FIR: Unwrap type aliases in type arguments

compiler/fir/analysis-tests/legacy-fir-tests/tests-gen/org/jetbrains/kotlin/fir/LazyBodyIsNotTouchedTilContractsPhaseTestGenerated.java

@@ -3455,6 +3455,11 @@ public class LazyBodyIsNotTouchedTilContractsPhaseTestGenerated extends Abstract
         public void testCastToBareType() throws Exception {
             runTest("compiler/fir/analysis-tests/testData/resolve/types/castToBareType.kt");
         }
+
+        @TestMetadata("typeAliasInArguments.kt")
+        public void testTypeAliasInArguments() throws Exception {
+            runTest("compiler/fir/analysis-tests/testData/resolve/types/typeAliasInArguments.kt");
+        }
     }
 
     @TestMetadata("compiler/fir/analysis-tests/testData/resolve/visibility")

compiler/fir/analysis-tests/testData/resolve/types/typeAliasInArguments.fir.txt

@@ -0,0 +1,7 @@
+FILE: main.kt
+    public final typealias ImmutableMap<K, V> = R|MyMap<K, V>|
+    public final typealias ImmutableSet<E> = R|MySet<E>|
+    private final typealias ImmutableMultimap<K, V> = R|ImmutableMap<K, ImmutableSet<V>>|
+    private final fun <K, V> R|ImmutableMultimap<K, V>|.put(key: R|K|, value: R|V|, oldSet: R|ImmutableSet<V>|): R|ImmutableMultimap<K, V>| {
+        ^put this@R|/put|.R|SubstitutionOverride</MyMap.put: R|ft<MyMap<ft<K, K?>, ft<ImmutableSet<V>, ImmutableSet<V>?>>, MyMap<ft<K, K?>, ft<ImmutableSet<V>, ImmutableSet<V>?>>?>|>|(R|<local>/key|, R|<local>/oldSet|.R|SubstitutionOverride</MySet.add: R|ft<MySet<ft<V, V?>>, MySet<ft<V, V?>>?>|>|(R|<local>/value|))
+    }

compiler/fir/analysis-tests/testData/resolve/types/typeAliasInArguments.kt

@@ -0,0 +1,21 @@
+// FILE: MyMap.java
+
+public interface MyMap<K, V> {
+    public MyMap<K, V> put(K k, V v);
+}
+// FILE: MySet.java
+
+public interface MySet<E> {
+    public MySet<E> add(E e);
+}
+
+// FILE: main.kt
+
+typealias ImmutableMap<K, V> = MyMap<K, V>
+typealias ImmutableSet<E> = MySet<E>
+
+private typealias ImmutableMultimap<K, V> = ImmutableMap<K, ImmutableSet<V>>
+
+private fun <K, V> ImmutableMultimap<K, V>.put(key: K, value: V, oldSet: ImmutableSet<V>): ImmutableMultimap<K, V> {
+    return put(key, oldSet.add(value))
+}

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

@@ -3852,6 +3852,12 @@ public class FirDiagnosticTestGenerated extends AbstractFirDiagnosticTest {
             public void testCastToBareType() throws Exception {
                 runTest("compiler/fir/analysis-tests/testData/resolve/types/castToBareType.kt");
             }
+
+            @Test
+            @TestMetadata("typeAliasInArguments.kt")
+            public void testTypeAliasInArguments() throws Exception {
+                runTest("compiler/fir/analysis-tests/testData/resolve/types/typeAliasInArguments.kt");
+            }
         }
 
         @Nested

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

@@ -3852,6 +3852,12 @@ public class FirDiagnosticsWithLightTreeTestGenerated extends AbstractFirDiagnos
             public void testCastToBareType() throws Exception {
                 runTest("compiler/fir/analysis-tests/testData/resolve/types/castToBareType.kt");
             }
+
+            @Test
+            @TestMetadata("typeAliasInArguments.kt")
+            public void testTypeAliasInArguments() throws Exception {
+                runTest("compiler/fir/analysis-tests/testData/resolve/types/typeAliasInArguments.kt");
+            }
         }
 
         @Nested

core/compiler.common/src/org/jetbrains/kotlin/types/AbstractTypeChecker.kt

@@ -222,8 +222,8 @@ object AbstractTypeChecker {
             if (a === b) return true
 
             if (isCommonDenotableType(a) && isCommonDenotableType(b)) {
-                val refinedA = context.refineType(a)
-                val refinedB = context.refineType(b)
+                val refinedA = context.prepareType(context.refineType(a))
+                val refinedB = context.prepareType(context.refineType(b))
                 val simpleA = refinedA.lowerBoundIfFlexible()
                 if (!areEqualTypeConstructors(refinedA.typeConstructor(), refinedB.typeConstructor())) return false
                 if (simpleA.argumentsCount() == 0) {