KT-34509 Properly unwrap callable reference descriptor

NB there's a problem with callable references to SAM constructors,
see also KT-16789

compiler/fir/fir2ir/tests/org/jetbrains/kotlin/fir/Fir2IrTextTestGenerated.java

@@ -1212,6 +1212,11 @@ public class Fir2IrTextTestGenerated extends AbstractFir2IrTextTest {
             runTest("compiler/testData/ir/irText/expressions/tryCatchWithImplicitCast.kt");
         }
 
+        @TestMetadata("typeAliasConstructorReference.kt")
+        public void testTypeAliasConstructorReference() throws Exception {
+            runTest("compiler/testData/ir/irText/expressions/typeAliasConstructorReference.kt");
+        }
+
         @TestMetadata("typeArguments.kt")
         public void testTypeArguments() throws Exception {
             runTest("compiler/testData/ir/irText/expressions/typeArguments.kt");

compiler/ir/ir.psi2ir/src/org/jetbrains/kotlin/psi2ir/generators/ReflectionReferencesGenerator.kt

@@ -29,7 +29,6 @@ import org.jetbrains.kotlin.psi.KtElement
 import org.jetbrains.kotlin.psi.psiUtil.endOffset
 import org.jetbrains.kotlin.psi.psiUtil.startOffsetSkippingComments
 import org.jetbrains.kotlin.resolve.BindingContext
-import org.jetbrains.kotlin.resolve.ImportedFromObjectCallableDescriptor
 import org.jetbrains.kotlin.types.KotlinType
 import org.jetbrains.kotlin.types.expressions.DoubleColonLHS
 
@@ -58,22 +57,21 @@ class ReflectionReferencesGenerator(statementGenerator: StatementGenerator) : St
 
     fun generateCallableReference(ktCallableReference: KtCallableReferenceExpression): IrExpression {
         val resolvedCall = getResolvedCall(ktCallableReference.callableReference)!!
+        val resolvedDescriptor = resolvedCall.resultingDescriptor
 
-        val resultingDescriptor = resolvedCall.resultingDescriptor
-        val descriptorImportedFromObject = resultingDescriptor as? ImportedFromObjectCallableDescriptor<*>
-        val referencedDescriptor = descriptorImportedFromObject?.callableFromObject ?: resultingDescriptor
+        val callBuilder = unwrapCallableDescriptorAndTypeArguments(resolvedCall, context.extensions.samConversion)
 
         return statementGenerator.generateCallReceiver(
             ktCallableReference,
-            resultingDescriptor,
+            resolvedDescriptor,
             resolvedCall.dispatchReceiver, resolvedCall.extensionReceiver,
             isSafe = false
         ).call { dispatchReceiverValue, extensionReceiverValue ->
             generateCallableReference(
                 ktCallableReference,
                 getInferredTypeWithImplicitCastsOrFail(ktCallableReference),
-                referencedDescriptor,
-                resolvedCall.typeArguments
+                callBuilder.descriptor,
+                callBuilder.typeArguments
             ).also { irCallableReference ->
                 irCallableReference.dispatchReceiver = dispatchReceiverValue?.loadIfExists()
                 irCallableReference.extensionReceiver = extensionReceiverValue?.loadIfExists()

compiler/testData/ir/irText/expressions/typeAliasConstructorReference.fir.txt

@@ -0,0 +1,78 @@
+FILE fqName:<root> fileName:/typeAliasConstructorReference.kt
+  CLASS CLASS name:C modality:FINAL visibility:public superTypes:[kotlin.Any]
+    $this: VALUE_PARAMETER INSTANCE_RECEIVER name:<this> type:<root>.C
+    CONSTRUCTOR visibility:public <> (x:kotlin.Int) returnType:<root>.C [primary]
+      VALUE_PARAMETER name:x index:0 type:kotlin.Int
+      BLOCK_BODY
+        DELEGATING_CONSTRUCTOR_CALL 'public constructor <init> () [primary] declared in kotlin.Any'
+        INSTANCE_INITIALIZER_CALL classDescriptor='CLASS CLASS name:C modality:FINAL visibility:public superTypes:[kotlin.Any]'
+    FUN FAKE_OVERRIDE name:equals visibility:public modality:OPEN <> ($this:kotlin.Any, other:kotlin.Any?) returnType:kotlin.Boolean
+      overridden:
+        public open fun equals (other: kotlin.Any?): kotlin.Boolean declared in kotlin.Any
+      $this: VALUE_PARAMETER name:<this> type:kotlin.Any
+      VALUE_PARAMETER name:other index:0 type:kotlin.Any?
+    FUN FAKE_OVERRIDE name:hashCode visibility:public modality:OPEN <> ($this:kotlin.Any) returnType:kotlin.Int
+      overridden:
+        public open fun hashCode (): kotlin.Int declared in kotlin.Any
+      $this: VALUE_PARAMETER name:<this> type:kotlin.Any
+    FUN FAKE_OVERRIDE name:toString visibility:public modality:OPEN <> ($this:kotlin.Any) returnType:kotlin.String
+      overridden:
+        public open fun toString (): kotlin.String declared in kotlin.Any
+      $this: VALUE_PARAMETER name:<this> type:kotlin.Any
+  CLASS OBJECT name:Host modality:FINAL visibility:public superTypes:[kotlin.Any]
+    $this: VALUE_PARAMETER INSTANCE_RECEIVER name:<this> type:<root>.Host
+    CONSTRUCTOR visibility:private <> () returnType:<root>.Host [primary]
+      BLOCK_BODY
+        DELEGATING_CONSTRUCTOR_CALL 'public constructor <init> () [primary] declared in kotlin.Any'
+        INSTANCE_INITIALIZER_CALL classDescriptor='CLASS OBJECT name:Host modality:FINAL visibility:public superTypes:[kotlin.Any]'
+    CLASS CLASS name:Nested modality:FINAL visibility:public superTypes:[kotlin.Any]
+      $this: VALUE_PARAMETER INSTANCE_RECEIVER name:<this> type:<root>.Host.Nested
+      CONSTRUCTOR visibility:public <> (x:kotlin.Int) returnType:<root>.Host.Nested [primary]
+        VALUE_PARAMETER name:x index:0 type:kotlin.Int
+        BLOCK_BODY
+          DELEGATING_CONSTRUCTOR_CALL 'public constructor <init> () [primary] declared in kotlin.Any'
+          INSTANCE_INITIALIZER_CALL classDescriptor='CLASS CLASS name:Nested modality:FINAL visibility:public superTypes:[kotlin.Any]'
+      FUN FAKE_OVERRIDE name:equals visibility:public modality:OPEN <> ($this:kotlin.Any, other:kotlin.Any?) returnType:kotlin.Boolean
+        overridden:
+          public open fun equals (other: kotlin.Any?): kotlin.Boolean declared in kotlin.Any
+        $this: VALUE_PARAMETER name:<this> type:kotlin.Any
+        VALUE_PARAMETER name:other index:0 type:kotlin.Any?
+      FUN FAKE_OVERRIDE name:hashCode visibility:public modality:OPEN <> ($this:kotlin.Any) returnType:kotlin.Int
+        overridden:
+          public open fun hashCode (): kotlin.Int declared in kotlin.Any
+        $this: VALUE_PARAMETER name:<this> type:kotlin.Any
+      FUN FAKE_OVERRIDE name:toString visibility:public modality:OPEN <> ($this:kotlin.Any) returnType:kotlin.String
+        overridden:
+          public open fun toString (): kotlin.String declared in kotlin.Any
+        $this: VALUE_PARAMETER name:<this> type:kotlin.Any
+    FUN FAKE_OVERRIDE name:equals visibility:public modality:OPEN <> ($this:kotlin.Any, other:kotlin.Any?) returnType:kotlin.Boolean
+      overridden:
+        public open fun equals (other: kotlin.Any?): kotlin.Boolean declared in kotlin.Any
+      $this: VALUE_PARAMETER name:<this> type:kotlin.Any
+      VALUE_PARAMETER name:other index:0 type:kotlin.Any?
+    FUN FAKE_OVERRIDE name:hashCode visibility:public modality:OPEN <> ($this:kotlin.Any) returnType:kotlin.Int
+      overridden:
+        public open fun hashCode (): kotlin.Int declared in kotlin.Any
+      $this: VALUE_PARAMETER name:<this> type:kotlin.Any
+    FUN FAKE_OVERRIDE name:toString visibility:public modality:OPEN <> ($this:kotlin.Any) returnType:kotlin.String
+      overridden:
+        public open fun toString (): kotlin.String declared in kotlin.Any
+      $this: VALUE_PARAMETER name:<this> type:kotlin.Any
+  PROPERTY name:test1 visibility:public modality:FINAL [val]
+    FIELD PROPERTY_BACKING_FIELD name:test1 type:kotlin.Function1<kotlin.Int, <root>.C> visibility:private [final,static]
+      EXPRESSION_BODY
+        GET_OBJECT 'CLASS CLASS name:C modality:FINAL visibility:public superTypes:[kotlin.Any]' type=kotlin.Unit
+    FUN DEFAULT_PROPERTY_ACCESSOR name:<get-test1> visibility:public modality:FINAL <> () returnType:kotlin.Function1<kotlin.Int, <root>.C>
+      correspondingProperty: PROPERTY name:test1 visibility:public modality:FINAL [val]
+      BLOCK_BODY
+        RETURN type=kotlin.Nothing from='public final fun <get-test1> (): kotlin.Function1<kotlin.Int, <root>.C> declared in <root>'
+          GET_FIELD 'FIELD PROPERTY_BACKING_FIELD name:test1 type:kotlin.Function1<kotlin.Int, <root>.C> visibility:private [final,static]' type=kotlin.Function1<kotlin.Int, <root>.C> origin=null
+  PROPERTY name:test2 visibility:public modality:FINAL [val]
+    FIELD PROPERTY_BACKING_FIELD name:test2 type:kotlin.Function1<kotlin.Int, <root>.Host.Nested> visibility:private [final,static]
+      EXPRESSION_BODY
+        GET_OBJECT 'CLASS CLASS name:Nested modality:FINAL visibility:public superTypes:[kotlin.Any]' type=kotlin.Unit
+    FUN DEFAULT_PROPERTY_ACCESSOR name:<get-test2> visibility:public modality:FINAL <> () returnType:kotlin.Function1<kotlin.Int, <root>.Host.Nested>
+      correspondingProperty: PROPERTY name:test2 visibility:public modality:FINAL [val]
+      BLOCK_BODY
+        RETURN type=kotlin.Nothing from='public final fun <get-test2> (): kotlin.Function1<kotlin.Int, <root>.Host.Nested> declared in <root>'
+          GET_FIELD 'FIELD PROPERTY_BACKING_FIELD name:test2 type:kotlin.Function1<kotlin.Int, <root>.Host.Nested> visibility:private [final,static]' type=kotlin.Function1<kotlin.Int, <root>.Host.Nested> origin=null

compiler/testData/ir/irText/expressions/typeAliasConstructorReference.kt

@@ -0,0 +1,14 @@
+import Host.Nested
+
+class C(x: Int)
+
+typealias CA = C
+
+object Host {
+    class Nested(x: Int)
+}
+
+typealias NA = Nested
+
+val test1: (Int) -> CA = ::CA
+val test2: (Int) -> NA = ::NA

compiler/testData/ir/irText/expressions/typeAliasConstructorReference.txt

@@ -0,0 +1,80 @@
+FILE fqName:<root> fileName:/typeAliasConstructorReference.kt
+  CLASS CLASS name:C modality:FINAL visibility:public superTypes:[kotlin.Any]
+    $this: VALUE_PARAMETER INSTANCE_RECEIVER name:<this> type:<root>.C
+    CONSTRUCTOR visibility:public <> (x:kotlin.Int) returnType:<root>.C [primary]
+      VALUE_PARAMETER name:x index:0 type:kotlin.Int
+      BLOCK_BODY
+        DELEGATING_CONSTRUCTOR_CALL 'public constructor <init> () [primary] declared in kotlin.Any'
+        INSTANCE_INITIALIZER_CALL classDescriptor='CLASS CLASS name:C modality:FINAL visibility:public superTypes:[kotlin.Any]'
+    FUN FAKE_OVERRIDE name:equals visibility:public modality:OPEN <> ($this:kotlin.Any, other:kotlin.Any?) returnType:kotlin.Boolean
+      overridden:
+        public open fun equals (other: kotlin.Any?): kotlin.Boolean declared in kotlin.Any
+      $this: VALUE_PARAMETER name:<this> type:kotlin.Any
+      VALUE_PARAMETER name:other index:0 type:kotlin.Any?
+    FUN FAKE_OVERRIDE name:hashCode visibility:public modality:OPEN <> ($this:kotlin.Any) returnType:kotlin.Int
+      overridden:
+        public open fun hashCode (): kotlin.Int declared in kotlin.Any
+      $this: VALUE_PARAMETER name:<this> type:kotlin.Any
+    FUN FAKE_OVERRIDE name:toString visibility:public modality:OPEN <> ($this:kotlin.Any) returnType:kotlin.String
+      overridden:
+        public open fun toString (): kotlin.String declared in kotlin.Any
+      $this: VALUE_PARAMETER name:<this> type:kotlin.Any
+  TYPEALIAS name:CA visibility:public expandedType:<root>.C
+  CLASS OBJECT name:Host modality:FINAL visibility:public superTypes:[kotlin.Any]
+    $this: VALUE_PARAMETER INSTANCE_RECEIVER name:<this> type:<root>.Host
+    CONSTRUCTOR visibility:private <> () returnType:<root>.Host [primary]
+      BLOCK_BODY
+        DELEGATING_CONSTRUCTOR_CALL 'public constructor <init> () [primary] declared in kotlin.Any'
+        INSTANCE_INITIALIZER_CALL classDescriptor='CLASS OBJECT name:Host modality:FINAL visibility:public superTypes:[kotlin.Any]'
+    CLASS CLASS name:Nested modality:FINAL visibility:public superTypes:[kotlin.Any]
+      $this: VALUE_PARAMETER INSTANCE_RECEIVER name:<this> type:<root>.Host.Nested
+      CONSTRUCTOR visibility:public <> (x:kotlin.Int) returnType:<root>.Host.Nested [primary]
+        VALUE_PARAMETER name:x index:0 type:kotlin.Int
+        BLOCK_BODY
+          DELEGATING_CONSTRUCTOR_CALL 'public constructor <init> () [primary] declared in kotlin.Any'
+          INSTANCE_INITIALIZER_CALL classDescriptor='CLASS CLASS name:Nested modality:FINAL visibility:public superTypes:[kotlin.Any]'
+      FUN FAKE_OVERRIDE name:equals visibility:public modality:OPEN <> ($this:kotlin.Any, other:kotlin.Any?) returnType:kotlin.Boolean
+        overridden:
+          public open fun equals (other: kotlin.Any?): kotlin.Boolean declared in kotlin.Any
+        $this: VALUE_PARAMETER name:<this> type:kotlin.Any
+        VALUE_PARAMETER name:other index:0 type:kotlin.Any?
+      FUN FAKE_OVERRIDE name:hashCode visibility:public modality:OPEN <> ($this:kotlin.Any) returnType:kotlin.Int
+        overridden:
+          public open fun hashCode (): kotlin.Int declared in kotlin.Any
+        $this: VALUE_PARAMETER name:<this> type:kotlin.Any
+      FUN FAKE_OVERRIDE name:toString visibility:public modality:OPEN <> ($this:kotlin.Any) returnType:kotlin.String
+        overridden:
+          public open fun toString (): kotlin.String declared in kotlin.Any
+        $this: VALUE_PARAMETER name:<this> type:kotlin.Any
+    FUN FAKE_OVERRIDE name:equals visibility:public modality:OPEN <> ($this:kotlin.Any, other:kotlin.Any?) returnType:kotlin.Boolean
+      overridden:
+        public open fun equals (other: kotlin.Any?): kotlin.Boolean declared in kotlin.Any
+      $this: VALUE_PARAMETER name:<this> type:kotlin.Any
+      VALUE_PARAMETER name:other index:0 type:kotlin.Any?
+    FUN FAKE_OVERRIDE name:hashCode visibility:public modality:OPEN <> ($this:kotlin.Any) returnType:kotlin.Int
+      overridden:
+        public open fun hashCode (): kotlin.Int declared in kotlin.Any
+      $this: VALUE_PARAMETER name:<this> type:kotlin.Any
+    FUN FAKE_OVERRIDE name:toString visibility:public modality:OPEN <> ($this:kotlin.Any) returnType:kotlin.String
+      overridden:
+        public open fun toString (): kotlin.String declared in kotlin.Any
+      $this: VALUE_PARAMETER name:<this> type:kotlin.Any
+  TYPEALIAS name:NA visibility:public expandedType:<root>.Host.Nested
+  PROPERTY name:test1 visibility:public modality:FINAL [val]
+    FIELD PROPERTY_BACKING_FIELD name:test1 type:kotlin.Function1<kotlin.Int, <root>.C{ <root>.CA }> visibility:private [final,static]
+      EXPRESSION_BODY
+        FUNCTION_REFERENCE 'public constructor <init> (x: kotlin.Int) [primary] declared in <root>.C' type=kotlin.reflect.KFunction1<@[ParameterName(name = 'x')] kotlin.Int, <root>.C{ <root>.CA }> origin=null
+    FUN DEFAULT_PROPERTY_ACCESSOR name:<get-test1> visibility:public modality:FINAL <> () returnType:kotlin.Function1<kotlin.Int, <root>.C{ <root>.CA }>
+      correspondingProperty: PROPERTY name:test1 visibility:public modality:FINAL [val]
+      BLOCK_BODY
+        RETURN type=kotlin.Nothing from='public final fun <get-test1> (): kotlin.Function1<kotlin.Int, <root>.C{ <root>.CA }> declared in <root>'
+          GET_FIELD 'FIELD PROPERTY_BACKING_FIELD name:test1 type:kotlin.Function1<kotlin.Int, <root>.C{ <root>.CA }> visibility:private [final,static]' type=kotlin.Function1<kotlin.Int, <root>.C{ <root>.CA }> origin=null
+  PROPERTY name:test2 visibility:public modality:FINAL [val]
+    FIELD PROPERTY_BACKING_FIELD name:test2 type:kotlin.Function1<kotlin.Int, <root>.Host.Nested{ <root>.NA }> visibility:private [final,static]
+      EXPRESSION_BODY
+        FUNCTION_REFERENCE 'public constructor <init> (x: kotlin.Int) [primary] declared in <root>.Host.Nested' type=kotlin.reflect.KFunction1<@[ParameterName(name = 'x')] kotlin.Int, <root>.Host.Nested{ <root>.NA }> origin=null
+    FUN DEFAULT_PROPERTY_ACCESSOR name:<get-test2> visibility:public modality:FINAL <> () returnType:kotlin.Function1<kotlin.Int, <root>.Host.Nested{ <root>.NA }>
+      correspondingProperty: PROPERTY name:test2 visibility:public modality:FINAL [val]
+      BLOCK_BODY
+        RETURN type=kotlin.Nothing from='public final fun <get-test2> (): kotlin.Function1<kotlin.Int, <root>.Host.Nested{ <root>.NA }> declared in <root>'
+          GET_FIELD 'FIELD PROPERTY_BACKING_FIELD name:test2 type:kotlin.Function1<kotlin.Int, <root>.Host.Nested{ <root>.NA }> visibility:private [final,static]' type=kotlin.Function1<kotlin.Int, <root>.Host.Nested{ <root>.NA }> origin=null

compiler/tests/org/jetbrains/kotlin/ir/IrTextTestCaseGenerated.java

@@ -1212,6 +1212,11 @@ public class IrTextTestCaseGenerated extends AbstractIrTextTestCase {
             runTest("compiler/testData/ir/irText/expressions/tryCatchWithImplicitCast.kt");
         }
 
+        @TestMetadata("typeAliasConstructorReference.kt")
+        public void testTypeAliasConstructorReference() throws Exception {
+            runTest("compiler/testData/ir/irText/expressions/typeAliasConstructorReference.kt");
+        }
+
         @TestMetadata("typeArguments.kt")
         public void testTypeArguments() throws Exception {
             runTest("compiler/testData/ir/irText/expressions/typeArguments.kt");