fix: Disallow type recursion during type declaration

src/parser.ts

@@ -3478,6 +3478,28 @@ export class Parser extends DiagnosticEmitter {
     return null;
   }
 
+  private checkRecurseDefinitionForType(identifierName: string, type: TypeNode): bool {
+    switch (type.kind) {
+      case NodeKind.NAMEDTYPE:
+        return (<NamedTypeNode>type).name.identifier.text == identifierName;
+
+      case NodeKind.FUNCTIONTYPE: {
+        let fnType = <FunctionTypeNode>type;
+        if (this.checkRecurseDefinitionForType(identifierName, fnType.returnType)) {
+          return true;
+        }
+        let params = fnType.parameters;
+        for (let i = 0, k = params.length; i < k; i++) {
+          if (this.checkRecurseDefinitionForType(identifierName, params[i].type)) {
+            return true;
+          }
+        }
+        break;
+      }
+    }
+    return false;
+  }
+
   parseTypeDeclaration(
     tn: Tokenizer,
     flags: CommonFlags,
@@ -3499,6 +3521,13 @@ export class Parser extends DiagnosticEmitter {
         tn.skip(Token.BAR);
         let type = this.parseType(tn);
         if (!type) return null;
+        if (this.checkRecurseDefinitionForType(name.text, type)) {
+          this.error(
+            DiagnosticCode.Not_implemented_0,
+            tn.range(), "recursion in type aliases"
+          );
+          return null;
+        }
         let ret = Node.createTypeDeclaration(
           name,
           decorators,

tests/parser/type.ts

@@ -6,3 +6,9 @@ export type uint64_t = u64;
 export type T1 = | int32_t;
 export type T2 =
   | int32_t;
+
+// disallow type recursion
+export type T3 = T3 | null;
+export type T4 = (x: T4) => i32;
+export type T5 = () => T5;
+export type T6<T> = () => T6<T>;

tests/parser/type.ts.fixture.ts

@@ -3,3 +3,7 @@ type int32_t = i32;
 export type uint64_t = u64;
 export type T1 = int32_t;
 export type T2 = int32_t;
+// ERROR 100: "Not implemented: recursion in type aliases" in type.ts(11,23+4)
+// ERROR 100: "Not implemented: recursion in type aliases" in type.ts(12,29+3)
+// ERROR 100: "Not implemented: recursion in type aliases" in type.ts(13,24+2)
+// ERROR 100: "Not implemented: recursion in type aliases" in type.ts(14,31+1)