fix: supporting using type names as reference target as well

Author: ymc9

packages/language/src/generated/grammar.ts

@@ -956,7 +956,7 @@ export const ZModelGrammar = (): Grammar => loadedZModelGrammar ?? (loadedZModel
               "terminal": {
                 "$type": "RuleCall",
                 "rule": {
-                  "$ref": "#/rules@46"
+                  "$ref": "#/rules@47"
                 },
                 "arguments": []
               },

packages/language/src/zmodel.langium

@@ -74,7 +74,7 @@ NullExpr:
     value='null';
 
 ReferenceExpr:
-    target=[ReferenceTarget:RegularID] ('(' ReferenceArgList ')')?;
+    target=[ReferenceTarget:RegularIDWithTypeNames] ('(' ReferenceArgList ')')?;
 
 fragment ReferenceArgList:
     args+=ReferenceArg (',' args+=ReferenceArg)*;

packages/schema/tests/schema/parser.test.ts

@@ -87,6 +87,24 @@ describe('Parsing Tests', () => {
         expect((attrVal.value as ReferenceExpr).target.ref?.name).toBe('USER');
     });
 
+    it('enum fields named with type name', async () => {
+        const content = `
+            enum MyEnum {
+                DateTime
+                Int
+                String
+            }
+
+            model User {
+                id String @id
+                role MyEnum @default(DateTime)
+
+                @@allow('all', role == String)
+            }
+        `;
+        await loadModel(content);
+    });
+
     it('enum dup name resolve', async () => {
         const content = `
             datasource db {