[FIR] Ensure qualifier resolution takes place for type aliases.

When resolving a name that is used as a receiver and all
candidates are classifier symbols, we need to perform
qualifier resolution. The code used to only do that for
regular classes, and would not perform qualifier resolution if
there was a type alias candidate.

^KT-51171 Fixed

compiler/fir/fir2ir/tests-gen/org/jetbrains/kotlin/test/runners/codegen/FirBlackBoxCodegenTestGenerated.java

@@ -40821,6 +40821,12 @@ public class FirBlackBoxCodegenTestGenerated extends AbstractFirBlackBoxCodegenT
             runTest("compiler/testData/codegen/box/regressions/kt5056.kt");
         }
 
+        @Test
+        @TestMetadata("kt51171.kt")
+        public void testKt51171() throws Exception {
+            runTest("compiler/testData/codegen/box/regressions/kt51171.kt");
+        }
+
         @Test
         @TestMetadata("kt528.kt")
         public void testKt528() throws Exception {

compiler/fir/resolve/src/org/jetbrains/kotlin/fir/FirCallResolver.kt

@@ -268,7 +268,7 @@ class FirCallResolver(
             //     A // should resolved to D.A
             //     A.B // should be resolved to A.B
             // }
-            if (!result.applicability.isSuccess || (isUsedAsReceiver && result.candidates.all { it.symbol is FirRegularClassSymbol })) {
+            if (!result.applicability.isSuccess || (isUsedAsReceiver && result.candidates.all { it.symbol is FirClassifierSymbol })) {
                 components.resolveRootPartOfQualifier(
                     callee, qualifiedAccess.source, qualifiedAccess.typeArguments, nonFatalDiagnosticFromExpression,
                 )?.let { return it }

compiler/testData/codegen/box/regressions/kt51171.kt

@@ -0,0 +1,13 @@
+// TARGET_BACKEND: JVM
+
+// FILE: Error.java
+
+public class Error {
+    static String foo() {
+        return "OK";
+    }
+}
+
+// FILE: test.kt
+
+fun box() = Error.foo()

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

@@ -40359,6 +40359,12 @@ public class BlackBoxCodegenTestGenerated extends AbstractBlackBoxCodegenTest {
             runTest("compiler/testData/codegen/box/regressions/kt5056.kt");
         }
 
+        @Test
+        @TestMetadata("kt51171.kt")
+        public void testKt51171() throws Exception {
+            runTest("compiler/testData/codegen/box/regressions/kt51171.kt");
+        }
+
         @Test
         @TestMetadata("kt528.kt")
         public void testKt528() throws Exception {

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

@@ -40821,6 +40821,12 @@ public class IrBlackBoxCodegenTestGenerated extends AbstractIrBlackBoxCodegenTes
             runTest("compiler/testData/codegen/box/regressions/kt5056.kt");
         }
 
+        @Test
+        @TestMetadata("kt51171.kt")
+        public void testKt51171() throws Exception {
+            runTest("compiler/testData/codegen/box/regressions/kt51171.kt");
+        }
+
         @Test
         @TestMetadata("kt528.kt")
         public void testKt528() throws Exception {

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

@@ -32460,6 +32460,11 @@ public class LightAnalysisModeTestGenerated extends AbstractLightAnalysisModeTes
             runTest("compiler/testData/codegen/box/regressions/kt5056.kt");
         }
 
+        @TestMetadata("kt51171.kt")
+        public void testKt51171() throws Exception {
+            runTest("compiler/testData/codegen/box/regressions/kt51171.kt");
+        }
+
         @TestMetadata("kt528.kt")
         public void testKt528() throws Exception {
             runTest("compiler/testData/codegen/box/regressions/kt528.kt");