[NI] Fix ambiguity for extension functions with exact transient receiver

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

@@ -2518,6 +2518,11 @@ public class FirDiagnosticsSmokeTestGenerated extends AbstractFirDiagnosticsSmok
                 runTest("compiler/testData/diagnostics/tests/callableReference/resolve/chooseCallableReferenceDependingOnInferredReceiver.kt");
             }
 
+            @TestMetadata("chooseMostSpecificCandidateUsingCandidateDescriptorNotReflectionType.kt")
+            public void testChooseMostSpecificCandidateUsingCandidateDescriptorNotReflectionType() throws Exception {
+                runTest("compiler/testData/diagnostics/tests/callableReference/resolve/chooseMostSpecificCandidateUsingCandidateDescriptorNotReflectionType.kt");
+            }
+
             @TestMetadata("chooseOuterCallBySingleCallableReference.kt")
             public void testChooseOuterCallBySingleCallableReference() throws Exception {
                 runTest("compiler/testData/diagnostics/tests/callableReference/resolve/chooseOuterCallBySingleCallableReference.kt");

compiler/resolution/src/org/jetbrains/kotlin/resolve/calls/results/FlatSignature.kt

@@ -16,7 +16,7 @@
 
 package org.jetbrains.kotlin.resolve.calls.results
 
-import org.jetbrains.kotlin.builtins.getAllParameterProjectionsFromCallableReflectionType
+import org.jetbrains.kotlin.builtins.getValueParameterTypesFromCallableReflectionType
 import org.jetbrains.kotlin.container.DefaultImplementation
 import org.jetbrains.kotlin.container.PlatformSpecificExtension
 import org.jetbrains.kotlin.descriptors.CallableDescriptor
@@ -24,7 +24,9 @@ import org.jetbrains.kotlin.descriptors.MemberDescriptor
 import org.jetbrains.kotlin.descriptors.ValueParameterDescriptor
 import org.jetbrains.kotlin.descriptors.synthetic.SyntheticMemberDescriptor
 import org.jetbrains.kotlin.resolve.calls.components.hasDefaultValue
-import org.jetbrains.kotlin.types.*
+import org.jetbrains.kotlin.types.AbstractTypeChecker
+import org.jetbrains.kotlin.types.KotlinType
+import org.jetbrains.kotlin.types.UnwrappedType
 import org.jetbrains.kotlin.types.model.*
 
 interface SpecificityComparisonCallbacks {
@@ -59,11 +61,18 @@ class FlatSignature<out T> constructor(
             numDefaults: Int,
             reflectionType: UnwrappedType
         ): FlatSignature<T> {
+            // Note that receiver is taking over descriptor, not reflection type
+            // This is correct as extension receiver can't have any defaults/varargs/coercions, so there is no need to use reflection type
+            // Plus, currently, receiver for reflection type is taking from *candidate*, see buildReflectionType, this candidate can
+            // have transient receiver which is not the same in its signature
+            val receiver = descriptor.extensionReceiverParameter?.type
+            val parameters = reflectionType.getValueParameterTypesFromCallableReflectionType(receiver == null).map { it.type }
+
             return FlatSignature(
                 origin,
                 descriptor.typeParameters,
-                reflectionType.getAllParameterProjectionsFromCallableReflectionType().map { it.type },
-                hasExtensionReceiver = false,
+                listOfNotNull(receiver) + parameters,
+                hasExtensionReceiver = receiver != null,
                 hasVarargs = descriptor.valueParameters.any { it.varargElementType != null },
                 numDefaults = numDefaults,
                 isExpect = descriptor is MemberDescriptor && descriptor.isExpect,

compiler/testData/diagnostics/tests/callableReference/resolve/chooseMostSpecificCandidateUsingCandidateDescriptorNotReflectionType.kt

@@ -0,0 +1,14 @@
+// !DIAGNOSTICS: -UNUSED_PARAMETER
+
+fun test() {
+    foo(String::extensionReceiver)
+    foo(::valueParameter)
+}
+
+fun CharSequence.extensionReceiver(): CharSequence = TODO()
+fun String.extensionReceiver(): String = TODO()
+
+fun valueParameter(c: CharSequence): CharSequence = TODO()
+fun valueParameter(s: String): CharSequence = TODO()
+
+fun <R> foo(f: (String) -> R) {}

compiler/testData/diagnostics/tests/callableReference/resolve/chooseMostSpecificCandidateUsingCandidateDescriptorNotReflectionType.txt

@@ -0,0 +1,8 @@
+package
+
+public fun </*0*/ R> foo(/*0*/ f: (kotlin.String) -> R): kotlin.Unit
+public fun test(): kotlin.Unit
+public fun valueParameter(/*0*/ c: kotlin.CharSequence): kotlin.CharSequence
+public fun valueParameter(/*0*/ s: kotlin.String): kotlin.CharSequence
+public fun kotlin.CharSequence.extensionReceiver(): kotlin.CharSequence
+public fun kotlin.String.extensionReceiver(): kotlin.String

compiler/tests/org/jetbrains/kotlin/checkers/DiagnosticsTestGenerated.java

@@ -2525,6 +2525,11 @@ public class DiagnosticsTestGenerated extends AbstractDiagnosticsTest {
                     runTest("compiler/testData/diagnostics/tests/callableReference/resolve/chooseCallableReferenceDependingOnInferredReceiver.kt");
                 }
 
+                @TestMetadata("chooseMostSpecificCandidateUsingCandidateDescriptorNotReflectionType.kt")
+                public void testChooseMostSpecificCandidateUsingCandidateDescriptorNotReflectionType() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/callableReference/resolve/chooseMostSpecificCandidateUsingCandidateDescriptorNotReflectionType.kt");
+                }
+
                 @TestMetadata("chooseOuterCallBySingleCallableReference.kt")
                 public void testChooseOuterCallBySingleCallableReference() throws Exception {
                     runTest("compiler/testData/diagnostics/tests/callableReference/resolve/chooseOuterCallBySingleCallableReference.kt");

compiler/tests/org/jetbrains/kotlin/checkers/javac/DiagnosticsUsingJavacTestGenerated.java

@@ -2520,6 +2520,11 @@ public class DiagnosticsUsingJavacTestGenerated extends AbstractDiagnosticsUsing
                     runTest("compiler/testData/diagnostics/tests/callableReference/resolve/chooseCallableReferenceDependingOnInferredReceiver.kt");
                 }
 
+                @TestMetadata("chooseMostSpecificCandidateUsingCandidateDescriptorNotReflectionType.kt")
+                public void testChooseMostSpecificCandidateUsingCandidateDescriptorNotReflectionType() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/callableReference/resolve/chooseMostSpecificCandidateUsingCandidateDescriptorNotReflectionType.kt");
+                }
+
                 @TestMetadata("chooseOuterCallBySingleCallableReference.kt")
                 public void testChooseOuterCallBySingleCallableReference() throws Exception {
                     runTest("compiler/testData/diagnostics/tests/callableReference/resolve/chooseOuterCallBySingleCallableReference.kt");

core/descriptors/src/org/jetbrains/kotlin/builtins/functionTypes.kt

@@ -140,12 +140,13 @@ fun KotlinType.getValueParameterTypesFromFunctionType(): List<TypeProjection> {
     return arguments.subList(first, last)
 }
 
-fun KotlinType.getAllParameterProjectionsFromCallableReflectionType(): List<TypeProjection> {
+fun KotlinType.getValueParameterTypesFromCallableReflectionType(withReceiver: Boolean): List<TypeProjection> {
     assert(ReflectionTypes.isKCallableType(this)) { "Not a callable reflection type: $this" }
     val arguments = arguments
+    val first = if (withReceiver) 0 else 1
     val last = arguments.size - 1
-    assert(last >= 0) { "Unexpected number of type arguments in type: $this" }
-    return arguments.subList(0, last)
+    assert(first <= last) { "Not an exact function type: $this" }
+    return arguments.subList(first, last)
 }
 
 fun KotlinType.extractParameterNameFromFunctionTypeArgument(): Name? {