From 1cbb0bd4d39020b904e14e48b42b1c710cb4841c Mon Sep 17 00:00:00 2001
From: Jean Pierre <jeanp413@hotmail.com>
Date: Wed, 4 Aug 2021 04:00:39 -0500
Subject: [PATCH] Do not classify Infinity and NaN (#44778)

* Do not classify Infinity and NaN. Fixes #42022

* Internally expose so that the classifier can use it

* Increase the test complexity, and revert the type-checker

* Drop the -Infinity

Co-authored-by: Orta <git@orta.io>
---
 src/services/classifier2020.ts                |  6 ++-
 ...anticModernClassificationInfinityAndNaN.ts | 39 +++++++++++++++++++
 2 files changed, 44 insertions(+), 1 deletion(-)
 create mode 100644 tests/cases/fourslash/semanticModernClassificationInfinityAndNaN.ts

diff --git a/src/services/classifier2020.ts b/src/services/classifier2020.ts
index 6a61670697c..c890b3f6dbe 100644
--- a/src/services/classifier2020.ts
+++ b/src/services/classifier2020.ts
@@ -79,7 +79,7 @@ namespace ts.classifier.v2020 {
                 inJSXElement = false;
             }
 
-            if (isIdentifier(node) && !inJSXElement && !inImportClause(node)) {
+            if (isIdentifier(node) && !inJSXElement && !inImportClause(node) && !isInfinityOrNaNString(node.escapedText)) {
                 let symbol = typeChecker.getSymbolAtLocation(node);
                 if (symbol) {
                     if (symbol.flags & SymbolFlags.Alias) {
@@ -225,6 +225,10 @@ namespace ts.classifier.v2020 {
         return (isQualifiedName(node.parent) && node.parent.right === node) || (isPropertyAccessExpression(node.parent) && node.parent.name === node);
     }
 
+    function isInfinityOrNaNString(name: __String): boolean {
+        return name === "Infinity" || name === "NaN";
+    }
+
     const tokenFromDeclarationMapping = new Map<SyntaxKind, TokenType>([
         [SyntaxKind.VariableDeclaration, TokenType.variable],
         [SyntaxKind.Parameter, TokenType.parameter],
diff --git a/tests/cases/fourslash/semanticModernClassificationInfinityAndNaN.ts b/tests/cases/fourslash/semanticModernClassificationInfinityAndNaN.ts
new file mode 100644
index 00000000000..fcd508df372
--- /dev/null
+++ b/tests/cases/fourslash/semanticModernClassificationInfinityAndNaN.ts
@@ -0,0 +1,39 @@
+/// <reference path="fourslash.ts"/>
+
+//// Infinity;
+//// NaN;
+////
+////// Regular properties
+////
+////const obj1 = {
+////    Infinity: 100,
+////    NaN: 200,
+////    "-Infinity": 300
+////};
+////
+////obj1.Infinity;
+////obj1.NaN;
+////obj1["-Infinity"];
+////
+////// Shorthand properties
+////
+////const obj2 = {
+////    Infinity,
+////    NaN,
+////}
+////
+////obj2.Infinity;
+////obj2.NaN;
+
+// Basically only the obj1 and obj2 should be showing up in this list
+
+const c2 = classification("2020");
+verify.semanticClassificationsAre("2020",
+    c2.semanticToken("variable.declaration.readonly", "obj1"), 
+    c2.semanticToken("variable.readonly", "obj1"), 
+    c2.semanticToken("variable.readonly", "obj1"), 
+    c2.semanticToken("variable.readonly", "obj1"), 
+    c2.semanticToken("variable.declaration.readonly", "obj2"), 
+    c2.semanticToken("variable.readonly", "obj2"), 
+    c2.semanticToken("variable.readonly", "obj2"), 
+);
\ No newline at end of file