Fix for EA-64905 - assert: TypeUtils.intersect

compiler/testData/diagnostics/tests/recovery/emptyTypeArgs.kt

@@ -0,0 +1,3 @@
+fun main(args: Array<String>) {
+    args is Array<<!SYNTAX!><!>>
+}

compiler/testData/diagnostics/tests/recovery/emptyTypeArgs.txt

@@ -0,0 +1,3 @@
+package
+
+internal fun main(/*0*/ args: kotlin.Array<kotlin.String>): kotlin.Unit

compiler/tests/org/jetbrains/kotlin/checkers/JetDiagnosticsTestGenerated.java

@@ -9372,6 +9372,12 @@ public class JetDiagnosticsTestGenerated extends AbstractJetDiagnosticsTest {
                 JetTestUtils.assertAllTestsPresentByMetadata(this.getClass(), new File("compiler/testData/diagnostics/tests/recovery"), Pattern.compile("^(.+)\\.kt$"), true);
             }
 
+            @TestMetadata("emptyTypeArgs.kt")
+            public void testEmptyTypeArgs() throws Exception {
+                String fileName = JetTestUtils.navigationMetadata("compiler/testData/diagnostics/tests/recovery/emptyTypeArgs.kt");
+                doTest(fileName);
+            }
+
             @TestMetadata("namelessInJava.kt")
             public void testNamelessInJava() throws Exception {
                 String fileName = JetTestUtils.navigationMetadata("compiler/testData/diagnostics/tests/recovery/namelessInJava.kt");

core/descriptors/src/org/jetbrains/kotlin/types/checker/JetTypeChecker.java

@@ -28,6 +28,13 @@ public class JetTypeChecker {
 
     public static final JetTypeChecker DEFAULT = new JetTypeChecker(new TypeCheckingProcedure(new TypeCheckerProcedureCallbacksImpl()));
 
+    public static final JetTypeChecker ERROR_TYPES_ARE_EQUAL_TO_ANYTHING = new JetTypeChecker(new TypeCheckingProcedure(new TypeCheckerProcedureCallbacksImpl() {
+        @Override
+        public boolean assertEqualTypes(@NotNull JetType a, @NotNull JetType b, @NotNull TypeCheckingProcedure typeCheckingProcedure) {
+            return a.isError() || b.isError() || super.assertEqualTypes(a, b, typeCheckingProcedure);
+        }
+    }));
+
     public static final JetTypeChecker FLEXIBLE_UNEQUAL_TO_INFLEXIBLE = new JetTypeChecker(new TypeCheckingProcedure(new TypeCheckerProcedureCallbacksImpl()) {
         @Override
         protected boolean heterogeneousEquivalence(JetType inflexibleType, JetType flexibleType) {

core/descriptors/src/org/jetbrains/kotlin/types/flexibleTypes.kt

@@ -79,7 +79,9 @@ fun Collection<JetType>.singleBestRepresentative(): JetType? {
         candidate ->
         this.all {
             other ->
-            candidate == other || JetTypeChecker.DEFAULT.equalTypes(candidate, other)
+            // We consider error types equal to anything here, so that intersections like
+            // {Array<String>, Array<[ERROR]>} work correctly
+            candidate == other || JetTypeChecker.ERROR_TYPES_ARE_EQUAL_TO_ANYTHING.equalTypes(candidate, other)
         }
     }
 }