fix(46433): forbid using keywords as parameter names

Author: a-tarasyuk

src/compiler/diagnosticMessages.json

@@ -1164,6 +1164,10 @@
         "category": "Error",
         "code": 1389
     },
+    "'{0}' is not allowed as a parameter name.": {
+        "category": "Error",
+        "code": 1390
+    },
     "An import alias cannot use 'import type'": {
         "category": "Error",
         "code": 1392

src/compiler/parser.ts

@@ -2611,7 +2611,10 @@ namespace ts {
                 case ParsingContext.ObjectLiteralMembers: return parseErrorAtCurrentToken(Diagnostics.Property_assignment_expected);
                 case ParsingContext.ArrayLiteralMembers: return parseErrorAtCurrentToken(Diagnostics.Expression_or_comma_expected);
                 case ParsingContext.JSDocParameters: return parseErrorAtCurrentToken(Diagnostics.Parameter_declaration_expected);
-                case ParsingContext.Parameters: return parseErrorAtCurrentToken(Diagnostics.Parameter_declaration_expected);
+                case ParsingContext.Parameters:
+                    return isKeyword(token())
+                        ? parseErrorAtCurrentToken(Diagnostics._0_is_not_allowed_as_a_parameter_name, tokenToString(token()))
+                        : parseErrorAtCurrentToken(Diagnostics.Parameter_declaration_expected);
                 case ParsingContext.TypeParameters: return parseErrorAtCurrentToken(Diagnostics.Type_parameter_declaration_expected);
                 case ParsingContext.TypeArguments: return parseErrorAtCurrentToken(Diagnostics.Type_argument_expected);
                 case ParsingContext.TupleElementTypes: return parseErrorAtCurrentToken(Diagnostics.Type_expected);

tests/baselines/reference/reservedWords2.errors.txt

@@ -33,9 +33,12 @@ tests/cases/compiler/reservedWords2.ts(10,6): error TS1359: Identifier expected.
 tests/cases/compiler/reservedWords2.ts(11,12): error TS1359: Identifier expected. 'default' is a reserved word that cannot be used here.
 tests/cases/compiler/reservedWords2.ts(12,13): error TS1359: Identifier expected. 'null' is a reserved word that cannot be used here.
 tests/cases/compiler/reservedWords2.ts(12,17): error TS1138: Parameter declaration expected.
+tests/cases/compiler/reservedWords2.ts(13,13): error TS1390: 'enum' is not allowed as a parameter name.
+tests/cases/compiler/reservedWords2.ts(13,17): error TS2567: Enum declarations can only merge with namespace or other enum declarations.
+tests/cases/compiler/reservedWords2.ts(13,17): error TS1003: Identifier expected.
 
 
-==== tests/cases/compiler/reservedWords2.ts (35 errors) ====
+==== tests/cases/compiler/reservedWords2.ts (38 errors) ====
     import while = require("dfdf");
            ~~~~~
 !!! error TS1109: Expression expected.
@@ -118,5 +121,11 @@ tests/cases/compiler/reservedWords2.ts(12,17): error TS1138: Parameter declarati
 !!! error TS1359: Identifier expected. 'null' is a reserved word that cannot be used here.
                     ~
 !!! error TS1138: Parameter declaration expected.
-    
+    function f1(enum) {}
+                ~~~~
+!!! error TS1390: 'enum' is not allowed as a parameter name.
+                    
+!!! error TS2567: Enum declarations can only merge with namespace or other enum declarations.
+                    ~
+!!! error TS1003: Identifier expected.
 

tests/baselines/reference/reservedWords2.js

@@ -11,7 +11,7 @@ var [debugger, if] = [1, 2];
 enum void {}
 function f(default: number) {}
 class C { m(null: string) {} }
-
+function f1(enum) {}
 
 
 //// [reservedWords2.js]
@@ -46,3 +46,7 @@ var C = /** @class */ (function () {
     C.prototype.m = function (, string) { };
     return C;
 }());
+function f1() { }
+(function () {
+})( || ( = {}));
+{ }

tests/baselines/reference/reservedWords2.symbols

@@ -40,4 +40,7 @@ class C { m(null: string) {} }
 > : Symbol((Missing), Decl(reservedWords2.ts, 11, 12))
 >string : Symbol(string, Decl(reservedWords2.ts, 11, 17))
 
+function f1(enum) {}
+>f1 : Symbol(f1, Decl(reservedWords2.ts, 11, 30))
+> : Symbol((Missing), Decl(reservedWords2.ts, 12, 12))
 

tests/baselines/reference/reservedWords2.types

@@ -74,4 +74,7 @@ class C { m(null: string) {} }
 > : any
 >string : any
 
+function f1(enum) {}
+>f1 : () => any
+> : (Missing)
 

tests/cases/compiler/reservedWords2.ts

@@ -10,4 +10,4 @@ var [debugger, if] = [1, 2];
 enum void {}
 function f(default: number) {}
 class C { m(null: string) {} }
-
+function f1(enum) {}