[FIR] Expand type of const val in FirConstPropertyChecker

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

@@ -975,6 +975,11 @@ public class LazyBodyIsNotTouchedTilContractsPhaseTestGenerated extends Abstract
         public void testConstValWithGetterOrDelegate() throws Exception {
             runTest("compiler/fir/analysis-tests/testData/resolve/constVal/constValWithGetterOrDelegate.kt");
         }
+
+        @TestMetadata("constValWithTypealiasType.kt")
+        public void testConstValWithTypealiasType() throws Exception {
+            runTest("compiler/fir/analysis-tests/testData/resolve/constVal/constValWithTypealiasType.kt");
+        }
     }
 
     @TestMetadata("compiler/fir/analysis-tests/testData/resolve/constructors")

compiler/fir/analysis-tests/testData/resolve/constVal/constValWithTypealiasType.fir.txt

@@ -0,0 +1,4 @@
+FILE: constValWithTypealiasType.kt
+    public final typealias Foo = R|kotlin/Int|
+    public final const val x: R|Foo| = Int(10)
+        public get(): R|Foo|

compiler/fir/analysis-tests/testData/resolve/constVal/constValWithTypealiasType.kt

@@ -0,0 +1,3 @@
+typealias Foo = Int
+
+const val x: Foo = 10

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

@@ -1128,6 +1128,12 @@ public class FirDiagnosticTestGenerated extends AbstractFirDiagnosticTest {
             public void testConstValWithGetterOrDelegate() throws Exception {
                 runTest("compiler/fir/analysis-tests/testData/resolve/constVal/constValWithGetterOrDelegate.kt");
             }
+
+            @Test
+            @TestMetadata("constValWithTypealiasType.kt")
+            public void testConstValWithTypealiasType() throws Exception {
+                runTest("compiler/fir/analysis-tests/testData/resolve/constVal/constValWithTypealiasType.kt");
+            }
         }
 
         @Nested

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

@@ -1128,6 +1128,12 @@ public class FirDiagnosticsWithLightTreeTestGenerated extends AbstractFirDiagnos
             public void testConstValWithGetterOrDelegate() throws Exception {
                 runTest("compiler/fir/analysis-tests/testData/resolve/constVal/constValWithGetterOrDelegate.kt");
             }
+
+            @Test
+            @TestMetadata("constValWithTypealiasType.kt")
+            public void testConstValWithTypealiasType() throws Exception {
+                runTest("compiler/fir/analysis-tests/testData/resolve/constVal/constValWithTypealiasType.kt");
+            }
         }
 
         @Nested

compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/declaration/FirConstPropertyChecker.kt

@@ -17,6 +17,7 @@ import org.jetbrains.kotlin.fir.analysis.diagnostics.reportOn
 import org.jetbrains.kotlin.fir.declarations.FirProperty
 import org.jetbrains.kotlin.fir.declarations.FirRegularClass
 import org.jetbrains.kotlin.fir.declarations.isConst
+import org.jetbrains.kotlin.fir.resolve.fullyExpandedType
 import org.jetbrains.kotlin.fir.types.ConeClassErrorType
 import org.jetbrains.kotlin.fir.types.coneType
 import org.jetbrains.kotlin.lexer.KtTokens
@@ -55,7 +56,7 @@ object FirConstPropertyChecker : FirPropertyChecker() {
             return
         }
 
-        val type = declaration.returnTypeRef.coneType
+        val type = declaration.returnTypeRef.coneType.fullyExpandedType(context.session)
         if ((type !is ConeClassErrorType) && !type.canBeUsedForConstVal()) {
             reporter.reportOn(declaration.source, FirErrors.TYPE_CANT_BE_USED_FOR_CONST_VAL, declaration.returnTypeRef.coneType, context)
             return
@@ -65,4 +66,4 @@ object FirConstPropertyChecker : FirPropertyChecker() {
             reporter.reportOn(initializer.source, FirErrors.CONST_VAL_WITH_NON_CONST_INITIALIZER, context)
         }
     }
-}
+}

idea/idea-frontend-fir/idea-fir-low-level-api/tests/org/jetbrains/kotlin/idea/fir/low/level/api/diagnostic/compiler/based/DiagnosisCompilerFirTestdataTestGenerated.java

@@ -977,6 +977,11 @@ public class DiagnosisCompilerFirTestdataTestGenerated extends AbstractDiagnosis
             public void testConstValWithGetterOrDelegate() throws Exception {
                 runTest("compiler/fir/analysis-tests/testData/resolve/constVal/constValWithGetterOrDelegate.kt");
             }
+
+            @TestMetadata("constValWithTypealiasType.kt")
+            public void testConstValWithTypealiasType() throws Exception {
+                runTest("compiler/fir/analysis-tests/testData/resolve/constVal/constValWithTypealiasType.kt");
+            }
         }
 
         @TestMetadata("compiler/fir/analysis-tests/testData/resolve/constructors")