dts: don't emit type for private-identified field

Do not emit types for private-identified fields
when generating declaration files.

// example.ts
export class A {
    #foo: number;
}

// example.d.ts

export declare class A {
    #foo;
}

**This is not ideal!**

The following would be better:

// example.d.ts

export declare unique class A {
    #foo;
}

See discussion:

microsoft#33038 (comment)

Author: mheiber

src/compiler/transformers/declarations.ts

@@ -461,7 +461,7 @@ namespace ts {
             | PropertySignature;
 
         function ensureType(node: HasInferredType, type: TypeNode | undefined, ignorePrivate?: boolean): TypeNode | undefined {
-            if (!ignorePrivate && hasModifier(node, ModifierFlags.Private)) {
+            if (!ignorePrivate && hasModifier(node, ModifierFlags.Private) || isNamedDeclaration(node) && isPrivateIdentifier(node.name)) {
                 // Private nodes emit no types (except private parameter properties, whose parameter types are actually visible)
                 return;
             }
@@ -898,7 +898,7 @@ namespace ts {
                             ensureModifiers(input),
                             input.name,
                             input.questionToken,
-                            !hasModifier(input, ModifierFlags.Private) ? ensureType(input, input.type) : undefined,
+                            ensureType(input, input.type),
                             ensureNoInitializer(input)
                         ));
                     case SyntaxKind.PropertySignature:
@@ -907,7 +907,7 @@ namespace ts {
                             ensureModifiers(input),
                             input.name,
                             input.questionToken,
-                            !hasModifier(input, ModifierFlags.Private) ? ensureType(input, input.type) : undefined,
+                            ensureType(input, input.type),
                             ensureNoInitializer(input)
                         ));
                     case SyntaxKind.MethodSignature: {

tests/baselines/reference/privateNameDeclaration.js

@@ -1,15 +1,26 @@
 //// [privateNameDeclaration.ts]
-class A {
+export class A {
+    // declaration file should not include the type of #name
     #name: string;
 }
 
 
 //// [privateNameDeclaration.js]
+"use strict";
 var _name;
+exports.__esModule = true;
 var A = /** @class */ (function () {
     function A() {
+        // declaration file should not include the type of #name
         _name.set(this, void 0);
     }
     return A;
 }());
+exports.A = A;
 _name = new WeakMap();
+
+
+//// [privateNameDeclaration.d.ts]
+export declare class A {
+    #name;
+}

tests/baselines/reference/privateNameDeclaration.symbols

@@ -1,8 +1,9 @@
 === tests/cases/conformance/classes/members/privateNames/privateNameDeclaration.ts ===
-class A {
+export class A {
 >A : Symbol(A, Decl(privateNameDeclaration.ts, 0, 0))
 
+    // declaration file should not include the type of #name
     #name: string;
->#name : Symbol(A.#name, Decl(privateNameDeclaration.ts, 0, 9))
+>#name : Symbol(A.#name, Decl(privateNameDeclaration.ts, 0, 16))
 }
 

tests/baselines/reference/privateNameDeclaration.types

@@ -1,7 +1,8 @@
 === tests/cases/conformance/classes/members/privateNames/privateNameDeclaration.ts ===
-class A {
+export class A {
 >A : A
 
+    // declaration file should not include the type of #name
     #name: string;
 >#name : string
 }

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

@@ -1,3 +1,6 @@
-class A {
+// @declaration: true
+
+export class A {
+    // declaration file should not include the type of #name
     #name: string;
 }