FIR2IR: use FirSamResolverImpl to get function type for possible SAM type

compiler/fir/fir2ir/src/org/jetbrains/kotlin/fir/backend/generators/CallAndReferenceGenerator.kt

@@ -17,13 +17,12 @@ import org.jetbrains.kotlin.fir.references.FirResolvedNamedReference
 import org.jetbrains.kotlin.fir.references.FirSuperReference
 import org.jetbrains.kotlin.fir.references.impl.FirReferencePlaceholderForResolvedAnnotations
 import org.jetbrains.kotlin.fir.render
+import org.jetbrains.kotlin.fir.resolve.FirSamResolverImpl
 import org.jetbrains.kotlin.fir.resolve.calls.getExpectedTypeForSAMConversion
 import org.jetbrains.kotlin.fir.resolve.calls.isFunctional
 import org.jetbrains.kotlin.fir.resolve.fullyExpandedType
 import org.jetbrains.kotlin.fir.resolve.inference.isBuiltinFunctionalType
 import org.jetbrains.kotlin.fir.resolve.inference.isKMutableProperty
-import org.jetbrains.kotlin.fir.resolve.resolveFunctionTypeIfSamInterface
-import org.jetbrains.kotlin.fir.resolve.toFirRegularClass
 import org.jetbrains.kotlin.fir.resolve.toSymbol
 import org.jetbrains.kotlin.fir.scopes.unsubstitutedScope
 import org.jetbrains.kotlin.fir.symbols.impl.*
@@ -48,6 +47,7 @@ class CallAndReferenceGenerator(
 
     private val approximator = object : AbstractTypeApproximator(session.typeContext) {}
     private val adapterGenerator = AdapterGenerator(components, conversionScope)
+    private val samResolver = FirSamResolverImpl(session, scopeSession)
 
     private fun FirTypeRef.toIrType(): IrType = with(typeConverter) { toIrType() }
 
@@ -621,10 +621,7 @@ class CallAndReferenceGenerator(
             return false
         }
         // On the other hand, the actual type should be either a functional type or a subtype of a class that has a contributed `invoke`.
-        val lookupTag = parameter.returnTypeRef.coneTypeSafe<ConeClassLikeType>()?.lookupTag
+        val expectedFunctionType = samResolver.getFunctionTypeForPossibleSamType(parameter.returnTypeRef.coneType)
-        val firRegularClass = lookupTag?.toFirRegularClass(session)
-        // TODO: cache SAM interface to resolved function type, as [SamResolution] does?
-        val expectedFunctionType = firRegularClass?.resolveFunctionTypeIfSamInterface(session, scopeSession)
         return argument.isFunctional(session, scopeSession, expectedFunctionType)
     }
 

compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/SamResolution.kt

@@ -45,7 +45,7 @@ val SAM_PARAMETER_NAME = Name.identifier("block")
 class FirSamResolverImpl(
     private val firSession: FirSession,
     private val scopeSession: ScopeSession,
-    private val outerClassManager: FirOuterClassManager,
+    private val outerClassManager: FirOuterClassManager? = null,
 ) : FirSamResolver() {
 
     private val resolvedFunctionType: MutableMap<FirRegularClass, Any> = mutableMapOf()
@@ -206,13 +206,17 @@ class FirSamResolverImpl(
 
             resolvePhase = FirResolvePhase.BODY_RESOLVE
         }.apply {
-            containingClassAttr = outerClassManager.outerClass(firRegularClass.symbol)?.toLookupTag()
+            containingClassAttr = outerClassManager?.outerClass(firRegularClass.symbol)?.toLookupTag()
         }
     }
 
     private fun resolveFunctionTypeIfSamInterface(firRegularClass: FirRegularClass): ConeLookupTagBasedType? {
         return resolvedFunctionType.getOrPut(firRegularClass) {
-            firRegularClass.resolveFunctionTypeIfSamInterface(firSession, scopeSession) ?: NULL_STUB
+            if (!firRegularClass.status.isFun) return@getOrPut NULL_STUB
+            val abstractMethod = firRegularClass.getSingleAbstractMethodOrNull(firSession, scopeSession) ?: return@getOrPut NULL_STUB
+            // TODO: val shouldConvertFirstParameterToDescriptor = samWithReceiverResolvers.any { it.shouldConvertFirstSamParameterToReceiver(abstractMethod) }
+
+            abstractMethod.getFunctionTypeForAbstractMethod()
         } as? ConeLookupTagBasedType
     }
 
@@ -222,17 +226,6 @@ class FirSamResolverImpl(
     }
 }
 
-fun FirRegularClass.resolveFunctionTypeIfSamInterface(
-    session: FirSession,
-    scopeSession: ScopeSession
-): ConeLookupTagBasedType? {
-    if (!this.status.isFun) return null
-    val abstractMethod = getSingleAbstractMethodOrNull(session, scopeSession) ?: return null
-    // TODO: val shouldConvertFirstParameterToDescriptor = samWithReceiverResolvers.any { it.shouldConvertFirstSamParameterToReceiver(abstractMethod) }
-
-    return abstractMethod.getFunctionTypeForAbstractMethod()
-}
-
 private fun FirRegularClass.getSingleAbstractMethodOrNull(
     session: FirSession,
     scopeSession: ScopeSession,