From ccfd68e365391b3f117df96792355f9c3655288c Mon Sep 17 00:00:00 2001
From: Josh Goldberg <joshuakgoldberg@outlook.com>
Date: Mon, 5 Apr 2021 00:54:19 -0400
Subject: [PATCH] fix(eslint-plugin): [restrict-plus-operands] consider
 template literal types as strings (#3234)

---
 packages/eslint-plugin/src/rules/restrict-plus-operands.ts  | 5 ++++-
 .../tests/rules/restrict-plus-operands.test.ts              | 6 ++++++
 2 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/packages/eslint-plugin/src/rules/restrict-plus-operands.ts b/packages/eslint-plugin/src/rules/restrict-plus-operands.ts
index 0edf8a37d20..0f3b07e9fb2 100644
--- a/packages/eslint-plugin/src/rules/restrict-plus-operands.ts
+++ b/packages/eslint-plugin/src/rules/restrict-plus-operands.ts
@@ -57,7 +57,10 @@ export default util.createRule<Options, MessageIds>({
       if (type.isNumberLiteral()) {
         return 'number';
       }
-      if (type.isStringLiteral()) {
+      if (
+        type.isStringLiteral() ||
+        util.isTypeFlagSet(type, ts.TypeFlags.TemplateLiteral)
+      ) {
         return 'string';
       }
       // is BigIntLiteral
diff --git a/packages/eslint-plugin/tests/rules/restrict-plus-operands.test.ts b/packages/eslint-plugin/tests/rules/restrict-plus-operands.test.ts
index daa02fa46d9..af33e3ad3db 100644
--- a/packages/eslint-plugin/tests/rules/restrict-plus-operands.test.ts
+++ b/packages/eslint-plugin/tests/rules/restrict-plus-operands.test.ts
@@ -110,6 +110,12 @@ const x = a + b;
 declare const a: 'string literal' & string;
 declare const b: string;
 const x = a + b;
+    `,
+    `
+function A(s: string) {
+  return \`a\${s}b\` as const;
+}
+const b = A('') + '!';
     `,
     {
       code: `