Fix crash for private identifier in expando assignments (#37764)

* Fix crash for private identifier in expando assignments

It does this by disallowing private identifiers from expando assignments
entirely. I haven't thought of a scenario where they make sense, but I
haven't thought about it exhaustively either.

Fixes #37356

* Update baselines

I think the new error is probably better. It's certainly different!

src/compiler/utilities.ts

@@ -2155,7 +2155,7 @@ namespace ts {
 
     /** Any series of property and element accesses. */
     export function isBindableStaticAccessExpression(node: Node, excludeThisKeyword?: boolean): node is BindableStaticAccessExpression {
-        return isPropertyAccessExpression(node) && (!excludeThisKeyword && node.expression.kind === SyntaxKind.ThisKeyword || isBindableStaticNameExpression(node.expression, /*excludeThisKeyword*/ true))
+        return isPropertyAccessExpression(node) && (!excludeThisKeyword && node.expression.kind === SyntaxKind.ThisKeyword || isIdentifier(node.name) && isBindableStaticNameExpression(node.expression, /*excludeThisKeyword*/ true))
             || isBindableStaticElementAccessExpression(node, excludeThisKeyword);
     }
 
@@ -4432,7 +4432,7 @@ namespace ts {
     }
 
     export function isPropertyAccessEntityNameExpression(node: Node): node is PropertyAccessEntityNameExpression {
-        return isPropertyAccessExpression(node) && isEntityNameExpression(node.expression);
+        return isPropertyAccessExpression(node) && isIdentifier(node.name) && isEntityNameExpression(node.expression);
     }
 
     export function tryGetPropertyAccessOrIdentifierToString(expr: Expression): string | undefined {

tests/baselines/reference/privateIdentifierExpando.js

@@ -0,0 +1,9 @@
+//// [privateIdentifierExpando.js]
+const x = {};
+x.#bar.baz = 20;
+
+
+
+
+//// [privateIdentifierExpando.d.ts]
+declare const x: {};

tests/baselines/reference/privateIdentifierExpando.symbols

@@ -0,0 +1,7 @@
+=== tests/cases/conformance/salsa/privateIdentifierExpando.js ===
+const x = {};
+>x : Symbol(x, Decl(privateIdentifierExpando.js, 0, 5))
+
+x.#bar.baz = 20;
+>x : Symbol(x, Decl(privateIdentifierExpando.js, 0, 5))
+

tests/baselines/reference/privateIdentifierExpando.types

@@ -0,0 +1,13 @@
+=== tests/cases/conformance/salsa/privateIdentifierExpando.js ===
+const x = {};
+>x : {}
+>{} : {}
+
+x.#bar.baz = 20;
+>x.#bar.baz = 20 : 20
+>x.#bar.baz : any
+>x.#bar : any
+>x : {}
+>baz : any
+>20 : 20
+

tests/baselines/reference/privateNameJsBadAssignment.errors.txt

@@ -1,13 +1,16 @@
-tests/cases/conformance/classes/members/privateNames/privateNameJsBadAssignment.js(1,9): error TS2339: Property '#nope' does not exist on type 'typeof import("tests/cases/conformance/classes/members/privateNames/privateNameJsBadAssignment")'.
+tests/cases/conformance/classes/members/privateNames/privateNameJsBadAssignment.js(1,1): error TS2304: Cannot find name 'exports'.
+tests/cases/conformance/classes/members/privateNames/privateNameJsBadAssignment.js(1,9): error TS18016: Private identifiers are not allowed outside class bodies.
 tests/cases/conformance/classes/members/privateNames/privateNameJsBadAssignment.js(3,13): error TS18016: Private identifiers are not allowed outside class bodies.
 tests/cases/conformance/classes/members/privateNames/privateNameJsBadAssignment.js(6,3): error TS2339: Property '#foo' does not exist on type 'typeof B'.
 tests/cases/conformance/classes/members/privateNames/privateNameJsBadAssignment.js(11,14): error TS2339: Property '#foo' does not exist on type 'C'.
 
 
-==== tests/cases/conformance/classes/members/privateNames/privateNameJsBadAssignment.js (4 errors) ====
+==== tests/cases/conformance/classes/members/privateNames/privateNameJsBadAssignment.js (5 errors) ====
     exports.#nope = 1;           // Error (outside class body)
+    ~~~~~~~
+!!! error TS2304: Cannot find name 'exports'.
             ~~~~~
-!!! error TS2339: Property '#nope' does not exist on type 'typeof import("tests/cases/conformance/classes/members/privateNames/privateNameJsBadAssignment")'.
+!!! error TS18016: Private identifiers are not allowed outside class bodies.
     function A() { }
     A.prototype.#no = 2;         // Error (outside class body)
                 ~~~

tests/baselines/reference/privateNameJsBadAssignment.symbols

@@ -1,7 +1,5 @@
 === tests/cases/conformance/classes/members/privateNames/privateNameJsBadAssignment.js ===
 exports.#nope = 1;           // Error (outside class body)
->exports : Symbol(#nope, Decl(privateNameJsBadAssignment.js, 0, 0))
-
 function A() { }
 >A : Symbol(A, Decl(privateNameJsBadAssignment.js, 0, 18))
 
@@ -11,10 +9,10 @@ A.prototype.#no = 2;         // Error (outside class body)
 >prototype : Symbol(Function.prototype, Decl(lib.es5.d.ts, --, --))
 
 class B {}
->B : Symbol(B, Decl(privateNameJsBadAssignment.js, 2, 20), Decl(privateNameJsBadAssignment.js, 4, 10))
+>B : Symbol(B, Decl(privateNameJsBadAssignment.js, 2, 20))
 
 B.#foo = 3;                  // Error (outside class body)
->B : Symbol(B, Decl(privateNameJsBadAssignment.js, 2, 20), Decl(privateNameJsBadAssignment.js, 4, 10))
+>B : Symbol(B, Decl(privateNameJsBadAssignment.js, 2, 20))
 
 class C {
 >C : Symbol(C, Decl(privateNameJsBadAssignment.js, 5, 11))

tests/baselines/reference/privateNameJsBadAssignment.types

@@ -2,7 +2,7 @@
 exports.#nope = 1;           // Error (outside class body)
 >exports.#nope = 1 : 1
 >exports.#nope : any
->exports : typeof import("tests/cases/conformance/classes/members/privateNames/privateNameJsBadAssignment")
+>exports : any
 >1 : 1
 
 function A() { }

tests/cases/conformance/salsa/privateIdentifierExpando.ts

@@ -0,0 +1,8 @@
+// @allowJs: true
+// @checkJs: true
+// @declaration: true
+// @emitDeclarationOnly: true
+// @Filename: privateIdentifierExpando.js
+
+const x = {};
+x.#bar.baz = 20;