From 485010dd975ab9b5f59e8552cae10acd22fea08e Mon Sep 17 00:00:00 2001
From: YeonJuan <yeonjuan93@naver.com>
Date: Wed, 29 Jan 2025 16:27:02 +0900
Subject: [PATCH 1/2] fix(eslint-plugin): [no-unnecessary-template-expression]
 allow type parameter

---
 .../no-unnecessary-template-expression.ts     |  3 ++-
 ...no-unnecessary-template-expression.test.ts | 26 ++++---------------
 2 files changed, 7 insertions(+), 22 deletions(-)

diff --git a/packages/eslint-plugin/src/rules/no-unnecessary-template-expression.ts b/packages/eslint-plugin/src/rules/no-unnecessary-template-expression.ts
index 308855686d79..842f549eb34a 100644
--- a/packages/eslint-plugin/src/rules/no-unnecessary-template-expression.ts
+++ b/packages/eslint-plugin/src/rules/no-unnecessary-template-expression.ts
@@ -451,13 +451,14 @@ export default createRule<[], MessageId>({
           isTrivialInterpolation(node) &&
           !hasCommentsBetweenQuasi(node.quasis[0], node.quasis[1])
         ) {
-          const { constraintType } = getConstraintInfo(
+          const { constraintType, isTypeParameter } = getConstraintInfo(
             checker,
             services.getTypeAtLocation(node.types[0]),
           );
 
           if (
             constraintType &&
+            !isTypeParameter &&
             isUnderlyingTypeString(constraintType) &&
             !isEnumType(constraintType)
           ) {
diff --git a/packages/eslint-plugin/tests/rules/no-unnecessary-template-expression.test.ts b/packages/eslint-plugin/tests/rules/no-unnecessary-template-expression.test.ts
index 160c9114f2aa..6fa636d875fb 100644
--- a/packages/eslint-plugin/tests/rules/no-unnecessary-template-expression.test.ts
+++ b/packages/eslint-plugin/tests/rules/no-unnecessary-template-expression.test.ts
@@ -1190,6 +1190,11 @@ enum Foo {
 }
 type Bar = \`\${Foo.A}\`;
     `,
+    `
+function foo<T extends string>() {
+  const a: \`\${T}\` = 'a';
+}
+    `,
   ],
 
   invalid: [
@@ -1431,26 +1436,5 @@ enum Foo {
 type Bar = Foo.A;
       `,
     },
-    {
-      code: `
-function foo<T extends string>() {
-  const a: \`\${T}\` = 'a';
-}
-      `,
-      errors: [
-        {
-          column: 13,
-          endColumn: 17,
-          endLine: 3,
-          line: 3,
-          messageId: 'noUnnecessaryTemplateExpression',
-        },
-      ],
-      output: `
-function foo<T extends string>() {
-  const a: T = 'a';
-}
-      `,
-    },
   ],
 });

From d42f799dc9d815c43007e136d73ce50813010534 Mon Sep 17 00:00:00 2001
From: YeonJuan <yeonjuan93@naver.com>
Date: Wed, 29 Jan 2025 16:41:24 +0900
Subject: [PATCH 2/2] update

---
 .../docs/rules/no-unnecessary-template-expression.mdx          | 3 +++
 .../no-unnecessary-template-expression.shot                    | 3 +++
 .../tests/rules/no-unnecessary-template-expression.test.ts     | 1 +
 3 files changed, 7 insertions(+)

diff --git a/packages/eslint-plugin/docs/rules/no-unnecessary-template-expression.mdx b/packages/eslint-plugin/docs/rules/no-unnecessary-template-expression.mdx
index c720652ebf7a..9262d9fea9be 100644
--- a/packages/eslint-plugin/docs/rules/no-unnecessary-template-expression.mdx
+++ b/packages/eslint-plugin/docs/rules/no-unnecessary-template-expression.mdx
@@ -67,6 +67,9 @@ enum ABC {
 }
 type ABCUnion = `${ABC}`;
 
+// Interpolating type parameters is allowed.
+type TextUtil<T extends string> = `${T}`;
+
 const stringWithNumber = `1 + 1 = 2`;
 
 const stringWithBoolean = `true is true`;
diff --git a/packages/eslint-plugin/tests/docs-eslint-output-snapshots/no-unnecessary-template-expression.shot b/packages/eslint-plugin/tests/docs-eslint-output-snapshots/no-unnecessary-template-expression.shot
index 0065786d6ef9..2d5241b52e5e 100644
--- a/packages/eslint-plugin/tests/docs-eslint-output-snapshots/no-unnecessary-template-expression.shot
+++ b/packages/eslint-plugin/tests/docs-eslint-output-snapshots/no-unnecessary-template-expression.shot
@@ -60,6 +60,9 @@ enum ABC {
 }
 type ABCUnion = \`\${ABC}\`;
 
+// Interpolating type parameters is allowed.
+type TextUtil<T extends string> = \`\${T}\`;
+
 const stringWithNumber = \`1 + 1 = 2\`;
 
 const stringWithBoolean = \`true is true\`;
diff --git a/packages/eslint-plugin/tests/rules/no-unnecessary-template-expression.test.ts b/packages/eslint-plugin/tests/rules/no-unnecessary-template-expression.test.ts
index 6fa636d875fb..f60f87126f78 100644
--- a/packages/eslint-plugin/tests/rules/no-unnecessary-template-expression.test.ts
+++ b/packages/eslint-plugin/tests/rules/no-unnecessary-template-expression.test.ts
@@ -1195,6 +1195,7 @@ function foo<T extends string>() {
   const a: \`\${T}\` = 'a';
 }
     `,
+    'type T<A extends string> = `${A}`;',
   ],
 
   invalid: [