[FIR] Prohibit class literals with empty left-hand side

^KT-59165 Fixed

analysis/analysis-api-fir/src/org/jetbrains/kotlin/analysis/api/fir/diagnostics/KtFirDataClassConverters.kt

@@ -2440,6 +2440,12 @@ internal val KT_DIAGNOSTIC_CONVERTER = KtDiagnosticConverterBuilder.buildConvert
             token,
         )
     }
+    add(FirErrors.UNSUPPORTED_CLASS_LITERALS_WITH_EMPTY_LHS) { firDiagnostic ->
+        UnsupportedClassLiteralsWithEmptyLhsImpl(
+            firDiagnostic as KtPsiDiagnostic,
+            token,
+        )
+    }
     add(FirErrors.NOTHING_TO_OVERRIDE) { firDiagnostic ->
         NothingToOverrideImpl(
             firSymbolBuilder.callableBuilder.buildCallableSymbol(firDiagnostic.a),

analysis/analysis-api-fir/src/org/jetbrains/kotlin/analysis/api/fir/diagnostics/KtFirDiagnostics.kt

@@ -1730,6 +1730,10 @@ sealed interface KtFirDiagnostic<PSI : PsiElement> : KtDiagnosticWithPsi<PSI> {
         val lhsType: KtType
     }
 
+    interface UnsupportedClassLiteralsWithEmptyLhs : KtFirDiagnostic<KtElement> {
+        override val diagnosticClass get() = UnsupportedClassLiteralsWithEmptyLhs::class
+    }
+
     interface NothingToOverride : KtFirDiagnostic<KtModifierListOwner> {
         override val diagnosticClass get() = NothingToOverride::class
         val declaration: KtCallableSymbol

analysis/analysis-api-fir/src/org/jetbrains/kotlin/analysis/api/fir/diagnostics/KtFirDiagnosticsImpl.kt

@@ -2080,6 +2080,11 @@ internal class ExpressionOfNullableTypeInClassLiteralLhsImpl(
     token: KtLifetimeToken,
 ) : KtAbstractFirDiagnostic<PsiElement>(firDiagnostic, token), KtFirDiagnostic.ExpressionOfNullableTypeInClassLiteralLhs
 
+internal class UnsupportedClassLiteralsWithEmptyLhsImpl(
+    firDiagnostic: KtPsiDiagnostic,
+    token: KtLifetimeToken,
+) : KtAbstractFirDiagnostic<KtElement>(firDiagnostic, token), KtFirDiagnostic.UnsupportedClassLiteralsWithEmptyLhs
+
 internal class NothingToOverrideImpl(
     override val declaration: KtCallableSymbol,
     firDiagnostic: KtPsiDiagnostic,

analysis/low-level-api-fir/tests/org/jetbrains/kotlin/analysis/low/level/api/fir/diagnostic/compiler/based/DiagnosticCompilerTestFE10TestdataTestGenerated.java

@@ -297,6 +297,12 @@ public class DiagnosticCompilerTestFE10TestdataTestGenerated extends AbstractDia
             runTest("compiler/testData/diagnostics/tests/Dollar.kt");
         }
 
+        @Test
+        @TestMetadata("emptyLhsClassLiterals.kt")
+        public void testEmptyLhsClassLiterals() throws Exception {
+            runTest("compiler/testData/diagnostics/tests/emptyLhsClassLiterals.kt");
+        }
+
         @Test
         @TestMetadata("EnumEntryAsType.kt")
         public void testEnumEntryAsType() throws Exception {

analysis/low-level-api-fir/tests/org/jetbrains/kotlin/analysis/low/level/api/fir/diagnostic/compiler/based/LLFirPreresolvedReversedDiagnosticCompilerFE10TestDataTestGenerated.java

@@ -297,6 +297,12 @@ public class LLFirPreresolvedReversedDiagnosticCompilerFE10TestDataTestGenerated
             runTest("compiler/testData/diagnostics/tests/Dollar.kt");
         }
 
+        @Test
+        @TestMetadata("emptyLhsClassLiterals.kt")
+        public void testEmptyLhsClassLiterals() throws Exception {
+            runTest("compiler/testData/diagnostics/tests/emptyLhsClassLiterals.kt");
+        }
+
         @Test
         @TestMetadata("EnumEntryAsType.kt")
         public void testEnumEntryAsType() throws Exception {

compiler/fir/analysis-tests/tests-gen/org/jetbrains/kotlin/test/runners/FirLightTreeOldFrontendDiagnosticsTestGenerated.java

@@ -297,6 +297,12 @@ public class FirLightTreeOldFrontendDiagnosticsTestGenerated extends AbstractFir
             runTest("compiler/testData/diagnostics/tests/Dollar.kt");
         }
 
+        @Test
+        @TestMetadata("emptyLhsClassLiterals.kt")
+        public void testEmptyLhsClassLiterals() throws Exception {
+            runTest("compiler/testData/diagnostics/tests/emptyLhsClassLiterals.kt");
+        }
+
         @Test
         @TestMetadata("EnumEntryAsType.kt")
         public void testEnumEntryAsType() throws Exception {

compiler/fir/analysis-tests/tests-gen/org/jetbrains/kotlin/test/runners/FirPsiOldFrontendDiagnosticsTestGenerated.java

@@ -297,6 +297,12 @@ public class FirPsiOldFrontendDiagnosticsTestGenerated extends AbstractFirPsiDia
             runTest("compiler/testData/diagnostics/tests/Dollar.kt");
         }
 
+        @Test
+        @TestMetadata("emptyLhsClassLiterals.kt")
+        public void testEmptyLhsClassLiterals() throws Exception {
+            runTest("compiler/testData/diagnostics/tests/emptyLhsClassLiterals.kt");
+        }
+
         @Test
         @TestMetadata("EnumEntryAsType.kt")
         public void testEnumEntryAsType() throws Exception {

compiler/fir/checkers/checkers-component-generator/src/org/jetbrains/kotlin/fir/checkers/generator/diagnostics/FirDiagnosticsList.kt

@@ -806,6 +806,7 @@ object DIAGNOSTICS_LIST : DiagnosticList("FirErrors") {
         val EXPRESSION_OF_NULLABLE_TYPE_IN_CLASS_LITERAL_LHS by error<PsiElement> {
             parameter<ConeKotlinType>("lhsType")
         }
+        val UNSUPPORTED_CLASS_LITERALS_WITH_EMPTY_LHS by error<KtElement>()
     }
 
     val OVERRIDES by object : DiagnosticGroup("overrides") {

compiler/fir/checkers/gen/org/jetbrains/kotlin/fir/analysis/diagnostics/FirErrors.kt

@@ -463,6 +463,7 @@ object FirErrors {
     val CLASS_LITERAL_LHS_NOT_A_CLASS by error0<KtExpression>()
     val NULLABLE_TYPE_IN_CLASS_LITERAL_LHS by error0<KtExpression>()
     val EXPRESSION_OF_NULLABLE_TYPE_IN_CLASS_LITERAL_LHS by error1<PsiElement, ConeKotlinType>()
+    val UNSUPPORTED_CLASS_LITERALS_WITH_EMPTY_LHS by error0<KtElement>()
 
     // overrides
     val NOTHING_TO_OVERRIDE by error1<KtModifierListOwner, FirCallableSymbol<*>>(SourceElementPositioningStrategies.OVERRIDE_MODIFIER)

compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/diagnostics/FirErrorsDefaultMessages.kt

@@ -595,6 +595,7 @@ import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.UNSAFE_INFIX_CALL
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.UNSAFE_OPERATOR_CALL
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.UNSIGNED_LITERAL_WITHOUT_DECLARATIONS_ON_CLASSPATH
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.UNSUPPORTED
+import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.UNSUPPORTED_CLASS_LITERALS_WITH_EMPTY_LHS
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.UNSUPPORTED_CONTEXTUAL_DECLARATION_CALL
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.UNSUPPORTED_FEATURE
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.UNUSED_VARIABLE
@@ -1359,6 +1360,7 @@ object FirErrorsDefaultMessages : BaseDiagnosticRendererFactory() {
             "Expression in a class literal has a nullable type ''{0}'', use !! to make the type non-nullable",
             RENDER_TYPE
         )
+        map.put(UNSUPPORTED_CLASS_LITERALS_WITH_EMPTY_LHS, "Class literals with empty left hand side are unsupported")
 
         // Value classes
         map.put(VALUE_CLASS_NOT_TOP_LEVEL, "Value class cannot be local or inner")
@@ -2002,7 +2004,7 @@ object FirErrorsDefaultMessages : BaseDiagnosticRendererFactory() {
         map.put(USELESS_CAST, "No cast needed")
         map.put(UNCHECKED_CAST, "Unchecked cast: ''{0}'' to ''{1}''", RENDER_TYPE, RENDER_TYPE)
         map.put(USELESS_IS_CHECK, "Check for instance is always ''{0}''", TO_STRING)
-        map.put(DYNAMIC_NOT_ALLOWED, "Dynamic types are not allowed in this position");
+        map.put(DYNAMIC_NOT_ALLOWED, "Dynamic types are not allowed in this position")
         map.put(IS_ENUM_ENTRY, "'is' over enum entry is not allowed, use comparison instead")
         map.put(ENUM_ENTRY_AS_TYPE, "Use of enum entry names as types is not allowed, use enum type instead")
 

compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/diagnostics/coneDiagnosticToFirDiagnostic.kt

@@ -151,6 +151,7 @@ private fun ConeDiagnostic.toKtDiagnostic(
     is ConeAmbiguouslyResolvedAnnotationArgument ->
         FirErrors.AMBIGUOUS_ANNOTATION_ARGUMENT.createOn(source, listOfNotNull(symbolFromCompilerPhase, symbolFromAnnotationArgumentsPhase))
     is ConeAmbiguousFunctionTypeKinds -> FirErrors.AMBIGUOUS_FUNCTION_TYPE_KIND.createOn(source, kinds)
+    is ConeUnsupportedClassLiteralsWithEmptyLhs -> FirErrors.UNSUPPORTED_CLASS_LITERALS_WITH_EMPTY_LHS.createOn(source)
     else -> throw IllegalArgumentException("Unsupported diagnostic type: ${this.javaClass}")
 }
 

compiler/fir/raw-fir/light-tree2fir/src/org/jetbrains/kotlin/fir/lightTree/converter/LightTreeRawFirExpressionBuilder.kt

@@ -463,11 +463,13 @@ class LightTreeRawFirExpressionBuilder(
             if (it.isExpression()) firReceiverExpression = getAsFirExpression(it, "No receiver in class literal")
         }
 
+        val classLiteralSource = classLiteralExpression.toFirSourceElement()
+
         return buildGetClassCall {
-            source = classLiteralExpression.toFirSourceElement()
+            source = classLiteralSource
             argumentList = buildUnaryArgumentList(
                 firReceiverExpression
-                    ?: buildErrorExpression(null, ConeSyntaxDiagnostic("No receiver in class literal"))
+                    ?: buildErrorExpression(classLiteralSource, ConeUnsupportedClassLiteralsWithEmptyLhs)
             )
         }
     }

compiler/fir/raw-fir/psi2fir/src/org/jetbrains/kotlin/fir/builder/PsiRawFirBuilder.kt

@@ -276,9 +276,12 @@ open class PsiRawFirBuilder(
             kind: DiagnosticKind = DiagnosticKind.ExpressionExpected
         ): FirExpression = toFirExpression { ConeSimpleDiagnostic(errorReason, kind) }
 
-        private inline fun KtElement?.toFirExpression(diagnosticFn: () -> ConeDiagnostic): FirExpression {
+        private inline fun KtElement?.toFirExpression(
+            sourceWhenThisIsNull: PsiElement? = null,
+            diagnosticFn: () -> ConeDiagnostic,
+        ): FirExpression {
             if (this == null) {
-                return buildErrorExpression(source = null, diagnosticFn())
+                return buildErrorExpression(source = sourceWhenThisIsNull?.toFirSourceElement(), diagnosticFn())
             }
 
             val result = when (val fir = convertElement(this, null)) {
@@ -2929,7 +2932,11 @@ open class PsiRawFirBuilder(
         override fun visitClassLiteralExpression(expression: KtClassLiteralExpression, data: FirElement?): FirElement {
             return buildGetClassCall {
                 source = expression.toFirSourceElement()
-                argumentList = buildUnaryArgumentList(expression.receiverExpression.toFirExpression("No receiver in class literal"))
+                argumentList = buildUnaryArgumentList(
+                    expression.receiverExpression.toFirExpression(sourceWhenThisIsNull = expression) {
+                        ConeUnsupportedClassLiteralsWithEmptyLhs
+                    }
+                )
             }
         }
 

compiler/fir/tree/src/org/jetbrains/kotlin/fir/diagnostics/ConeSimpleDiagnostic.kt

@@ -71,6 +71,10 @@ class ConeAmbiguousFunctionTypeKinds(val kinds: List<FunctionTypeKind>) : ConeDi
         get() = "There are multiple function kinds for functional type ref"
 }
 
+object ConeUnsupportedClassLiteralsWithEmptyLhs : ConeDiagnostic {
+    override val reason: String get() = "No receiver in class literal"
+}
+
 enum class DiagnosticKind {
     ExpressionExpected,
     NotLoopLabel,

compiler/testData/diagnostics/tests/callableReference/unsupported/classLiteralsWithEmptyLHS.fir.kt

@@ -1,17 +0,0 @@
-fun regular() {
-    ::class
-
-    with(Any()) {
-        ::class
-    }
-}
-
-fun Any.extension() {
-    ::class
-}
-
-class A {
-    fun member() {
-        ::class
-    }
-}

compiler/testData/diagnostics/tests/callableReference/unsupported/classLiteralsWithEmptyLHS.kt

@@ -1,3 +1,4 @@
+// FIR_IDENTICAL
 fun regular() {
     <!UNSUPPORTED_CLASS_LITERALS_WITH_EMPTY_LHS!>::class<!>
 

compiler/testData/diagnostics/tests/emptyLhsClassLiterals.kt

@@ -0,0 +1,6 @@
+// FIR_IDENTICAL
+// ISSUE: KT-59165
+
+fun regular() {
+    <!UNSUPPORTED_CLASS_LITERALS_WITH_EMPTY_LHS!>::class<!> // K1: Error, K2: compiles
+}

compiler/tests-common-new/tests-gen/org/jetbrains/kotlin/test/runners/DiagnosticTestGenerated.java

@@ -297,6 +297,12 @@ public class DiagnosticTestGenerated extends AbstractDiagnosticTest {
             runTest("compiler/testData/diagnostics/tests/Dollar.kt");
         }
 
+        @Test
+        @TestMetadata("emptyLhsClassLiterals.kt")
+        public void testEmptyLhsClassLiterals() throws Exception {
+            runTest("compiler/testData/diagnostics/tests/emptyLhsClassLiterals.kt");
+        }
+
         @Test
         @TestMetadata("EnumEntryAsType.kt")
         public void testEnumEntryAsType() throws Exception {