From e56d3c989e5061d7b00a64c11cce0d6cf5622e4b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Mateusz=20Burzy=C5=84ski?= <mateuszburzynski@gmail.com>
Date: Fri, 3 Nov 2023 09:44:04 +0100
Subject: [PATCH] Fixed accidental possibility to create `Infinity`/`-Infinity`
 number literal types

---
 src/compiler/checker.ts                       |  3 +++
 .../noInfinityNumberLiterals.symbols          | 18 +++++++++++++
 .../reference/noInfinityNumberLiterals.types  | 25 +++++++++++++++++++
 .../compiler/noInfinityNumberLiterals.ts      |  9 +++++++
 4 files changed, 55 insertions(+)
 create mode 100644 tests/baselines/reference/noInfinityNumberLiterals.symbols
 create mode 100644 tests/baselines/reference/noInfinityNumberLiterals.types
 create mode 100644 tests/cases/compiler/noInfinityNumberLiterals.ts

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 3ac1038a4cdbe..526a59ba70755 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -37259,6 +37259,9 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
         }
         switch (node.operand.kind) {
             case SyntaxKind.NumericLiteral:
+                if (operandType === numberType) {
+                    return numberType;
+                }
                 switch (node.operator) {
                     case SyntaxKind.MinusToken:
                         return getFreshTypeOfLiteralType(getNumberLiteralType(-(node.operand as NumericLiteral).text));
diff --git a/tests/baselines/reference/noInfinityNumberLiterals.symbols b/tests/baselines/reference/noInfinityNumberLiterals.symbols
new file mode 100644
index 0000000000000..2af43970817d7
--- /dev/null
+++ b/tests/baselines/reference/noInfinityNumberLiterals.symbols
@@ -0,0 +1,18 @@
+//// [tests/cases/compiler/noInfinityNumberLiterals.ts] ////
+
+=== noInfinityNumberLiterals.ts ===
+type PositiveInfinity = 1e999;
+>PositiveInfinity : Symbol(PositiveInfinity, Decl(noInfinityNumberLiterals.ts, 0, 0))
+
+type NegativeInfinity = -1e999;
+>NegativeInfinity : Symbol(NegativeInfinity, Decl(noInfinityNumberLiterals.ts, 0, 30), Decl(noInfinityNumberLiterals.ts, 5, 5))
+
+const positiveInfinity = 1e999;
+>positiveInfinity : Symbol(positiveInfinity, Decl(noInfinityNumberLiterals.ts, 3, 5))
+
+const positiveInfinity2 = +1e999;
+>positiveInfinity2 : Symbol(positiveInfinity2, Decl(noInfinityNumberLiterals.ts, 4, 5))
+
+const NegativeInfinity = -1e999;
+>NegativeInfinity : Symbol(NegativeInfinity, Decl(noInfinityNumberLiterals.ts, 0, 30), Decl(noInfinityNumberLiterals.ts, 5, 5))
+
diff --git a/tests/baselines/reference/noInfinityNumberLiterals.types b/tests/baselines/reference/noInfinityNumberLiterals.types
new file mode 100644
index 0000000000000..ab0632fd5f8b5
--- /dev/null
+++ b/tests/baselines/reference/noInfinityNumberLiterals.types
@@ -0,0 +1,25 @@
+//// [tests/cases/compiler/noInfinityNumberLiterals.ts] ////
+
+=== noInfinityNumberLiterals.ts ===
+type PositiveInfinity = 1e999;
+>PositiveInfinity : number
+
+type NegativeInfinity = -1e999;
+>NegativeInfinity : number
+>-1e999 : number
+>1e999 : number
+
+const positiveInfinity = 1e999;
+>positiveInfinity : number
+>1e999 : number
+
+const positiveInfinity2 = +1e999;
+>positiveInfinity2 : number
+>+1e999 : number
+>1e999 : number
+
+const NegativeInfinity = -1e999;
+>NegativeInfinity : number
+>-1e999 : number
+>1e999 : number
+
diff --git a/tests/cases/compiler/noInfinityNumberLiterals.ts b/tests/cases/compiler/noInfinityNumberLiterals.ts
new file mode 100644
index 0000000000000..0b8da1956e19a
--- /dev/null
+++ b/tests/cases/compiler/noInfinityNumberLiterals.ts
@@ -0,0 +1,9 @@
+// @strict: true
+// @noEmit: true
+
+type PositiveInfinity = 1e999;
+type NegativeInfinity = -1e999;
+
+const positiveInfinity = 1e999;
+const positiveInfinity2 = +1e999;
+const NegativeInfinity = -1e999;