FIR: Support callable references for constructors

^KT-32725 In Progress

compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/calls/ConeOverloadConflictResolver.kt

@@ -61,7 +61,7 @@ class ConeOverloadConflictResolver(
         return FlatSignature(
             call,
             constructor.typeParameters.map { it.symbol },
-            call.argumentMapping!!.map {  it.value.argumentType() },
+            computeParameterTypes(call, constructor),
             //constructor.receiverTypeRef != null,
             false,
             constructor.valueParameters.any { it.isVararg },
@@ -78,15 +78,10 @@ class ConeOverloadConflictResolver(
     }
 
     private fun createFlatSignature(call: Candidate, function: FirSimpleFunction): FlatSignature<Candidate> {
-        val valueParametersTypes =
-            call.resultingTypeForCallableReference?.typeArguments?.map { it as ConeKotlinType }
-                ?: (listOfNotNull<ConeKotlinType>(function.receiverTypeRef?.coneTypeUnsafe()) +
-                        call.argumentMapping?.map { it.value.argumentType() }.orEmpty())
-
         return FlatSignature(
             call,
             function.typeParameters.map { it.symbol },
-            valueParametersTypes,
+            computeParameterTypes(call, function),
             function.receiverTypeRef != null,
             function.valueParameters.any { it.isVararg },
             function.valueParameters.count { it.defaultValue != null },
@@ -95,6 +90,15 @@ class ConeOverloadConflictResolver(
         )
     }
 
+    private fun computeParameterTypes(
+        call: Candidate,
+        function: FirFunction<*>
+    ): List<ConeKotlinType> {
+        return (call.resultingTypeForCallableReference?.typeArguments?.map { it as ConeKotlinType }
+            ?: (listOfNotNull<ConeKotlinType>(function.receiverTypeRef?.coneTypeUnsafe()) +
+                    call.argumentMapping?.map { it.value.argumentType() }.orEmpty()))
+    }
+
     private fun createFlatSignature(call: Candidate, variable: FirVariable<*>): FlatSignature<Candidate> {
         return FlatSignature(
             call,

compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/calls/ResolverParts.kt

@@ -190,7 +190,7 @@ internal object CheckCallableReferenceExpectedType : CheckerStage() {
         val returnTypeRef = candidate.bodyResolveComponents.returnTypeCalculator.tryCalculateReturnType(fir)
 
         val resultingType: ConeKotlinType = when (fir) {
-            is FirSimpleFunction -> createKFunctionType(fir, resultingReceiverType, returnTypeRef)
+            is FirFunction -> createKFunctionType(fir, resultingReceiverType, returnTypeRef)
             is FirProperty -> createKPropertyType(fir, resultingReceiverType, returnTypeRef)
             else -> ConeKotlinErrorType("Unknown callable kind: ${fir::class}")
         }.let(candidate.substitutor::substituteOrSelf)
@@ -242,7 +242,7 @@ private fun createKPropertyType(
 }
 
 private fun createKFunctionType(
-    function: FirSimpleFunction,
+    function: FirFunction<*>,
     receiverType: ConeKotlinType?,
     returnTypeRef: FirResolvedTypeRef
 ): ConeKotlinType {

compiler/fir/resolve/testData/diagnostics/callableReferences/constructors.kt

@@ -0,0 +1,10 @@
+class Klass {
+    constructor(a: Int) {}
+    constructor(a: String) {}
+}
+
+fun user(f: (Int) -> Klass) {}
+
+fun fn() {
+    user(::Klass)
+}

compiler/fir/resolve/testData/diagnostics/callableReferences/constructors.txt

@@ -0,0 +1,16 @@
+FILE: constructors.kt
+    public final class Klass : R|kotlin/Any| {
+        public constructor(a: R|kotlin/Int|): R|Klass| {
+            super<R|kotlin/Any|>()
+        }
+
+        public constructor(a: R|kotlin/String|): R|Klass| {
+            super<R|kotlin/Any|>()
+        }
+
+    }
+    public final fun user(f: R|kotlin/Function1<kotlin/Int, Klass>|): R|kotlin/Unit| {
+    }
+    public final fun fn(): R|kotlin/Unit| {
+        R|/user|(::R|/Klass.Klass|)
+    }

compiler/fir/resolve/tests/org/jetbrains/kotlin/fir/FirDiagnosticsTestGenerated.java

@@ -50,6 +50,11 @@ public class FirDiagnosticsTestGenerated extends AbstractFirDiagnosticsTest {
             runTest("compiler/fir/resolve/testData/diagnostics/callableReferences/companions.kt");
         }
 
+        @TestMetadata("constructors.kt")
+        public void testConstructors() throws Exception {
+            runTest("compiler/fir/resolve/testData/diagnostics/callableReferences/constructors.kt");
+        }
+
         @TestMetadata("differentLevels.kt")
         public void testDifferentLevels() throws Exception {
             runTest("compiler/fir/resolve/testData/diagnostics/callableReferences/differentLevels.kt");