Compatibility warning for references to companion via name (KT-13934)

compiler/fir/analysis-tests/tests/org/jetbrains/kotlin/fir/FirOldFrontendDiagnosticsTestGenerated.java

@@ -1939,6 +1939,16 @@ public class FirOldFrontendDiagnosticsTestGenerated extends AbstractFirOldFronte
             runTest("compiler/testData/diagnostics/tests/callableReference/referenceAdaptationCompatibility.kt");
         }
 
+        @TestMetadata("referenceToCompanionObjectMemberViaClassName.kt")
+        public void testReferenceToCompanionObjectMemberViaClassName() throws Exception {
+            runTest("compiler/testData/diagnostics/tests/callableReference/referenceToCompanionObjectMemberViaClassName.kt");
+        }
+
+        @TestMetadata("referenceToCompanionObjectMemberViaClassNameCompatibility.kt")
+        public void testReferenceToCompanionObjectMemberViaClassNameCompatibility() throws Exception {
+            runTest("compiler/testData/diagnostics/tests/callableReference/referenceToCompanionObjectMemberViaClassNameCompatibility.kt");
+        }
+
         @TestMetadata("rewriteAtSliceOnGetOperator.kt")
         public void testRewriteAtSliceOnGetOperator() throws Exception {
             runTest("compiler/testData/diagnostics/tests/callableReference/rewriteAtSliceOnGetOperator.kt");

compiler/fir/fir2ir/tests/org/jetbrains/kotlin/codegen/ir/FirBlackBoxCodegenTestGenerated.java

@@ -2685,6 +2685,11 @@ public class FirBlackBoxCodegenTestGenerated extends AbstractFirBlackBoxCodegenT
                 runTest("compiler/testData/codegen/box/callableReference/function/privateClassMember.kt");
             }
 
+            @TestMetadata("referenceToCompanionMember.kt")
+            public void testReferenceToCompanionMember() throws Exception {
+                runTest("compiler/testData/codegen/box/callableReference/function/referenceToCompanionMember.kt");
+            }
+
             @TestMetadata("sortListOfStrings.kt")
             public void testSortListOfStrings() throws Exception {
                 runTest("compiler/testData/codegen/box/callableReference/function/sortListOfStrings.kt");

compiler/resolution/src/org/jetbrains/kotlin/resolve/calls/components/CallableReferenceResolution.kt

@@ -20,6 +20,7 @@ import org.jetbrains.kotlin.resolve.calls.tasks.ExplicitReceiverKind.DISPATCH_RE
 import org.jetbrains.kotlin.resolve.calls.tasks.ExplicitReceiverKind.EXTENSION_RECEIVER
 import org.jetbrains.kotlin.resolve.calls.tower.*
 import org.jetbrains.kotlin.resolve.descriptorUtil.builtIns
+import org.jetbrains.kotlin.resolve.descriptorUtil.isCompanionObject
 import org.jetbrains.kotlin.resolve.scopes.receivers.DetailedReceiver
 import org.jetbrains.kotlin.resolve.scopes.receivers.ReceiverValue
 import org.jetbrains.kotlin.resolve.scopes.receivers.ReceiverValueWithSmartCastInfo
@@ -213,7 +214,7 @@ class CallableReferencesCandidateFactory(
             callComponents.builtIns
         )
 
-        if (needCompatibilityWarning(callableReferenceAdaptation)) {
+        if (needCompatibilityWarning(callableReferenceAdaptation, candidateDescriptor)) {
             diagnostics.add(LowerPriorityToPreserveCompatibility)
         }
 
@@ -261,7 +262,13 @@ class CallableReferencesCandidateFactory(
         )
     }
 
-    private fun needCompatibilityWarning(callableReferenceAdaptation: CallableReferenceAdaptation?): Boolean {
+    private fun needCompatibilityWarning(
+        callableReferenceAdaptation: CallableReferenceAdaptation?,
+        candidate: CallableDescriptor
+    ): Boolean {
+        // KT-13934: reference to companion object member via class name
+        if (candidate.containingDeclaration.isCompanionObject() && argument.lhsResult is LHSResult.Type) return true
+
         if (callableReferenceAdaptation == null) return false
 
         return callableReferenceAdaptation.defaults != 0 ||

compiler/testData/codegen/box/callableReference/function/referenceToCompanionMember.kt

+// WITH_RUNTIME
+// IGNORE_BACKEND_FIR: JVM_IR
+// IGNORE_BACKEND: JS
+
+class A {
+    companion object {
+        fun foo(): String = "OK"
+    }
+}
+
+class B {
+    companion object {
+        fun foo(): String = "Fail"
+    }
+}
+
+fun B.foo(): String = "OK"
+
+fun call(f: Any): String = if (f is Function0<*>) f.invoke() as String else (f as Function1<B, String>).invoke(B())
+
+fun box(): String {
+    val call1 = call(A::foo)
+    if (call1 != "OK") return "fail 1: $call1"
+
+    // Checking compatibility mode: should be resolved to extensions in 1.4
+    val call2 = call(B::foo)
+    if (call2 != "OK") return "fail 2: $call2"
+
+    return "OK"
+}
+
+

compiler/testData/diagnostics/tests/callableReference/referenceToCompanionObjectMemberViaClassName.kt

+// FIR_IDENTICAL
+// !DIAGNOSTICS: -UNUSED_EXPRESSION -UNUSED_PARAMETER
+
+class A {
+    companion object {
+        fun foo(): Int = 0
+    }
+}
+
+class B {
+    fun foo(): String = ""
+
+    companion object {
+        fun foo(): Int = 0
+    }
+}
+
+fun <T> call(f: () -> T): T = f()
+
+fun testA(a: A) {
+    val call1 = call(A::foo)
+    <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Int")!>call1<!>
+
+    val call2 = call(A.Companion::foo)
+    <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Int")!>call2<!>
+}
+
+fun testB(b: B) {
+    val call1 = call(B::foo)
+    <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Int")!>call1<!>
+
+    val call2 = call(B()::foo)
+    <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.String")!>call2<!>
+
+    val call3 = call(B.Companion::foo)
+    <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Int")!>call3<!>
+}

compiler/testData/diagnostics/tests/callableReference/referenceToCompanionObjectMemberViaClassName.txt

+package
+
+public fun </*0*/ T> call(/*0*/ f: () -> T): T
+public fun testA(/*0*/ a: A): kotlin.Unit
+public fun testB(/*0*/ b: B): kotlin.Unit
+
+public final class A {
+    public constructor A()
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+    public companion object Companion {
+        private constructor Companion()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public final fun foo(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+}
+
+public final class B {
+    public constructor B()
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public final fun foo(): kotlin.String
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+    public companion object Companion {
+        private constructor Companion()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public final fun foo(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+}

compiler/testData/diagnostics/tests/callableReference/referenceToCompanionObjectMemberViaClassNameCompatibility.fir.kt

+// !DIAGNOSTICS: -UNUSED_EXPRESSION -UNUSED_PARAMETER
+
+class A {
+    companion object {
+        fun foo(): Int = 0
+    }
+}
+
+fun A.foo(): Double = 0.0
+fun Any.foo(): Float = 1f
+
+class B {
+    fun foo(): String = ""
+
+    companion object {
+        fun foo(): Int = 0
+    }
+}
+
+fun B.foo(): Double = 0.0
+
+fun call(a: Any) {}
+
+fun testA(a: A) {
+    call(A::foo)
+    call(A.Companion::foo)
+}
+
+fun testB(b: B) {
+    call(B::foo)
+    call(B()::foo)
+    call(B.Companion::foo)
+}

compiler/testData/diagnostics/tests/callableReference/referenceToCompanionObjectMemberViaClassNameCompatibility.kt

+// !DIAGNOSTICS: -UNUSED_EXPRESSION -UNUSED_PARAMETER
+
+class A {
+    companion object {
+        fun foo(): Int = 0
+    }
+}
+
+fun A.foo(): Double = 0.0
+fun Any.foo(): Float = 1f
+
+class B {
+    fun foo(): String = ""
+
+    companion object {
+        fun foo(): Int = 0
+    }
+}
+
+fun B.<!EXTENSION_SHADOWED_BY_MEMBER!>foo<!>(): Double = 0.0
+
+fun call(a: Any) {}
+
+fun testA(a: A) {
+    call(<!COMPATIBILITY_WARNING!>A::foo<!>)
+    call(A.Companion::foo)
+}
+
+fun testB(b: B) {
+    call(B::foo)
+    call(B()::foo)
+    call(B.Companion::foo)
+}

compiler/testData/diagnostics/tests/callableReference/referenceToCompanionObjectMemberViaClassNameCompatibility.txt

+package
+
+public fun call(/*0*/ a: kotlin.Any): kotlin.Unit
+public fun testA(/*0*/ a: A): kotlin.Unit
+public fun testB(/*0*/ b: B): kotlin.Unit
+public fun A.foo(): kotlin.Double
+public fun B.foo(): kotlin.Double
+public fun kotlin.Any.foo(): kotlin.Float
+
+public final class A {
+    public constructor A()
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+    public companion object Companion {
+        private constructor Companion()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public final fun foo(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+}
+
+public final class B {
+    public constructor B()
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public final fun foo(): kotlin.String
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+    public companion object Companion {
+        private constructor Companion()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public final fun foo(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+}

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

@@ -1946,6 +1946,16 @@ public class DiagnosticsTestGenerated extends AbstractDiagnosticsTestWithFirVali
                 runTest("compiler/testData/diagnostics/tests/callableReference/referenceAdaptationCompatibility.kt");
             }
 
+            @TestMetadata("referenceToCompanionObjectMemberViaClassName.kt")
+            public void testReferenceToCompanionObjectMemberViaClassName() throws Exception {
+                runTest("compiler/testData/diagnostics/tests/callableReference/referenceToCompanionObjectMemberViaClassName.kt");
+            }
+
+            @TestMetadata("referenceToCompanionObjectMemberViaClassNameCompatibility.kt")
+            public void testReferenceToCompanionObjectMemberViaClassNameCompatibility() throws Exception {
+                runTest("compiler/testData/diagnostics/tests/callableReference/referenceToCompanionObjectMemberViaClassNameCompatibility.kt");
+            }
+
             @TestMetadata("rewriteAtSliceOnGetOperator.kt")
             public void testRewriteAtSliceOnGetOperator() throws Exception {
                 runTest("compiler/testData/diagnostics/tests/callableReference/rewriteAtSliceOnGetOperator.kt");

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

@@ -1941,6 +1941,16 @@ public class DiagnosticsUsingJavacTestGenerated extends AbstractDiagnosticsUsing
                 runTest("compiler/testData/diagnostics/tests/callableReference/referenceAdaptationCompatibility.kt");
             }
 
+            @TestMetadata("referenceToCompanionObjectMemberViaClassName.kt")
+            public void testReferenceToCompanionObjectMemberViaClassName() throws Exception {
+                runTest("compiler/testData/diagnostics/tests/callableReference/referenceToCompanionObjectMemberViaClassName.kt");
+            }
+
+            @TestMetadata("referenceToCompanionObjectMemberViaClassNameCompatibility.kt")
+            public void testReferenceToCompanionObjectMemberViaClassNameCompatibility() throws Exception {
+                runTest("compiler/testData/diagnostics/tests/callableReference/referenceToCompanionObjectMemberViaClassNameCompatibility.kt");
+            }
+
             @TestMetadata("rewriteAtSliceOnGetOperator.kt")
             public void testRewriteAtSliceOnGetOperator() throws Exception {
                 runTest("compiler/testData/diagnostics/tests/callableReference/rewriteAtSliceOnGetOperator.kt");

compiler/tests/org/jetbrains/kotlin/codegen/BlackBoxCodegenTestGenerated.java

@@ -2705,6 +2705,11 @@ public class BlackBoxCodegenTestGenerated extends AbstractBlackBoxCodegenTest {
                 runTest("compiler/testData/codegen/box/callableReference/function/privateClassMember.kt");
             }
 
+            @TestMetadata("referenceToCompanionMember.kt")
+            public void testReferenceToCompanionMember() throws Exception {
+                runTest("compiler/testData/codegen/box/callableReference/function/referenceToCompanionMember.kt");
+            }
+
             @TestMetadata("sortListOfStrings.kt")
             public void testSortListOfStrings() throws Exception {
                 runTest("compiler/testData/codegen/box/callableReference/function/sortListOfStrings.kt");

compiler/tests/org/jetbrains/kotlin/codegen/LightAnalysisModeTestGenerated.java

@@ -2705,6 +2705,11 @@ public class LightAnalysisModeTestGenerated extends AbstractLightAnalysisModeTes
                 runTest("compiler/testData/codegen/box/callableReference/function/privateClassMember.kt");
             }
 
+            @TestMetadata("referenceToCompanionMember.kt")
+            public void testReferenceToCompanionMember() throws Exception {
+                runTest("compiler/testData/codegen/box/callableReference/function/referenceToCompanionMember.kt");
+            }
+
             @TestMetadata("sortListOfStrings.kt")
             public void testSortListOfStrings() throws Exception {
                 runTest("compiler/testData/codegen/box/callableReference/function/sortListOfStrings.kt");

compiler/tests/org/jetbrains/kotlin/codegen/ir/IrBlackBoxCodegenTestGenerated.java

@@ -2685,6 +2685,11 @@ public class IrBlackBoxCodegenTestGenerated extends AbstractIrBlackBoxCodegenTes
                 runTest("compiler/testData/codegen/box/callableReference/function/privateClassMember.kt");
             }
 
+            @TestMetadata("referenceToCompanionMember.kt")
+            public void testReferenceToCompanionMember() throws Exception {
+                runTest("compiler/testData/codegen/box/callableReference/function/referenceToCompanionMember.kt");
+            }
+
             @TestMetadata("sortListOfStrings.kt")
             public void testSortListOfStrings() throws Exception {
                 runTest("compiler/testData/codegen/box/callableReference/function/sortListOfStrings.kt");

js/js.tests/test/org/jetbrains/kotlin/js/test/es6/semantics/IrJsCodegenBoxES6TestGenerated.java

@@ -2065,6 +2065,11 @@ public class IrJsCodegenBoxES6TestGenerated extends AbstractIrJsCodegenBoxES6Tes
                 runTest("compiler/testData/codegen/box/callableReference/function/privateClassMember.kt");
             }
 
+            @TestMetadata("referenceToCompanionMember.kt")
+            public void testReferenceToCompanionMember() throws Exception {
+                runTest("compiler/testData/codegen/box/callableReference/function/referenceToCompanionMember.kt");
+            }
+
             @TestMetadata("sortListOfStrings.kt")
             public void testSortListOfStrings() throws Exception {
                 runTest("compiler/testData/codegen/box/callableReference/function/sortListOfStrings.kt");

js/js.tests/test/org/jetbrains/kotlin/js/test/ir/semantics/IrJsCodegenBoxTestGenerated.java

@@ -2075,6 +2075,11 @@ public class IrJsCodegenBoxTestGenerated extends AbstractIrJsCodegenBoxTest {
                 runTest("compiler/testData/codegen/box/callableReference/function/privateClassMember.kt");
             }
 
+            @TestMetadata("referenceToCompanionMember.kt")
+            public void testReferenceToCompanionMember() throws Exception {
+                runTest("compiler/testData/codegen/box/callableReference/function/referenceToCompanionMember.kt");
+            }
+
             @TestMetadata("sortListOfStrings.kt")
             public void testSortListOfStrings() throws Exception {
                 runTest("compiler/testData/codegen/box/callableReference/function/sortListOfStrings.kt");

js/js.tests/test/org/jetbrains/kotlin/js/test/semantics/JsCodegenBoxTestGenerated.java

@@ -2075,6 +2075,11 @@ public class JsCodegenBoxTestGenerated extends AbstractJsCodegenBoxTest {
                 runTest("compiler/testData/codegen/box/callableReference/function/privateClassMember.kt");
             }
 
+            @TestMetadata("referenceToCompanionMember.kt")
+            public void testReferenceToCompanionMember() throws Exception {
+                runTest("compiler/testData/codegen/box/callableReference/function/referenceToCompanionMember.kt");
+            }
+
             @TestMetadata("sortListOfStrings.kt")
             public void testSortListOfStrings() throws Exception {
                 runTest("compiler/testData/codegen/box/callableReference/function/sortListOfStrings.kt");