTypeAlias.kt");
     }
+
+    @Test
+    @TestMetadata("samConstructor.kt")
+    public void testSamConstructor() throws Exception {
+        runTest("idea/idea-frontend-fir/testData/symbols/symbolByReference/samConstructor.kt");
+    }
 }