K2: Rework scopes for types with projection arguments for Out types

The only case when behavior is change is described at
 computeNonTrivialTypeArgumentForScopeSubstitutor

The idea is to avoid depending on the presence of @UnsafeVariance
and instead approximate captured types in covariant argument positions
before building substitution scopes

It's correct because for Captured(*) <: Supertype,
Out<Captured(*)> <: Out<Supertype> and when we've got @UnsafeVariance
value parameters at Out, it's ok to allow passing Supertype there.

^KT-57602 Fixed
^KT-54894 Fixed

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

@@ -28149,6 +28149,34 @@ public class DiagnosticCompilerTestFE10TestdataTestGenerated extends AbstractDia
                     runTest("compiler/testData/diagnostics/tests/scopes/protectedVisibility/withSmartcast.kt");
                 }
             }
+
+            @Nested
+            @TestMetadata("compiler/testData/diagnostics/tests/scopes/variantProjections")
+            @TestDataPath("$PROJECT_ROOT")
+            public class VariantProjections {
+                @Test
+                public void testAllFilesPresentInVariantProjections() throws Exception {
+                    KtTestUtil.assertAllTestsPresentByMetadataWithExcluded(this.getClass(), new File("compiler/testData/diagnostics/tests/scopes/variantProjections"), Pattern.compile("^(.+)\\.kt$"), Pattern.compile("^(.+)\\.(reversed|fir|ll)\\.kts?$"), true, "multiplatform");
+                }
+
+                @Test
+                @TestMetadata("dataClassCopy.kt")
+                public void testDataClassCopy() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/scopes/variantProjections/dataClassCopy.kt");
+                }
+
+                @Test
+                @TestMetadata("interdependentStarProjections.kt")
+                public void testInterdependentStarProjections() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/scopes/variantProjections/interdependentStarProjections.kt");
+                }
+
+                @Test
+                @TestMetadata("unsafeVarianceAndCovariantProjection.kt")
+                public void testUnsafeVarianceAndCovariantProjection() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/scopes/variantProjections/unsafeVarianceAndCovariantProjection.kt");
+                }
+            }
         }
 
         @Nested

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

@@ -28149,6 +28149,34 @@ public class LLFirPreresolvedReversedDiagnosticCompilerFE10TestDataTestGenerated
                     runTest("compiler/testData/diagnostics/tests/scopes/protectedVisibility/withSmartcast.kt");
                 }
             }
+
+            @Nested
+            @TestMetadata("compiler/testData/diagnostics/tests/scopes/variantProjections")
+            @TestDataPath("$PROJECT_ROOT")
+            public class VariantProjections {
+                @Test
+                public void testAllFilesPresentInVariantProjections() throws Exception {
+                    KtTestUtil.assertAllTestsPresentByMetadataWithExcluded(this.getClass(), new File("compiler/testData/diagnostics/tests/scopes/variantProjections"), Pattern.compile("^(.+)\\.kt$"), Pattern.compile("^(.+)\\.(reversed|fir|ll)\\.kts?$"), true, "multiplatform");
+                }
+
+                @Test
+                @TestMetadata("dataClassCopy.kt")
+                public void testDataClassCopy() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/scopes/variantProjections/dataClassCopy.kt");
+                }
+
+                @Test
+                @TestMetadata("interdependentStarProjections.kt")
+                public void testInterdependentStarProjections() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/scopes/variantProjections/interdependentStarProjections.kt");
+                }
+
+                @Test
+                @TestMetadata("unsafeVarianceAndCovariantProjection.kt")
+                public void testUnsafeVarianceAndCovariantProjection() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/scopes/variantProjections/unsafeVarianceAndCovariantProjection.kt");
+                }
+            }
         }
 
         @Nested

compiler/fir/analysis-tests/testData/resolve/cfg/complex.dot

@@ -185,7 +185,7 @@ digraph complex_kt {
                 color=blue
                 55 [label="Enter block"];
                 56 [label="Access variable this@R|/firstIsInstanceOrNull|"];
-                57 [label="Function call: this@R|/firstIsInstanceOrNull|.R|SubstitutionOverride<kotlin/collections/List.iterator: R|kotlin/collections/Iterator<CapturedType(*)>|>|()" style="filled" fillcolor=yellow];
+                57 [label="Function call: this@R|/firstIsInstanceOrNull|.R|SubstitutionOverride<kotlin/collections/List.iterator: R|kotlin/collections/Iterator<kotlin/Any?>|>|()" style="filled" fillcolor=yellow];
                 58 [label="Variable declaration: lval <iterator>: R|kotlin/collections/Iterator<kotlin/Any?>|"];
                 subgraph cluster_19 {
                     color=blue

compiler/fir/analysis-tests/testData/resolve/cfg/complex.fir.txt

@@ -24,7 +24,7 @@ FILE: complex.kt
     }
     public final inline fun <reified T : R|kotlin/Any|> R|kotlin/collections/List<*>|.firstIsInstanceOrNull(): R|T?| {
          {
-            lval <iterator>: R|kotlin/collections/Iterator<kotlin/Any?>| = this@R|/firstIsInstanceOrNull|.R|SubstitutionOverride<kotlin/collections/List.iterator: R|kotlin/collections/Iterator<CapturedType(*)>|>|()
+            lval <iterator>: R|kotlin/collections/Iterator<kotlin/Any?>| = this@R|/firstIsInstanceOrNull|.R|SubstitutionOverride<kotlin/collections/List.iterator: R|kotlin/collections/Iterator<kotlin/Any?>|>|()
             while(R|<local>/<iterator>|.R|SubstitutionOverride<kotlin/collections/Iterator.hasNext: R|kotlin/Boolean|>|()) {
                 lval element: R|kotlin/Any?| = R|<local>/<iterator>|.R|SubstitutionOverride<kotlin/collections/Iterator.next: R|kotlin/Any?|>|()
                  {

compiler/fir/analysis-tests/testData/resolve/typeAliasWithTypeArguments.fir.txt

@@ -77,7 +77,7 @@ FILE: typeAliasWithTypeArguments.kt
     public final fun test_6(a: R|A|, out1: R|Out1<A>|, out2: R|Out1<in A>|, out3: R|Out1<out A>|): R|kotlin/Unit| {
         R|<local>/out1|.R|SubstitutionOverride</Out.value: R|A|>|().R|/A.foo|()
         R|<local>/out2|.<Unresolved name: value>#().<Unresolved name: foo>#()
-        R|<local>/out3|.R|SubstitutionOverride</Out.value: R|CapturedType(out A)|>|().R|/A.foo|()
+        R|<local>/out3|.R|SubstitutionOverride</Out.value: R|A|>|().R|/A.foo|()
     }
     public final fun test_7(a: R|A|, inv1: R|Invariant1<A>|, inv2: R|Invariant1<in A>|, inv3: R|Invariant1<out A>|): R|kotlin/Unit| {
         R|<local>/inv1|.R|SubstitutionOverride</Invariant.value: R|A|>|().R|/A.foo|()

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

@@ -28149,6 +28149,34 @@ public class FirLightTreeOldFrontendDiagnosticsTestGenerated extends AbstractFir
                     runTest("compiler/testData/diagnostics/tests/scopes/protectedVisibility/withSmartcast.kt");
                 }
             }
+
+            @Nested
+            @TestMetadata("compiler/testData/diagnostics/tests/scopes/variantProjections")
+            @TestDataPath("$PROJECT_ROOT")
+            public class VariantProjections {
+                @Test
+                public void testAllFilesPresentInVariantProjections() throws Exception {
+                    KtTestUtil.assertAllTestsPresentByMetadataWithExcluded(this.getClass(), new File("compiler/testData/diagnostics/tests/scopes/variantProjections"), Pattern.compile("^(.+)\\.kt$"), Pattern.compile("^(.+)\\.(reversed|fir|ll)\\.kts?$"), true, "multiplatform");
+                }
+
+                @Test
+                @TestMetadata("dataClassCopy.kt")
+                public void testDataClassCopy() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/scopes/variantProjections/dataClassCopy.kt");
+                }
+
+                @Test
+                @TestMetadata("interdependentStarProjections.kt")
+                public void testInterdependentStarProjections() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/scopes/variantProjections/interdependentStarProjections.kt");
+                }
+
+                @Test
+                @TestMetadata("unsafeVarianceAndCovariantProjection.kt")
+                public void testUnsafeVarianceAndCovariantProjection() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/scopes/variantProjections/unsafeVarianceAndCovariantProjection.kt");
+                }
+            }
         }
 
         @Nested

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

@@ -28161,6 +28161,34 @@ public class FirPsiOldFrontendDiagnosticsTestGenerated extends AbstractFirPsiDia
                     runTest("compiler/testData/diagnostics/tests/scopes/protectedVisibility/withSmartcast.kt");
                 }
             }
+
+            @Nested
+            @TestMetadata("compiler/testData/diagnostics/tests/scopes/variantProjections")
+            @TestDataPath("$PROJECT_ROOT")
+            public class VariantProjections {
+                @Test
+                public void testAllFilesPresentInVariantProjections() throws Exception {
+                    KtTestUtil.assertAllTestsPresentByMetadataWithExcluded(this.getClass(), new File("compiler/testData/diagnostics/tests/scopes/variantProjections"), Pattern.compile("^(.*)\\.kts?$"), Pattern.compile("^(.+)\\.(reversed|fir|ll)\\.kts?$"), true, "multiplatform");
+                }
+
+                @Test
+                @TestMetadata("dataClassCopy.kt")
+                public void testDataClassCopy() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/scopes/variantProjections/dataClassCopy.kt");
+                }
+
+                @Test
+                @TestMetadata("interdependentStarProjections.kt")
+                public void testInterdependentStarProjections() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/scopes/variantProjections/interdependentStarProjections.kt");
+                }
+
+                @Test
+                @TestMetadata("unsafeVarianceAndCovariantProjection.kt")
+                public void testUnsafeVarianceAndCovariantProjection() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/scopes/variantProjections/unsafeVarianceAndCovariantProjection.kt");
+                }
+            }
         }
 
         @Nested

compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/FirUpperBoundViolatedHelpers.kt

@@ -21,7 +21,6 @@ import org.jetbrains.kotlin.fir.symbols.impl.FirTypeParameterSymbol
 import org.jetbrains.kotlin.fir.types.*
 import org.jetbrains.kotlin.name.StandardClassIds
 import org.jetbrains.kotlin.types.AbstractTypeChecker
-import org.jetbrains.kotlin.types.TypeApproximatorConfiguration
 import kotlin.reflect.KClass
 
 /**
@@ -88,14 +87,6 @@ private class FE10LikeConeSubstitutor(
             projection.type!!.updateNullabilityIfNeeded(type)?.withCombinedAttributesFrom(type)
                 ?: return null
 
-        if (type.isUnsafeVarianceType(useSiteSession)) {
-            useSiteSession.typeApproximator.approximateToSuperType(
-                result, TypeApproximatorConfiguration.FinalApproximationAfterResolutionAndInference
-            )?.let {
-                return it.withProjection(projection)
-            }
-        }
-
         return result.withProjection(projection)
     }
 

compiler/fir/java/src/org/jetbrains/kotlin/fir/resolve/scopes/JvmMappedScopes.kt

@@ -11,8 +11,11 @@ import org.jetbrains.kotlin.fir.declarations.FirClass
 import org.jetbrains.kotlin.fir.declarations.FirRegularClass
 import org.jetbrains.kotlin.fir.declarations.FirResolvePhase
 import org.jetbrains.kotlin.fir.declarations.utils.classId
-import org.jetbrains.kotlin.fir.resolve.*
+import org.jetbrains.kotlin.fir.resolve.ScopeSession
+import org.jetbrains.kotlin.fir.resolve.createSubstitutionForScope
+import org.jetbrains.kotlin.fir.resolve.defaultType
 import org.jetbrains.kotlin.fir.resolve.providers.symbolProvider
+import org.jetbrains.kotlin.fir.resolve.scopeSessionKey
 import org.jetbrains.kotlin.fir.resolve.substitution.substitutorByMap
 import org.jetbrains.kotlin.fir.scopes.FirContainingNamesAwareScope
 import org.jetbrains.kotlin.fir.scopes.FirTypeScope
@@ -82,7 +85,7 @@ private fun wrapSubstitutionScopeIfNeed(
         // is called on an external type, like MyMap<String, String>,
         // to determine parameter types properly (e.g. String, String instead of K, V)
         val platformTypeParameters = platformClass.typeParameters
-        val platformSubstitution = createSubstitution(platformTypeParameters, declaration.defaultType(), session)
+        val platformSubstitution = createSubstitutionForScope(platformTypeParameters, declaration.defaultType(), session)
         val substitutor = substitutorByMap(platformSubstitution, session)
         FirClassSubstitutionScope(
             session, useSiteMemberScope, PLATFORM_TYPE_PARAMETERS_SUBSTITUTION_SCOPE_KEY, substitutor,
@@ -94,4 +97,3 @@ private fun wrapSubstitutionScopeIfNeed(
 }
 
 private val PLATFORM_TYPE_PARAMETERS_SUBSTITUTION_SCOPE_KEY = scopeSessionKey<FirClassSymbol<*>, FirTypeScope>()
-

compiler/fir/providers/src/org/jetbrains/kotlin/fir/resolve/ScopeUtils.kt

@@ -119,7 +119,7 @@ private fun ConeClassLikeType.classScope(
     val substitutor = when {
         attributes.contains(CompilerConeAttributes.RawType) -> ConeRawScopeSubstitutor(useSiteSession)
         else -> substitutorByMap(
-            createSubstitution(fir.typeParameters, fullyExpandedType, useSiteSession),
+            createSubstitutionForScope(fir.typeParameters, fullyExpandedType, useSiteSession),
             useSiteSession,
         )
     }

compiler/fir/providers/src/org/jetbrains/kotlin/fir/resolve/SupertypeUtils.kt

@@ -18,10 +18,11 @@ import org.jetbrains.kotlin.fir.resolve.substitution.ConeSubstitutorByMap
 import org.jetbrains.kotlin.fir.scopes.FirScope
 import org.jetbrains.kotlin.fir.scopes.FirTypeScope
 import org.jetbrains.kotlin.fir.symbols.ConeClassLikeLookupTag
-import org.jetbrains.kotlin.fir.symbols.lazyResolveToPhase
 import org.jetbrains.kotlin.fir.symbols.impl.*
+import org.jetbrains.kotlin.fir.symbols.lazyResolveToPhase
 import org.jetbrains.kotlin.fir.types.*
-import org.jetbrains.kotlin.name.ClassId
+import org.jetbrains.kotlin.types.TypeApproximatorConfiguration
+import org.jetbrains.kotlin.types.Variance
 import org.jetbrains.kotlin.types.model.CaptureStatus
 import org.jetbrains.kotlin.utils.SmartList
 import org.jetbrains.kotlin.utils.SmartSet
@@ -178,29 +179,54 @@ inline fun <reified ID : Any, reified FS : FirScope> scopeSessionKey(): ScopeSes
 val USE_SITE = scopeSessionKey<FirClassSymbol<*>, FirTypeScope>()
 
 /* TODO REMOVE */
-fun createSubstitution(
+fun createSubstitutionForScope(
     typeParameters: List<FirTypeParameterRef>, // TODO: or really declared?
     type: ConeClassLikeType,
     session: FirSession
 ): Map<FirTypeParameterSymbol, ConeKotlinType> {
     val capturedOrType = session.typeContext.captureFromArguments(type, CaptureStatus.FROM_EXPRESSION) ?: type
-    val typeArguments = (capturedOrType as ConeClassLikeType).typeArguments
+    val capturedTypeArguments = (capturedOrType as ConeClassLikeType).typeArguments
-    return typeParameters.zip(typeArguments) { typeParameter, typeArgument ->
+
-        val typeParameterSymbol = typeParameter.symbol
+    return typeParameters.withIndex().mapNotNull { (index, typeParameter) ->
-        typeParameterSymbol to when (typeArgument) {
+        val capturedTypeArgument = capturedTypeArguments.getOrNull(index) ?: return@mapNotNull null
-            is ConeKotlinTypeProjection -> {
+        require(capturedTypeArgument is ConeKotlinType) {
-                typeArgument.type
+            "There should left no projections after capture conversion, but $capturedTypeArgument found at $index"
-            }
-            else /* StarProjection */ -> {
-                ConeTypeIntersector.intersectTypes(
-                    session.typeContext,
-                    typeParameterSymbol.resolvedBounds.map { it.coneType }
-                )
-            }
         }
+        val originalTypeArgument = type.typeArguments.getOrNull(index) ?: return@mapNotNull null
+
+        val typeParameterSymbol = typeParameter.symbol
+        val resultingArgument =
+            computeNonTrivialTypeArgumentForScopeSubstitutor(typeParameterSymbol, originalTypeArgument, session, capturedTypeArgument)
+                ?: capturedTypeArgument
+
+        typeParameterSymbol to resultingArgument
     }.toMap()
 }
 
+/**
+ * Returns null if `capturedTypeArgument` should be used
+ */
+private fun computeNonTrivialTypeArgumentForScopeSubstitutor(
+    typeParameterSymbol: FirTypeParameterSymbol,
+    originalTypeArgument: ConeTypeProjection,
+    session: FirSession,
+    capturedTypeArgument: ConeKotlinType
+): ConeKotlinType? {
+    // We don't do anything for contravariant parameters (IN), because their UnsafeVariance usages are mostly return type.
+    // And if we continue using captured types for them, they will just be approximated (as return types) as they've been before.
+    if (typeParameterSymbol.variance != Variance.OUT_VARIANCE) return null
+
+    return when (originalTypeArgument.kind) {
+        // Out<out T> is the same as Out<T>
+        ProjectionKind.OUT -> originalTypeArgument.type!!
+        // Out<*> is the same as Out<SubstitutedUpperBounds> (i.e. Out<Supertype(CapturedType(*))>)
+        ProjectionKind.STAR -> session.typeApproximator.approximateToSuperType(
+            capturedTypeArgument, TypeApproximatorConfiguration.FinalApproximationAfterResolutionAndInference
+        )
+        else -> null
+    }
+}
+
 private fun ConeClassLikeType.computePartialExpansion(
     useSiteSession: FirSession,
     supertypeSupplier: SupertypeSupplier

compiler/fir/providers/src/org/jetbrains/kotlin/fir/resolve/substitution/Substitutors.kt

@@ -16,7 +16,6 @@ import org.jetbrains.kotlin.fir.symbols.impl.FirTypeParameterSymbol
 import org.jetbrains.kotlin.fir.types.*
 import org.jetbrains.kotlin.fir.types.impl.ConeClassLikeTypeImpl
 import org.jetbrains.kotlin.name.StandardClassIds
-import org.jetbrains.kotlin.types.TypeApproximatorConfiguration
 import org.jetbrains.kotlin.types.model.TypeConstructorMarker
 import org.jetbrains.kotlin.types.model.TypeSubstitutorMarker
 import org.jetbrains.kotlin.types.model.TypeVariableMarker
@@ -204,16 +203,9 @@ class ConeSubstitutorByMap(
 
     override fun substituteType(type: ConeKotlinType): ConeKotlinType? {
         if (type !is ConeTypeParameterType) return null
-        val result =
+        return substitution[type.lookupTag.symbol].updateNullabilityIfNeeded(type)
-            substitution[type.lookupTag.symbol].updateNullabilityIfNeeded(type)
+            ?.withCombinedAttributesFrom(type)
-                ?.withCombinedAttributesFrom(type)
+            ?: return null
-                ?: return null
-        if (type.isUnsafeVarianceType(useSiteSession)) {
-            return useSiteSession.typeApproximator.approximateToSuperType(
-                result, TypeApproximatorConfiguration.FinalApproximationAfterResolutionAndInference
-            ) ?: result
-        }
-        return result
     }
 
     override fun equals(other: Any?): Boolean {

compiler/fir/providers/src/org/jetbrains/kotlin/fir/scopes/FirKotlinScopeProvider.kt

@@ -159,7 +159,7 @@ fun ConeKotlinType.scopeForSupertype(
 
 private fun substitutor(symbol: FirRegularClassSymbol, type: ConeClassLikeType, useSiteSession: FirSession): ConeSubstitutor {
     if (type.typeArguments.isEmpty()) return ConeSubstitutor.Empty
-    val originalSubstitution = createSubstitution(symbol.fir.typeParameters, type, useSiteSession)
+    val originalSubstitution = createSubstitutionForScope(symbol.fir.typeParameters, type, useSiteSession)
     return substitutorByMap(originalSubstitution, useSiteSession)
 }
 

compiler/fir/providers/src/org/jetbrains/kotlin/fir/types/TypeUtils.kt

@@ -241,11 +241,6 @@ fun FirTypeRef.isExtensionFunctionType(session: FirSession): Boolean {
     return coneTypeSafe<ConeKotlinType>()?.isExtensionFunctionType(session) == true
 }
 
-fun ConeKotlinType.isUnsafeVarianceType(session: FirSession): Boolean {
-    val type = this.coneLowerBoundIfFlexible().fullyExpandedType(session)
-    return type.attributes.unsafeVarianceType != null
-}
-
 fun ConeKotlinType.toSymbol(session: FirSession): FirClassifierSymbol<*>? {
     return (this as? ConeLookupTagBasedType)?.lookupTag?.toSymbol(session)
 }

compiler/testData/diagnostics/tests/generics/projectionsScope/unsafeVarianceInAliasedFunctionalType.fir.kt

@@ -1,11 +0,0 @@
-class Foo<out T>(val baz: Baz<T>)
-
-class Bar {
-    val foo: Foo<*> = TODO()
-
-    fun <T> bar(): Baz<T> {
-        return <!RETURN_TYPE_MISMATCH!>foo.baz<!>
-    }
-}
-
-typealias Baz<T> = (@UnsafeVariance T) -> Unit

compiler/testData/diagnostics/tests/generics/projectionsScope/unsafeVarianceInAliasedFunctionalType.kt

@@ -1,3 +1,5 @@
+// FIR_IDENTICAL
+// ISSUE: KT-54894
 class Foo<out T>(val baz: Baz<T>)
 
 class Bar {

compiler/testData/diagnostics/tests/inference/capturedTypes/capturedTypesSubstitutionIntoAbbreviation.fir.kt

@@ -25,7 +25,7 @@ fun main() {
     <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Function1<kotlin.Nothing, kotlin.Unit>")!>getTag3().action<!>
     <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Function1<kotlin.Nothing, kotlin.Unit>")!>getTag4().action<!>
     <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Function1<kotlin.Nothing, kotlin.Any?>")!>getTag5().action<!>
-    <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Function1<kotlin.Nothing, kotlin.Unit>")!>getTag6().action<!>
+    <!DEBUG_INFO_EXPRESSION_TYPE("Action<in kotlin.Any?>")!>getTag6().action<!>
-    <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Function1<kotlin.Nothing, kotlin.Unit>")!>getTag7().action<!>
+    <!DEBUG_INFO_EXPRESSION_TYPE("Action<kotlin.Any?>")!>getTag7().action<!>
-    <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Function1<kotlin.Nothing, kotlin.Any?>")!>getTag8().action<!>
+    <!DEBUG_INFO_EXPRESSION_TYPE("Action2<kotlin.Any?>")!>getTag8().action<!>
 }

compiler/testData/diagnostics/tests/scopes/variantProjections/dataClassCopy.fir.kt

@@ -0,0 +1,13 @@
+// ISSUE: KT-54764
+
+data class Out<out T>(val prop: T)
+
+fun foo(b: Out<*>) {
+    b.copy("") // error in K1, OK in K2
+}
+
+fun foo(a: Any) {
+    if (a is Out<*>) {
+        a.copy("")
+    }
+}

compiler/testData/diagnostics/tests/scopes/variantProjections/dataClassCopy.kt

@@ -0,0 +1,13 @@
+// ISSUE: KT-54764
+
+data class Out<out T>(val prop: T)
+
+fun foo(b: Out<*>) {
+    b.copy(<!TYPE_MISMATCH!>""<!>) // error in K1, OK in K2
+}
+
+fun foo(a: Any) {
+    if (a is Out<*>) {
+        <!DEBUG_INFO_SMARTCAST!>a<!>.copy("")
+    }
+}

compiler/testData/diagnostics/tests/scopes/variantProjections/interdependentStarProjections.fir.kt

@@ -0,0 +1,13 @@
+// ISSUE: KT-54764
+
+interface A<out T : B<F, E>, F, out E : B<T, F>> {
+    fun copy(t: @UnsafeVariance T, f: F, e: @UnsafeVariance E): A<T, F, E>
+}
+
+interface B<out X, out Y>
+
+fun foo(a: A<*, String, B<*, String>>, b1: B<*, String>, b2: B<*, *>, b3: B<String, B<*, String>>) {
+    <!DEBUG_INFO_EXPRESSION_TYPE("A<B<kotlin.String, B<*, kotlin.String>>, kotlin.String, B<*, kotlin.String>>")!>a.copy(<!ARGUMENT_TYPE_MISMATCH!>b2<!>, "", b1)<!>
+    <!DEBUG_INFO_EXPRESSION_TYPE("A<B<kotlin.String, B<*, kotlin.String>>, kotlin.String, B<*, kotlin.String>>")!>a.copy(<!ARGUMENT_TYPE_MISMATCH!>b1<!>, "", b1)<!>
+    <!DEBUG_INFO_EXPRESSION_TYPE("A<B<kotlin.String, B<*, kotlin.String>>, kotlin.String, B<*, kotlin.String>>")!>a.copy(b3, "", b1)<!>
+}

compiler/testData/diagnostics/tests/scopes/variantProjections/interdependentStarProjections.kt

@@ -0,0 +1,13 @@
+// ISSUE: KT-54764
+
+interface A<out T : B<F, E>, F, out E : B<T, F>> {
+    fun copy(t: @UnsafeVariance T, f: F, e: @UnsafeVariance E): A<T, F, E>
+}
+
+interface B<out X, out Y>
+
+fun foo(a: A<*, String, B<*, String>>, b1: B<*, String>, b2: B<*, *>, b3: B<String, B<*, String>>) {
+    <!DEBUG_INFO_EXPRESSION_TYPE("A<B<*, *>, kotlin.String, B<kotlin.Any?, kotlin.String>>")!>a.copy(b2, "", b1)<!>
+    <!DEBUG_INFO_EXPRESSION_TYPE("A<B<*, *>, kotlin.String, B<kotlin.Any?, kotlin.String>>")!>a.copy(b1, "", b1)<!>
+    <!DEBUG_INFO_EXPRESSION_TYPE("A<B<*, *>, kotlin.String, B<kotlin.Any?, kotlin.String>>")!>a.copy(b3, "", b1)<!>
+}

compiler/testData/diagnostics/tests/scopes/variantProjections/unsafeVarianceAndCovariantProjection.kt

@@ -0,0 +1,32 @@
+// FIR_IDENTICAL
+// ISSUE: KT-54764
+
+interface Out1<out T> {
+    fun copy(t: @UnsafeVariance T): Out1<T>
+}
+
+fun foo1(o1: Out1<*>, o2: Out1<<!REDUNDANT_PROJECTION!>out<!> Any?>, o3: Out1<Any?>) {
+    <!DEBUG_INFO_EXPRESSION_TYPE("Out1<kotlin.Any?>")!>o1.copy("")<!>
+    <!DEBUG_INFO_EXPRESSION_TYPE("Out1<kotlin.Any?>")!>o2.copy("")<!>
+    <!DEBUG_INFO_EXPRESSION_TYPE("Out1<kotlin.Any?>")!>o3.copy("")<!>
+}
+
+interface Out2<out T : CharSequence> {
+    fun copy(t: @UnsafeVariance T): Out2<T>
+}
+
+fun foo2(o1: Out2<*>, o2: Out2<<!REDUNDANT_PROJECTION!>out<!> CharSequence>, o3: Out2<CharSequence>) {
+    <!DEBUG_INFO_EXPRESSION_TYPE("Out2<kotlin.CharSequence>")!>o1.copy("")<!>
+    <!DEBUG_INFO_EXPRESSION_TYPE("Out2<kotlin.CharSequence>")!>o2.copy("")<!>
+    <!DEBUG_INFO_EXPRESSION_TYPE("Out2<kotlin.CharSequence>")!>o3.copy("")<!>
+}
+
+interface Out3<out T : Out3<T>> {
+    fun copy(t: @UnsafeVariance T): Out3<T>
+}
+
+fun foo3(o1: Out3<*>, o2: Out3<<!REDUNDANT_PROJECTION!>out<!> Out3<*>>, o3: Out3<Out3<*>>) {
+    <!DEBUG_INFO_EXPRESSION_TYPE("Out3<Out3<*>>")!>o1.copy(o1)<!>
+    <!DEBUG_INFO_EXPRESSION_TYPE("Out3<Out3<*>>")!>o2.copy(o1)<!>
+    <!DEBUG_INFO_EXPRESSION_TYPE("Out3<Out3<*>>")!>o3.copy(o1)<!>
+}

compiler/testData/ir/irText/types/typeAliasWithUnsafeVariance.fir.ir.txt

@@ -99,5 +99,5 @@ FILE fqName:<root> fileName:/typeAliasWithUnsafeVariance.kt
   FUN name:doAction visibility:public modality:FINAL <> () returnType:kotlin.Unit
     BLOCK_BODY
       TYPE_OP type=kotlin.Unit origin=IMPLICIT_COERCION_TO_UNIT typeOperand=kotlin.Unit
-        CALL 'public final fun <get-action> (): kotlin.Function1<RenderingT of <root>.Tag, kotlin.Unit> declared in <root>.Tag' type=kotlin.Function1<kotlin.Nothing, kotlin.Unit> origin=GET_PROPERTY
+        CALL 'public final fun <get-action> (): kotlin.Function1<RenderingT of <root>.Tag, kotlin.Unit> declared in <root>.Tag' type=kotlin.Function1<kotlin.Any?, kotlin.Unit> origin=GET_PROPERTY
           $this: CALL 'public final fun getTag (): <root>.Tag<*> declared in <root>' type=<root>.Tag<*> origin=null

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

@@ -28909,6 +28909,34 @@ public class DiagnosticTestGenerated extends AbstractDiagnosticTest {
                     runTest("compiler/testData/diagnostics/tests/scopes/protectedVisibility/withSmartcast.kt");
                 }
             }
+
+            @Nested
+            @TestMetadata("compiler/testData/diagnostics/tests/scopes/variantProjections")
+            @TestDataPath("$PROJECT_ROOT")
+            public class VariantProjections {
+                @Test
+                public void testAllFilesPresentInVariantProjections() throws Exception {
+                    KtTestUtil.assertAllTestsPresentByMetadataWithExcluded(this.getClass(), new File("compiler/testData/diagnostics/tests/scopes/variantProjections"), Pattern.compile("^(.*)\\.kts?$"), Pattern.compile("^(.+)\\.(reversed|fir|ll)\\.kts?$"), true);
+                }
+
+                @Test
+                @TestMetadata("dataClassCopy.kt")
+                public void testDataClassCopy() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/scopes/variantProjections/dataClassCopy.kt");
+                }
+
+                @Test
+                @TestMetadata("interdependentStarProjections.kt")
+                public void testInterdependentStarProjections() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/scopes/variantProjections/interdependentStarProjections.kt");
+                }
+
+                @Test
+                @TestMetadata("unsafeVarianceAndCovariantProjection.kt")
+                public void testUnsafeVarianceAndCovariantProjection() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/scopes/variantProjections/unsafeVarianceAndCovariantProjection.kt");
+                }
+            }
         }
 
         @Nested

compiler/tests-spec/testData/diagnostics/notLinked/dfa/pos/9.fir.kt

@@ -26,26 +26,26 @@ fun case_2(a: Out<<!REDUNDANT_PROJECTION!>out<!> Out<<!REDUNDANT_PROJECTION!>out
     if (a != null) {
         val b = <!DEBUG_INFO_EXPRESSION_TYPE("Out<out Out<out Out<out Out<out Out<out Out<out kotlin.Int?>?>?>?>?>?>? & Out<out Out<out Out<out Out<out Out<out Out<out kotlin.Int?>?>?>?>?>?>")!>a<!>.get()
         if (b != null) {
-            val c = <!DEBUG_INFO_EXPRESSION_TYPE("Out<Out<Out<Out<Out<kotlin.Any?>?>?>?>?>? & Out<Out<Out<Out<Out<kotlin.Any?>?>?>?>?>")!>b<!>.get()
+            val c = <!DEBUG_INFO_EXPRESSION_TYPE("Out<out Out<out Out<out Out<out Out<out kotlin.Int?>?>?>?>?>? & Out<out Out<out Out<out Out<out Out<out kotlin.Int?>?>?>?>?>")!>b<!>.get()
             if (c != null) {
-                val d = <!DEBUG_INFO_EXPRESSION_TYPE("Out<Out<Out<Out<kotlin.Any?>?>?>?>? & Out<Out<Out<Out<kotlin.Any?>?>?>?>")!>c<!>.get()
+                val d = <!DEBUG_INFO_EXPRESSION_TYPE("Out<out Out<out Out<out Out<out kotlin.Int?>?>?>?>? & Out<out Out<out Out<out Out<out kotlin.Int?>?>?>?>")!>c<!>.get()
                 if (d != null) {
-                    val e = <!DEBUG_INFO_EXPRESSION_TYPE("Out<Out<Out<kotlin.Any?>?>?>? & Out<Out<Out<kotlin.Any?>?>?>")!>d<!>.get()
+                    val e = <!DEBUG_INFO_EXPRESSION_TYPE("Out<out Out<out Out<out kotlin.Int?>?>?>? & Out<out Out<out Out<out kotlin.Int?>?>?>")!>d<!>.get()
                     if (e != null) {
-                        val f = <!DEBUG_INFO_EXPRESSION_TYPE("Out<Out<kotlin.Any?>?>? & Out<Out<kotlin.Any?>?>")!>e<!>.get()
+                        val f = <!DEBUG_INFO_EXPRESSION_TYPE("Out<out Out<out kotlin.Int?>?>? & Out<out Out<out kotlin.Int?>?>")!>e<!>.get()
                         if (f != null) {
-                            val g = <!DEBUG_INFO_EXPRESSION_TYPE("Out<kotlin.Any?>? & Out<kotlin.Any?>")!>f<!>.get()
+                            val g = <!DEBUG_INFO_EXPRESSION_TYPE("Out<out kotlin.Int?>? & Out<out kotlin.Int?>")!>f<!>.get()
                             if (g != null) {
-                                <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Any? & kotlin.Any")!>g<!>
+                                <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Int? & kotlin.Int")!>g<!>
-                                <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Any? & kotlin.Any")!>g<!>.equals(null)
+                                <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Int? & kotlin.Int")!>g<!>.equals(null)
-                                <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Any? & kotlin.Any")!>g<!>.propT
+                                <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Int? & kotlin.Int")!>g<!>.propT
-                                <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Any? & kotlin.Any")!>g<!>.propAny
+                                <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Int? & kotlin.Int")!>g<!>.propAny
-                                <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Any? & kotlin.Any")!>g<!>.propNullableT
+                                <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Int? & kotlin.Int")!>g<!>.propNullableT
-                                <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Any? & kotlin.Any")!>g<!>.propNullableAny
+                                <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Int? & kotlin.Int")!>g<!>.propNullableAny
-                                <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Any? & kotlin.Any")!>g<!>.funT()
+                                <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Int? & kotlin.Int")!>g<!>.funT()
-                                <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Any? & kotlin.Any")!>g<!>.funAny()
+                                <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Int? & kotlin.Int")!>g<!>.funAny()
-                                <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Any? & kotlin.Any")!>g<!>.funNullableT()
+                                <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Int? & kotlin.Int")!>g<!>.funNullableT()
-                                <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Any? & kotlin.Any")!>g<!>.funNullableAny()
+                                <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Int? & kotlin.Int")!>g<!>.funNullableAny()
                             }
                         }
                     }