From adf815da614ad273e8c792082c478a51e8557918 Mon Sep 17 00:00:00 2001
From: Titian Cernicova-Dragomir <tcernicovad1@bloomberg.net>
Date: Fri, 27 Sep 2024 11:06:02 +0100
Subject: [PATCH] Remove dry by fix of type widening in declaration files.

---
 src/compiler/checker.ts                       | 11 ++++------
 .../reference/ambientConstLiterals.js         |  4 ++--
 .../reference/strictFunctionTypes1.js         | 20 +------------------
 .../stringLiteralTypesOverloads02.js          |  8 ++++----
 4 files changed, 11 insertions(+), 32 deletions(-)

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 63561cbe75577..adf95d3061b3f 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -6088,16 +6088,13 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
             serializeTypeOfDeclaration(syntacticContext, declaration, symbol) {
                 // Get type of the symbol if this is the valid symbol otherwise get type at location
                 const context = syntacticContext as NodeBuilderContext;
-                let type;
-                if (symbol === undefined) {
-                    symbol ??= getSymbolOfDeclaration(declaration);
+                symbol ??= getSymbolOfDeclaration(declaration);
+                let type = context.enclosingSymbolTypes?.get(getSymbolId(symbol));
+                if (type === undefined) {
                     type = symbol && !(symbol.flags & (SymbolFlags.TypeLiteral | SymbolFlags.Signature))
-                        ? instantiateType(getTypeOfSymbol(symbol), context.mapper)
+                        ? instantiateType(getWidenedLiteralType(getTypeOfSymbol(symbol)), context.mapper)
                         : errorType;
                 }
-                else {
-                    type = context.enclosingSymbolTypes?.get(getSymbolId(symbol)) ?? getTypeOfSymbol(symbol);
-                }
                 const addUndefinedForParameter = declaration && (isParameter(declaration) || isJSDocParameterTag(declaration)) && requiresAddingImplicitUndefined(declaration, context.enclosingDeclaration);
                 if (addUndefinedForParameter) {
                     type = getOptionalType(type);
diff --git a/tests/baselines/reference/ambientConstLiterals.js b/tests/baselines/reference/ambientConstLiterals.js
index 230df0414e773..8b35d43487203 100644
--- a/tests/baselines/reference/ambientConstLiterals.js
+++ b/tests/baselines/reference/ambientConstLiterals.js
@@ -74,5 +74,5 @@ declare const c9: {
 declare const c10: number[];
 declare const c11: string;
 declare const c12: number;
-declare const c13: "abc" | "def";
-declare const c14: 123 | 456;
+declare const c13: string;
+declare const c14: number;
diff --git a/tests/baselines/reference/strictFunctionTypes1.js b/tests/baselines/reference/strictFunctionTypes1.js
index 903222409a6bc..25769522a4898 100644
--- a/tests/baselines/reference/strictFunctionTypes1.js
+++ b/tests/baselines/reference/strictFunctionTypes1.js
@@ -82,7 +82,7 @@ declare function fs(x: string): void;
 declare function fx(f: (x: "def") => void): void;
 declare const x1: (x: string) => void;
 declare const x2 = "abc";
-declare const x3: "def" | "abc";
+declare const x3: string;
 declare const x4: Func<string>;
 declare const never: never;
 declare const x10: string;
@@ -107,21 +107,3 @@ declare function coAndContraArray<T>(value: T[], func: (t: T) => void): T[];
 declare const t4: A[];
 declare const t5: B[];
 declare const t6: A[];
-
-
-!!!! File strictFunctionTypes1.d.ts differs from original emit in noCheck emit
-//// [strictFunctionTypes1.d.ts]
-===================================================================
---- Expected	The full check baseline
-+++ Actual	with noCheck set
-@@ -9,9 +9,9 @@
- declare function fs(x: string): void;
- declare function fx(f: (x: "def") => void): void;
- declare const x1: (x: string) => void;
- declare const x2 = "abc";
--declare const x3: "def" | "abc";
-+declare const x3: "abc" | "def";
- declare const x4: Func<string>;
- declare const never: never;
- declare const x10: string;
- declare const x11: "def";
diff --git a/tests/baselines/reference/stringLiteralTypesOverloads02.js b/tests/baselines/reference/stringLiteralTypesOverloads02.js
index 216a42aec80e2..cf6e285b9049b 100644
--- a/tests/baselines/reference/stringLiteralTypesOverloads02.js
+++ b/tests/baselines/reference/stringLiteralTypesOverloads02.js
@@ -104,9 +104,9 @@ declare namespace Consts1 {
 declare const string = "string";
 declare const number = "number";
 declare const boolean = "boolean";
-declare const stringOrNumber: "string" | "number";
-declare const stringOrBoolean: "string" | "boolean";
-declare const booleanOrNumber: "number" | "boolean";
-declare const stringOrBooleanOrNumber: "string" | "number" | "boolean";
+declare const stringOrNumber: string;
+declare const stringOrBoolean: string;
+declare const booleanOrNumber: string;
+declare const stringOrBooleanOrNumber: string;
 declare namespace Consts2 {
 }