Disallow 'declare' modifier on private named properties (#36381)

Fixes: #36345

Author: ajafff

src/compiler/checker.ts

@@ -35350,6 +35350,9 @@ namespace ts {
                                 return grammarErrorOnNode(modifier, Diagnostics._0_modifier_must_precede_1_modifier, text, "abstract");
                             }
                         }
+                        else if (isPrivateIdentifierPropertyDeclaration(node)) {
+                            return grammarErrorOnNode(modifier, Diagnostics.An_accessibility_modifier_cannot_be_used_with_a_private_identifier);
+                        }
                         flags |= modifierToFlag(modifier.kind);
                         break;
 
@@ -35436,6 +35439,9 @@ namespace ts {
                         else if ((node.parent.flags & NodeFlags.Ambient) && node.parent.kind === SyntaxKind.ModuleBlock) {
                             return grammarErrorOnNode(modifier, Diagnostics.A_declare_modifier_cannot_be_used_in_an_already_ambient_context);
                         }
+                        else if (isPrivateIdentifierPropertyDeclaration(node)) {
+                            return grammarErrorOnNode(modifier, Diagnostics._0_modifier_cannot_be_used_with_a_private_identifier, "declare");
+                        }
                         flags |= ModifierFlags.Ambient;
                         lastDeclare = modifier;
                         break;
@@ -35462,7 +35468,7 @@ namespace ts {
                             }
                         }
                         if (isNamedDeclaration(node) && node.name.kind === SyntaxKind.PrivateIdentifier) {
-                            return grammarErrorOnNode(node, Diagnostics._0_modifier_cannot_be_used_with_a_private_identifier, "abstract");
+                            return grammarErrorOnNode(modifier, Diagnostics._0_modifier_cannot_be_used_with_a_private_identifier, "abstract");
                         }
 
                         flags |= ModifierFlags.Abstract;
@@ -35508,9 +35514,6 @@ namespace ts {
             else if (node.kind === SyntaxKind.Parameter && (flags & ModifierFlags.ParameterPropertyModifier) && (<ParameterDeclaration>node).dotDotDotToken) {
                 return grammarErrorOnNode(node, Diagnostics.A_parameter_property_cannot_be_declared_using_a_rest_parameter);
             }
-            else if (isNamedDeclaration(node) && (flags & ModifierFlags.AccessibilityModifier) && node.name.kind === SyntaxKind.PrivateIdentifier) {
-                return grammarErrorOnNode(node, Diagnostics.An_accessibility_modifier_cannot_be_used_with_a_private_identifier);
-            }
             if (flags & ModifierFlags.Async) {
                 return checkGrammarAsyncModifier(node, lastAsync!);
             }

tests/baselines/reference/privateNamesIncompatibleModifiers.errors.txt

@@ -1,26 +1,30 @@
-tests/cases/conformance/classes/members/privateNames/privateNamesIncompatibleModifiers.ts(2,12): error TS18010: An accessibility modifier cannot be used with a private identifier.
-tests/cases/conformance/classes/members/privateNames/privateNamesIncompatibleModifiers.ts(3,13): error TS18010: An accessibility modifier cannot be used with a private identifier.
-tests/cases/conformance/classes/members/privateNames/privateNamesIncompatibleModifiers.ts(4,15): error TS18010: An accessibility modifier cannot be used with a private identifier.
-tests/cases/conformance/classes/members/privateNames/privateNamesIncompatibleModifiers.ts(9,14): error TS18019: 'abstract' modifier cannot be used with a private identifier
+tests/cases/conformance/classes/members/privateNames/privateNamesIncompatibleModifiers.ts(2,5): error TS18010: An accessibility modifier cannot be used with a private identifier.
+tests/cases/conformance/classes/members/privateNames/privateNamesIncompatibleModifiers.ts(3,5): error TS18010: An accessibility modifier cannot be used with a private identifier.
+tests/cases/conformance/classes/members/privateNames/privateNamesIncompatibleModifiers.ts(4,5): error TS18010: An accessibility modifier cannot be used with a private identifier.
+tests/cases/conformance/classes/members/privateNames/privateNamesIncompatibleModifiers.ts(6,5): error TS18019: 'declare' modifier cannot be used with a private identifier
+tests/cases/conformance/classes/members/privateNames/privateNamesIncompatibleModifiers.ts(10,5): error TS18019: 'abstract' modifier cannot be used with a private identifier
 
 
-==== tests/cases/conformance/classes/members/privateNames/privateNamesIncompatibleModifiers.ts (4 errors) ====
+==== tests/cases/conformance/classes/members/privateNames/privateNamesIncompatibleModifiers.ts (5 errors) ====
     class A {
         public #foo = 3;         // Error
-               ~~~~
+        ~~~~~~
 !!! error TS18010: An accessibility modifier cannot be used with a private identifier.
         private #bar = 3;        // Error
-                ~~~~
+        ~~~~~~~
 !!! error TS18010: An accessibility modifier cannot be used with a private identifier.
         protected #baz = 3;      // Error
-                  ~~~~
+        ~~~~~~~~~
 !!! error TS18010: An accessibility modifier cannot be used with a private identifier.
         readonly #qux = 3;       // OK
+        declare #what: number;   // Error
+        ~~~~~~~
+!!! error TS18019: 'declare' modifier cannot be used with a private identifier
     }
 
     abstract class B {
         abstract #quux = 3;      // Error
-                 ~~~~~
+        ~~~~~~~~
 !!! error TS18019: 'abstract' modifier cannot be used with a private identifier
     }
 

tests/baselines/reference/privateNamesIncompatibleModifiers.js

@@ -4,6 +4,7 @@ class A {
     private #bar = 3;        // Error
     protected #baz = 3;      // Error
     readonly #qux = 3;       // OK
+    declare #what: number;   // Error
 }
 
 abstract class B {

tests/baselines/reference/privateNamesIncompatibleModifiers.symbols

@@ -13,12 +13,15 @@ class A {
 
     readonly #qux = 3;       // OK
 >#qux : Symbol(A.#qux, Decl(privateNamesIncompatibleModifiers.ts, 3, 23))
+
+    declare #what: number;   // Error
+>#what : Symbol(A.#what, Decl(privateNamesIncompatibleModifiers.ts, 4, 22))
 }
 
 abstract class B {
->B : Symbol(B, Decl(privateNamesIncompatibleModifiers.ts, 5, 1))
+>B : Symbol(B, Decl(privateNamesIncompatibleModifiers.ts, 6, 1))
 
     abstract #quux = 3;      // Error
->#quux : Symbol(B.#quux, Decl(privateNamesIncompatibleModifiers.ts, 7, 18))
+>#quux : Symbol(B.#quux, Decl(privateNamesIncompatibleModifiers.ts, 8, 18))
 }
 

tests/baselines/reference/privateNamesIncompatibleModifiers.types

@@ -17,6 +17,9 @@ class A {
     readonly #qux = 3;       // OK
 >#qux : 3
 >3 : 3
+
+    declare #what: number;   // Error
+>#what : number
 }
 
 abstract class B {

tests/cases/conformance/classes/members/privateNames/privateNamesIncompatibleModifiers.ts

@@ -6,6 +6,7 @@ class A {
     private #bar = 3;        // Error
     protected #baz = 3;      // Error
     readonly #qux = 3;       // OK
+    declare #what: number;   // Error
 }
 
 abstract class B {