Improve escape sequence handling in private names

src/compiler/parser.ts

@@ -2281,7 +2281,7 @@ namespace ts {
 
         function parsePrivateIdentifier(): PrivateIdentifier {
             const pos = getNodePos();
-            const node = factory.createPrivateIdentifier(internPrivateIdentifier(scanner.getTokenText()));
+            const node = factory.createPrivateIdentifier(internPrivateIdentifier(scanner.getTokenValue()));
             nextToken();
             return finishNode(node, pos);
         }

src/compiler/scanner.ts

@@ -2052,12 +2052,38 @@ namespace ts {
                             return token = SyntaxKind.Unknown;
                         }
 
-                        if (isIdentifierStart(codePointAt(text, pos + 1), languageVersion)) {
+                        const charAfterHash = codePointAt(text, pos + 1);
+                        if (charAfterHash === CharacterCodes.backslash) {
                             pos++;
-                            scanIdentifier(codePointAt(text, pos), languageVersion);
+                            const extendedCookedChar = peekExtendedUnicodeEscape();
+                            if (extendedCookedChar >= 0 && isIdentifierStart(extendedCookedChar, languageVersion)) {
+                                pos += 3;
+                                tokenFlags |= TokenFlags.ExtendedUnicodeEscape;
+                                tokenValue = "#" + scanExtendedUnicodeEscape() + scanIdentifierParts();
+                                return token = SyntaxKind.PrivateIdentifier;
+                            }
+
+                            const cookedChar = peekUnicodeEscape();
+                            if (cookedChar >= 0 && isIdentifierStart(cookedChar, languageVersion)) {
+                                pos += 6;
+                                tokenFlags |= TokenFlags.UnicodeEscape;
+                                tokenValue = "#" + String.fromCharCode(cookedChar) + scanIdentifierParts();
+                                return token = SyntaxKind.PrivateIdentifier;
+                            }
+                            pos--;
+                        }
+
+                        if (isIdentifierStart(charAfterHash, languageVersion)) {
+                            pos++;
+                            // We're relying on scanIdentifier's behavior and adjusting the token kind after the fact.
+                            // Notably absent from this block is the fact that calling a function named "scanIdentifier",
+                            // but identifiers don't include '#', and that function doesn't deal with it at all.
+                            // This works because 'scanIdentifier' tries to reuse source characters and builds up substrings;
+                            // however, it starts at the 'tokenPos' which includes the '#', and will "accidentally" prepend the '#' for us.
+                            scanIdentifier(charAfterHash, languageVersion);
                         }
                         else {
-                            tokenValue = String.fromCharCode(codePointAt(text, pos));
+                            tokenValue = "#";
                             error(Diagnostics.Invalid_character, pos++, charSize(ch));
                         }
                         return token = SyntaxKind.PrivateIdentifier;

tests/baselines/reference/privateNamesEscapeSequences01(target=es2015).js

@@ -0,0 +1,215 @@
+//// [tests/cases/conformance/classes/members/privateNames/privateNamesEscapeSequences01.ts] ////
+
+//// [IdentifierNameWithEscape1.ts]
+export class IdentifierNameWithEscape1 {
+    \u0078: number;
+
+    constructor() {
+        this.\u0078 = 0;
+    }
+
+    doThing() {
+        this.x = 42;
+    }
+}
+
+//// [IdentifierNameWithEscape2.ts]
+export class IdentifierNameWithEscape2 {
+    x\u0078: number;
+
+    constructor() {
+        this.x\u0078 = 0;
+    }
+
+    doThing() {
+        this.xx = 42;
+    }
+}
+
+//// [IdentifierNameWithExtendedEscape1.ts]
+export class IdentifierNameWithExtendedEscape1 {
+    \u{78}: number;
+
+    constructor() {
+        this.\u{78} = 0;
+    }
+
+    doThing() {
+        this.x = 42;
+    }
+}
+
+//// [IdentifierNameWithExtendedEscape2.ts]
+export class IdentifierNameWithExtendedEscape2 {
+    x\u{78}: number;
+
+    constructor() {
+        this.x\u{78} = 0;
+    }
+
+    doThing() {
+        this.xx = 42;
+    }
+}
+
+//// [PrivateIdentifierNameWithEscape1.ts]
+export class PrivateIdentifierWithEscape1 {
+    #\u0078: number;
+
+    constructor() {
+        this.#\u0078 = 0;
+    }
+
+    doThing() {
+        this.#x = 42;
+    }
+}
+
+//// [PrivateIdentifierNameWithEscape2.ts]
+export class PrivateIdentifierWithEscape2 {
+    #x\u0078: number;
+
+    constructor() {
+        this.#x\u0078 = 0;
+    }
+
+    doThing() {
+        this.#xx = 42;
+    }
+}
+
+//// [PrivateIdentifierNameWithExtendedEscape1.ts]
+export class PrivateIdentifierWithExtendedEscape1 {
+    #\u{78}: number;
+
+    constructor() {
+        this.#\u{78} = 0;
+    }
+
+    doThing() {
+        this.#x = 42;
+    }
+}
+
+//// [PrivateIdentifierNameWithExtendedEscape2.ts]
+export class PrivateIdentifierWithExtendedEscape2 {
+    #x\u{78}: number;
+
+    constructor() {
+        this.#x\u{78} = 0;
+    }
+
+    doThing() {
+        this.#xx = 42;
+    }
+}
+
+
+//// [IdentifierNameWithEscape1.js]
+export class IdentifierNameWithEscape1 {
+    constructor() {
+        this.\u0078 = 0;
+    }
+    doThing() {
+        this.x = 42;
+    }
+}
+//// [IdentifierNameWithEscape2.js]
+export class IdentifierNameWithEscape2 {
+    constructor() {
+        this.x\u0078 = 0;
+    }
+    doThing() {
+        this.xx = 42;
+    }
+}
+//// [IdentifierNameWithExtendedEscape1.js]
+export class IdentifierNameWithExtendedEscape1 {
+    constructor() {
+        this.\u{78} = 0;
+    }
+    doThing() {
+        this.x = 42;
+    }
+}
+//// [IdentifierNameWithExtendedEscape2.js]
+export class IdentifierNameWithExtendedEscape2 {
+    constructor() {
+        this.x\u{78} = 0;
+    }
+    doThing() {
+        this.xx = 42;
+    }
+}
+//// [PrivateIdentifierNameWithEscape1.js]
+var __classPrivateFieldSet = (this && this.__classPrivateFieldSet) || function (receiver, state, value, kind, f) {
+    if (kind === "m") throw new TypeError("Private method is not writable");
+    if (kind === "a" && !f) throw new TypeError("Private accessor was defined without a setter");
+    if (typeof state === "function" ? receiver !== state || !f : !state.has(receiver)) throw new TypeError("Cannot write private member to an object whose class did not declare it");
+    return (kind === "a" ? f.call(receiver, value) : f ? f.value = value : state.set(receiver, value)), value;
+};
+var _PrivateIdentifierWithEscape1_x;
+export class PrivateIdentifierWithEscape1 {
+    constructor() {
+        _PrivateIdentifierWithEscape1_x.set(this, void 0);
+        __classPrivateFieldSet(this, _PrivateIdentifierWithEscape1_x, 0, "f");
+    }
+    doThing() {
+        __classPrivateFieldSet(this, _PrivateIdentifierWithEscape1_x, 42, "f");
+    }
+}
+_PrivateIdentifierWithEscape1_x = new WeakMap();
+//// [PrivateIdentifierNameWithEscape2.js]
+var __classPrivateFieldSet = (this && this.__classPrivateFieldSet) || function (receiver, state, value, kind, f) {
+    if (kind === "m") throw new TypeError("Private method is not writable");
+    if (kind === "a" && !f) throw new TypeError("Private accessor was defined without a setter");
+    if (typeof state === "function" ? receiver !== state || !f : !state.has(receiver)) throw new TypeError("Cannot write private member to an object whose class did not declare it");
+    return (kind === "a" ? f.call(receiver, value) : f ? f.value = value : state.set(receiver, value)), value;
+};
+var _PrivateIdentifierWithEscape2_xx;
+export class PrivateIdentifierWithEscape2 {
+    constructor() {
+        _PrivateIdentifierWithEscape2_xx.set(this, void 0);
+        __classPrivateFieldSet(this, _PrivateIdentifierWithEscape2_xx, 0, "f");
+    }
+    doThing() {
+        __classPrivateFieldSet(this, _PrivateIdentifierWithEscape2_xx, 42, "f");
+    }
+}
+_PrivateIdentifierWithEscape2_xx = new WeakMap();
+//// [PrivateIdentifierNameWithExtendedEscape1.js]
+var __classPrivateFieldSet = (this && this.__classPrivateFieldSet) || function (receiver, state, value, kind, f) {
+    if (kind === "m") throw new TypeError("Private method is not writable");
+    if (kind === "a" && !f) throw new TypeError("Private accessor was defined without a setter");
+    if (typeof state === "function" ? receiver !== state || !f : !state.has(receiver)) throw new TypeError("Cannot write private member to an object whose class did not declare it");
+    return (kind === "a" ? f.call(receiver, value) : f ? f.value = value : state.set(receiver, value)), value;
+};
+var _PrivateIdentifierWithExtendedEscape1_x;
+export class PrivateIdentifierWithExtendedEscape1 {
+    constructor() {
+        _PrivateIdentifierWithExtendedEscape1_x.set(this, void 0);
+        __classPrivateFieldSet(this, _PrivateIdentifierWithExtendedEscape1_x, 0, "f");
+    }
+    doThing() {
+        __classPrivateFieldSet(this, _PrivateIdentifierWithExtendedEscape1_x, 42, "f");
+    }
+}
+_PrivateIdentifierWithExtendedEscape1_x = new WeakMap();
+//// [PrivateIdentifierNameWithExtendedEscape2.js]
+var __classPrivateFieldSet = (this && this.__classPrivateFieldSet) || function (receiver, state, value, kind, f) {
+    if (kind === "m") throw new TypeError("Private method is not writable");
+    if (kind === "a" && !f) throw new TypeError("Private accessor was defined without a setter");
+    if (typeof state === "function" ? receiver !== state || !f : !state.has(receiver)) throw new TypeError("Cannot write private member to an object whose class did not declare it");
+    return (kind === "a" ? f.call(receiver, value) : f ? f.value = value : state.set(receiver, value)), value;
+};
+var _PrivateIdentifierWithExtendedEscape2_xx;
+export class PrivateIdentifierWithExtendedEscape2 {
+    constructor() {
+        _PrivateIdentifierWithExtendedEscape2_xx.set(this, void 0);
+        __classPrivateFieldSet(this, _PrivateIdentifierWithExtendedEscape2_xx, 0, "f");
+    }
+    doThing() {
+        __classPrivateFieldSet(this, _PrivateIdentifierWithExtendedEscape2_xx, 42, "f");
+    }
+}
+_PrivateIdentifierWithExtendedEscape2_xx = new WeakMap();