begin update checker for private names

- [x] treat private names as unique:
    - case 1: cannot say that a variable is of a class type unless the variable points to an instance of the class
        - see [test](https://github.com/mheiber/TypeScript/tree/checker/tests/cases/conformance/classes/members/privateNames/privateNamesUnique.ts)
    - case 2: private names in class hierarchies do not conflict
        - see [test](https://github.com/mheiber/TypeScript/tree/checker/tests/cases/conformance/classes/members/privateNames/privateNamesNoConflictWhenInheriting.ts)
- [x] `#constructor` is reserved
    - see [test](https://github.com/mheiber/TypeScript/tree/checker/tests/cases/conformance/classes/members/privateNames/privateNameConstructorReserved.ts)
    - check in `bindWorker`, where every node is visited
- [x] Accessibility modifiers can't be used with private names
    - see [test](https://github.com/mheiber/TypeScript/tree/checker/tests/cases/conformance/classes/members/privateNames/privateNamesNoAccessibilityModifiers.ts)
    - implemented in `checkAccessibilityModifiers`, using `ModifierFlags.AccessibilityModifier`
- [x] `delete #foo` not allowed
- [x] Private name accesses not allowed outside of the defining class
    - see test: https://github.com/mheiber/TypeScript/tree/checker/tests/cases/conformance/classes/members/privateNames/privateNameNotAccessibleOutsideDefiningClass.ts
    - see [test](https://github.com/mheiber/TypeScript/tree/checker/tests/cases/conformance/classes/members/privateNames/privateNamesNoDelete.ts)
    - implemented in `checkDeleteExpression`
- [x] Do [the right thing](https://gist.github.com/mheiber/b6fc7adb426c2e1cdaceb5d7786fc630) for nested classes

Incorporate checker PR feedback

mv private name tests together

more checker tests for private names

update naming and cleanup for check private names

for private name support in the checker:
- make names more consistent
- remove unnecessary checks
- add utility function to public API
- other small cleanup

Move getPropertyNameForUniqueESSymbol to utility

for consistency with other calculation of
special property names (starting with __),
move the calculation of property names for
unique es symbols to `utilities.ts`.

private name tests strict+es6

Update private name tests to use 'strict'
type checking and to target es6 instead of
default. Makes the js output easier to read
and tests more surface area with other
checker features.

error message for private names in obj literals

Disallow decorating private-named properties

Disallow decorating private-named properties
because the spec is still in flux.

Signed-off-by: Max Heiber <[email protected]>

Author: Max Heiber

src/compiler/utilities.ts

@@ -1497,6 +1497,10 @@ namespace ts {
     export function nodeCanBeDecorated(node: ClassElement, parent: Node): boolean;
     export function nodeCanBeDecorated(node: Node, parent: Node, grandparent: Node): boolean;
     export function nodeCanBeDecorated(node: Node, parent?: Node, grandparent?: Node): boolean {
+        // private names cannot be used with decorators yet
+        if (isNamedDeclaration(node) && node.name.kind === SyntaxKind.PrivateName) {
+            return false;
+        }
         switch (node.kind) {
             case SyntaxKind.ClassDeclaration:
                 // classes are valid targets
@@ -1510,8 +1514,8 @@ namespace ts {
             case SyntaxKind.SetAccessor:
             case SyntaxKind.MethodDeclaration:
                 // if this method has a body and its parent is a class declaration, this is a valid target.
-                return (<FunctionLikeDeclaration>node).body !== undefined
-                    && parent!.kind === SyntaxKind.ClassDeclaration;
+                return (node as FunctionLikeDeclaration).body !== undefined
+                    && parent!.kind === SyntaxKind.ClassDeclaration
 
             case SyntaxKind.Parameter:
                 // if the parameter's parent has a body and its grandparent is a class declaration, this is a valid target;

tests/baselines/reference/privateNamesAndDecorators.errors.txt

@@ -0,0 +1,18 @@
+tests/cases/conformance/classes/members/privateNames/privateNamesAndDecorators.ts(4,5): error TS1206: Decorators are not valid here.
+tests/cases/conformance/classes/members/privateNames/privateNamesAndDecorators.ts(6,5): error TS1206: Decorators are not valid here.
+
+
+==== tests/cases/conformance/classes/members/privateNames/privateNamesAndDecorators.ts (2 errors) ====
+    declare function dec<T>(target: T): T;
+    
+    class A {
+        @dec
+        ~
+!!! error TS1206: Decorators are not valid here.
+        #foo = 1;
+        @dec
+        ~
+!!! error TS1206: Decorators are not valid here.
+        #bar(): void { }
+    }
+    

tests/baselines/reference/privateNamesAndDecorators.js

@@ -0,0 +1,19 @@
+//// [privateNamesAndDecorators.ts]
+declare function dec<T>(target: T): T;
+
+class A {
+    @dec
+    #foo = 1;
+    @dec
+    #bar(): void { }
+}
+
+
+//// [privateNamesAndDecorators.js]
+var A = /** @class */ (function () {
+    function A() {
+        this.#foo = 1;
+    }
+    A.prototype.#bar = function () { };
+    return A;
+}());

tests/baselines/reference/privateNamesAndDecorators.symbols

@@ -0,0 +1,24 @@
+=== tests/cases/conformance/classes/members/privateNames/privateNamesAndDecorators.ts ===
+declare function dec<T>(target: T): T;
+>dec : Symbol(dec, Decl(privateNamesAndDecorators.ts, 0, 0))
+>T : Symbol(T, Decl(privateNamesAndDecorators.ts, 0, 21))
+>target : Symbol(target, Decl(privateNamesAndDecorators.ts, 0, 24))
+>T : Symbol(T, Decl(privateNamesAndDecorators.ts, 0, 21))
+>T : Symbol(T, Decl(privateNamesAndDecorators.ts, 0, 21))
+
+class A {
+>A : Symbol(A, Decl(privateNamesAndDecorators.ts, 0, 38))
+
+    @dec
+>dec : Symbol(dec, Decl(privateNamesAndDecorators.ts, 0, 0))
+
+    #foo = 1;
+>#foo : Symbol(A.#foo, Decl(privateNamesAndDecorators.ts, 2, 9))
+
+    @dec
+>dec : Symbol(dec, Decl(privateNamesAndDecorators.ts, 0, 0))
+
+    #bar(): void { }
+>#bar : Symbol(A.#bar, Decl(privateNamesAndDecorators.ts, 4, 13))
+}
+

tests/baselines/reference/privateNamesAndDecorators.types

@@ -0,0 +1,22 @@
+=== tests/cases/conformance/classes/members/privateNames/privateNamesAndDecorators.ts ===
+declare function dec<T>(target: T): T;
+>dec : <T>(target: T) => T
+>target : T
+
+class A {
+>A : A
+
+    @dec
+>dec : <T>(target: T) => T
+
+    #foo = 1;
+>#foo : number
+>1 : 1
+
+    @dec
+>dec : <T>(target: T) => T
+
+    #bar(): void { }
+>#bar : () => void
+}
+

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

@@ -0,0 +1,8 @@
+declare function dec<T>(target: T): T;
+
+class A {
+    @dec
+    #foo = 1;
+    @dec
+    #bar(): void { }
+}