From dde79edccd6e6ec18dcf18e35647ee1f5b7b3abe Mon Sep 17 00:00:00 2001
From: Tom <26638278+tomblind@users.noreply.github.com>
Date: Tue, 23 Jul 2019 07:08:29 -0600
Subject: [PATCH] fixed crashes from recursive base constraints fixes #680

---
 src/TSHelper.ts        |  4 ++--
 test/unit/enum.spec.ts | 24 ++++++++++++++++++++++++
 2 files changed, 26 insertions(+), 2 deletions(-)

diff --git a/src/TSHelper.ts b/src/TSHelper.ts
index 6a9dc5a32..c8d749d8a 100644
--- a/src/TSHelper.ts
+++ b/src/TSHelper.ts
@@ -135,7 +135,7 @@ export function isStaticNode(node: ts.Node): boolean {
 export function isStringType(type: ts.Type, checker: ts.TypeChecker, program: ts.Program): boolean {
     if (type.symbol) {
         const baseConstraint = checker.getBaseConstraintOfType(type);
-        if (baseConstraint) {
+        if (baseConstraint && baseConstraint !== type) {
             return isStringType(baseConstraint, checker, program);
         }
     }
@@ -158,7 +158,7 @@ export function isNumberType(type: ts.Type): boolean {
 export function isExplicitArrayType(type: ts.Type, checker: ts.TypeChecker, program: ts.Program): boolean {
     if (type.symbol) {
         const baseConstraint = checker.getBaseConstraintOfType(type);
-        if (baseConstraint) {
+        if (baseConstraint && baseConstraint !== type) {
             return isExplicitArrayType(baseConstraint, checker, program);
         }
     }
diff --git a/test/unit/enum.spec.ts b/test/unit/enum.spec.ts
index 383d9708f..bd40f2619 100644
--- a/test/unit/enum.spec.ts
+++ b/test/unit/enum.spec.ts
@@ -172,3 +172,27 @@ test("Const enum index identifier chain", () => {
 
     expect(result).toBe(4);
 });
+
+test("enum toString", () => {
+    const code = `
+        enum TestEnum {
+            A,
+            B,
+            C,
+        }
+        let test = TestEnum.A;
+        return test.toString();`;
+    expect(util.transpileAndExecute(code)).toBe(0);
+});
+
+test("enum concat", () => {
+    const code = `
+        enum TestEnum {
+            A,
+            B,
+            C,
+        }
+        let test = TestEnum.A;
+        return test + "_foobar";`;
+    expect(util.transpileAndExecute(code)).toBe("0_foobar");
+});