change diagnostic message

Author: a-tarasyuk

src/compiler/checker.ts

@@ -34621,15 +34621,17 @@ namespace ts {
             }
 
             function checkNaNEquality(errorNode: Node | undefined, operator: SyntaxKind, left: Expression, right: Expression, leftType: Type, rightType: Type) {
-                const isLeftNaN = leftType.flags & TypeFlags.Number && isNaN(skipParentheses(left));
-                const isRightNaN = rightType.flags & TypeFlags.Number && isNaN(skipParentheses(right));
+                const isLeftNaN = (leftType.flags & TypeFlags.Number) && isNaN(skipParentheses(left));
+                const isRightNaN = (rightType.flags & TypeFlags.Number) && isNaN(skipParentheses(right));
                 if (isLeftNaN || isRightNaN) {
                     const err = error(errorNode, Diagnostics.This_condition_will_always_return_0,
                         tokenToString(operator === SyntaxKind.EqualsEqualsEqualsToken || operator === SyntaxKind.EqualsEqualsToken ? SyntaxKind.FalseKeyword : SyntaxKind.TrueKeyword));
                     if (isLeftNaN && isRightNaN) return;
+                    const operatorString = operator === SyntaxKind.ExclamationEqualsEqualsToken || operator === SyntaxKind.ExclamationEqualsToken ? tokenToString(SyntaxKind.ExclamationToken) : "";
                     const location = isLeftNaN ? right : left;
+                    const expression = skipParentheses(location);
                     addRelatedInfo(err, createDiagnosticForNode(location, Diagnostics.Did_you_mean_0,
-                        `${operator === SyntaxKind.ExclamationEqualsEqualsToken || operator === SyntaxKind.ExclamationEqualsToken ? tokenToString(SyntaxKind.ExclamationToken) : ""}Number.isNaN(${getTextOfNode(location)})`));
+                        `${operatorString}Number.isNaN(${isEntityNameExpression(expression) ? entityNameToString(expression) : "..."})`));
                 }
             }
 

tests/baselines/reference/nanEquality.errors.txt

@@ -14,9 +14,10 @@ tests/cases/compiler/nanEquality.ts(21,5): error TS2845: This condition will alw
 tests/cases/compiler/nanEquality.ts(22,5): error TS2845: This condition will always return 'true'.
 tests/cases/compiler/nanEquality.ts(24,5): error TS2845: This condition will always return 'false'.
 tests/cases/compiler/nanEquality.ts(25,5): error TS2845: This condition will always return 'true'.
+tests/cases/compiler/nanEquality.ts(29,5): error TS2845: This condition will always return 'false'.
 
 
-==== tests/cases/compiler/nanEquality.ts (16 errors) ====
+==== tests/cases/compiler/nanEquality.ts (17 errors) ====
     declare const x: number;
 
     if (x === NaN) {}
@@ -86,4 +87,11 @@ tests/cases/compiler/nanEquality.ts(25,5): error TS2845: This condition will alw
     if (NaN != NaN) {}
         ~~~~~~~~~~
 !!! error TS2845: This condition will always return 'true'.
+    
+    // ...
+    declare let y: any;
+    if (NaN === y[0][1]) {}
+        ~~~~~~~~~~~~~~~
+!!! error TS2845: This condition will always return 'false'.
+!!! related TS1369 tests/cases/compiler/nanEquality.ts:29:13: Did you mean 'Number.isNaN(...)'?
 

tests/baselines/reference/nanEquality.js

@@ -24,6 +24,10 @@ if (NaN !== NaN) {}
 
 if (NaN == NaN) {}
 if (NaN != NaN) {}
+
+// ...
+declare let y: any;
+if (NaN === y[0][1]) {}
 
 
 //// [nanEquality.js]
@@ -43,3 +47,4 @@ if (NaN === NaN) { }
 if (NaN !== NaN) { }
 if (NaN == NaN) { }
 if (NaN != NaN) { }
+if (NaN === y[0][1]) { }

tests/baselines/reference/nanEquality.symbols

@@ -66,3 +66,11 @@ if (NaN != NaN) {}
 >NaN : Symbol(NaN, Decl(lib.es5.d.ts, --, --))
 >NaN : Symbol(NaN, Decl(lib.es5.d.ts, --, --))
 
+// ...
+declare let y: any;
+>y : Symbol(y, Decl(nanEquality.ts, 27, 11))
+
+if (NaN === y[0][1]) {}
+>NaN : Symbol(NaN, Decl(lib.es5.d.ts, --, --))
+>y : Symbol(y, Decl(nanEquality.ts, 27, 11))
+

tests/baselines/reference/nanEquality.types

@@ -90,3 +90,16 @@ if (NaN != NaN) {}
 >NaN : number
 >NaN : number
 
+// ...
+declare let y: any;
+>y : any
+
+if (NaN === y[0][1]) {}
+>NaN === y[0][1] : boolean
+>NaN : number
+>y[0][1] : any
+>y[0] : any
+>y : any
+>0 : 0
+>1 : 1
+

tests/cases/compiler/nanEquality.ts

@@ -23,3 +23,7 @@ if (NaN !== NaN) {}
 
 if (NaN == NaN) {}
 if (NaN != NaN) {}
+
+// ...
+declare let y: any;
+if (NaN === y[0][1]) {}

tests/cases/fourslash/fixNaNEquality1.ts

@@ -1,9 +1,10 @@
 /// <reference path="fourslash.ts" />
 
-////if (x === NaN) {}
+////declare const x: number;
+////[|if (x === NaN) {}|]
 
 verify.codeFix({
     index: 0,
     description: "Use `Number.isNaN(x)`.",
-    newFileContent: "if (Number.isNaN(x)) {}",
+    newRangeContent: "if (Number.isNaN(x)) {}",
 });

tests/cases/fourslash/fixNaNEquality2.ts

@@ -1,9 +1,10 @@
 /// <reference path="fourslash.ts" />
 
-////if (NaN === x) {}
+////declare const x: number;
+////[|if (NaN === x) {}|]
 
 verify.codeFix({
     index: 0,
     description: "Use `Number.isNaN(x)`.",
-    newFileContent: "if (Number.isNaN(x)) {}",
+    newRangeContent: "if (Number.isNaN(x)) {}",
 });

tests/cases/fourslash/fixNaNEquality3.ts

@@ -1,9 +1,10 @@
 /// <reference path="fourslash.ts" />
 
-////if (x !== NaN) {}
+////declare const x: number;
+////[|if (x !== NaN) {}|]
 
 verify.codeFix({
     index: 0,
     description: "Use `!Number.isNaN(x)`.",
-    newFileContent: "if (!Number.isNaN(x)) {}",
+    newRangeContent: "if (!Number.isNaN(x)) {}",
 });

tests/cases/fourslash/fixNaNEquality4.ts

@@ -1,9 +1,10 @@
 /// <reference path="fourslash.ts" />
 
-////if (NaN !== x) {}
+////declare const x: number;
+////[|if (NaN !== x) {}|]
 
 verify.codeFix({
     index: 0,
     description: "Use `!Number.isNaN(x)`.",
-    newFileContent: "if (!Number.isNaN(x)) {}",
+    newRangeContent: "if (!Number.isNaN(x)) {}",
 });