From 6e98431cecdd5304cbd082ed577e0155634cdd24 Mon Sep 17 00:00:00 2001
From: Alexander T <alexander.tarasyuk@outlook.com>
Date: Tue, 26 May 2020 18:56:53 +0300
Subject: [PATCH] fix(23716): show generic type in tagged template expression

---
 src/services/symbolDisplay.ts                 |  4 +--
 ...kInfoForGenericTaggedTemplateExpression.ts | 28 +++++++++++++++++++
 2 files changed, 30 insertions(+), 2 deletions(-)
 create mode 100644 tests/cases/fourslash/quickInfoForGenericTaggedTemplateExpression.ts

diff --git a/src/services/symbolDisplay.ts b/src/services/symbolDisplay.ts
index 11f2019513..e6891bc122 100644
--- a/src/services/symbolDisplay.ts
+++ b/src/services/symbolDisplay.ts
@@ -159,14 +159,14 @@ namespace ts.SymbolDisplay {
             }
 
             // try get the call/construct signature from the type if it matches
-            let callExpressionLike: CallExpression | NewExpression | JsxOpeningLikeElement | undefined;
+            let callExpressionLike: CallExpression | NewExpression | JsxOpeningLikeElement | TaggedTemplateExpression | undefined;
             if (isCallOrNewExpression(location)) {
                 callExpressionLike = location;
             }
             else if (isCallExpressionTarget(location) || isNewExpressionTarget(location)) {
                 callExpressionLike = <CallExpression | NewExpression>location.parent;
             }
-            else if (location.parent && isJsxOpeningLikeElement(location.parent) && isFunctionLike(symbol.valueDeclaration)) {
+            else if (location.parent && (isJsxOpeningLikeElement(location.parent) || isTaggedTemplateExpression(location.parent)) && isFunctionLike(symbol.valueDeclaration)) {
                 callExpressionLike = location.parent;
             }
 
diff --git a/tests/cases/fourslash/quickInfoForGenericTaggedTemplateExpression.ts b/tests/cases/fourslash/quickInfoForGenericTaggedTemplateExpression.ts
new file mode 100644
index 0000000000..922c998435
--- /dev/null
+++ b/tests/cases/fourslash/quickInfoForGenericTaggedTemplateExpression.ts
@@ -0,0 +1,28 @@
+/// <reference path='fourslash.ts'/>
+
+////interface T1 {}
+////class T2 {}
+////type T3 = "a" | "b";
+////
+////declare function foo<T>(strings: TemplateStringsArray, ...values: T[]): void;
+////
+/////*1*/foo<number>``;
+/////*2*/foo<string | number>``;
+/////*3*/foo<{ a: number }>``;
+/////*4*/foo<T1>``;
+/////*5*/foo<T2>``;
+/////*6*/foo<T3>``;
+/////*7*/foo``;
+
+verify.quickInfoAt("1", "function foo<number>(strings: TemplateStringsArray, ...values: number[]): void");
+verify.quickInfoAt("2", "function foo<string | number>(strings: TemplateStringsArray, ...values: (string | number)[]): void");
+verify.quickInfoAt("3",
+`function foo<{
+    a: number;
+}>(strings: TemplateStringsArray, ...values: {
+    a: number;
+}[]): void`);
+verify.quickInfoAt("4", "function foo<T1>(strings: TemplateStringsArray, ...values: T1[]): void");
+verify.quickInfoAt("5", "function foo<T2>(strings: TemplateStringsArray, ...values: T2[]): void");
+verify.quickInfoAt("6", "function foo<T3>(strings: TemplateStringsArray, ...values: T3[]): void");
+verify.quickInfoAt("7", "function foo<unknown>(strings: TemplateStringsArray, ...values: unknown[]): void");