Correctly error on enum member values referring to identifiers shadowing Infinity and NaN

src/compiler/checker.ts

@@ -43816,11 +43816,13 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
                 return +(expr as NumericLiteral).text;
             case SyntaxKind.ParenthesizedExpression:
                 return evaluate((expr as ParenthesizedExpression).expression, location);
-            case SyntaxKind.Identifier:
-                if (isInfinityOrNaNString((expr as Identifier).escapedText)) {
-                    return +((expr as Identifier).escapedText);
+            case SyntaxKind.Identifier: {
+                const identifier = expr as Identifier;
+                if (isInfinityOrNaNString(identifier.escapedText) && (resolveEntityName(identifier, SymbolFlags.Value, /*ignoreErrors*/ true) === getGlobalSymbol(identifier.escapedText, SymbolFlags.Value, /*diagnostic*/ undefined))) {
+                    return +(identifier.escapedText);
                 }
                 // falls through
+            }
             case SyntaxKind.PropertyAccessExpression:
                 if (isEntityNameExpression(expr)) {
                     const symbol = resolveEntityName(expr, SymbolFlags.Value, /*ignoreErrors*/ true);

tests/baselines/reference/enumShadowedInfinityNaN.errors.txt

@@ -0,0 +1,25 @@
+enumShadowedInfinityNaN.ts(6,9): error TS18033: Type '{}' is not assignable to type 'number' as required for computed enum member values.
+enumShadowedInfinityNaN.ts(13,9): error TS18033: Type '{}' is not assignable to type 'number' as required for computed enum member values.
+
+
+==== enumShadowedInfinityNaN.ts (2 errors) ====
+    // https://github.com/microsoft/TypeScript/issues/54981
+
+    {
+      let Infinity = {};
+      enum En {
+        X = Infinity
+            ~~~~~~~~
+!!! error TS18033: Type '{}' is not assignable to type 'number' as required for computed enum member values.
+      }
+    }
+
+    {
+      let NaN = {};
+      enum En {
+        X = NaN
+            ~~~
+!!! error TS18033: Type '{}' is not assignable to type 'number' as required for computed enum member values.
+      }
+    }
+

tests/baselines/reference/enumShadowedInfinityNaN.js

@@ -0,0 +1,36 @@
+//// [tests/cases/conformance/enums/enumShadowedInfinityNaN.ts] ////
+
+//// [enumShadowedInfinityNaN.ts]
+// https://github.com/microsoft/TypeScript/issues/54981
+
+{
+  let Infinity = {};
+  enum En {
+    X = Infinity
+  }
+}
+
+{
+  let NaN = {};
+  enum En {
+    X = NaN
+  }
+}
+
+
+//// [enumShadowedInfinityNaN.js]
+// https://github.com/microsoft/TypeScript/issues/54981
+{
+    var Infinity_1 = {};
+    var En = void 0;
+    (function (En) {
+        En[En["X"] = Infinity_1] = "X";
+    })(En || (En = {}));
+}
+{
+    var NaN_1 = {};
+    var En = void 0;
+    (function (En) {
+        En[En["X"] = NaN_1] = "X";
+    })(En || (En = {}));
+}

tests/baselines/reference/enumShadowedInfinityNaN.symbols

@@ -0,0 +1,31 @@
+//// [tests/cases/conformance/enums/enumShadowedInfinityNaN.ts] ////
+
+=== enumShadowedInfinityNaN.ts ===
+// https://github.com/microsoft/TypeScript/issues/54981
+
+{
+  let Infinity = {};
+>Infinity : Symbol(Infinity, Decl(enumShadowedInfinityNaN.ts, 3, 5))
+
+  enum En {
+>En : Symbol(En, Decl(enumShadowedInfinityNaN.ts, 3, 20))
+
+    X = Infinity
+>X : Symbol(En.X, Decl(enumShadowedInfinityNaN.ts, 4, 11))
+>Infinity : Symbol(Infinity, Decl(enumShadowedInfinityNaN.ts, 3, 5))
+  }
+}
+
+{
+  let NaN = {};
+>NaN : Symbol(NaN, Decl(enumShadowedInfinityNaN.ts, 10, 5))
+
+  enum En {
+>En : Symbol(En, Decl(enumShadowedInfinityNaN.ts, 10, 15))
+
+    X = NaN
+>X : Symbol(En.X, Decl(enumShadowedInfinityNaN.ts, 11, 11))
+>NaN : Symbol(NaN, Decl(enumShadowedInfinityNaN.ts, 10, 5))
+  }
+}
+

tests/baselines/reference/enumShadowedInfinityNaN.types

@@ -0,0 +1,33 @@
+//// [tests/cases/conformance/enums/enumShadowedInfinityNaN.ts] ////
+
+=== enumShadowedInfinityNaN.ts ===
+// https://github.com/microsoft/TypeScript/issues/54981
+
+{
+  let Infinity = {};
+>Infinity : {}
+>{} : {}
+
+  enum En {
+>En : En
+
+    X = Infinity
+>X : En.X
+>Infinity : {}
+  }
+}
+
+{
+  let NaN = {};
+>NaN : {}
+>{} : {}
+
+  enum En {
+>En : En
+
+    X = NaN
+>X : En.X
+>NaN : {}
+  }
+}
+

tests/cases/conformance/enums/enumShadowedInfinityNaN.ts

@@ -0,0 +1,15 @@
+// https://github.com/microsoft/TypeScript/issues/54981
+
+{
+  let Infinity = {};
+  enum En {
+    X = Infinity
+  }
+}
+
+{
+  let NaN = {};
+  enum En {
+    X = NaN
+  }
+}