Bug 1683784 - Remove extra '#' in read-only error message for SymbolCode::PrivateNameSymbol. r=mgaudet

Differential Revision: https://phabricator.services.mozilla.com/D102257

js/src/jit-test/tests/fields/bug1683784.js

@@ -0,0 +1,12 @@
+// |jit-test| --enable-private-methods;
+
+class C {
+    #x() { }
+    constructor() { this.#x = 1; }
+}
+
+try {
+    new C
+} catch (e) {
+    assertEq(e.message, "#x is read-only")
+}

js/src/vm/ToSource.cpp

@@ -70,30 +70,28 @@ static JSString* SymbolToSource(JSContext* cx, JS::Symbol* symbol) {
     return desc;
   }
 
-  JSStringBuilder buf(cx);
   if (code == SymbolCode::PrivateNameSymbol) {
     MOZ_ASSERT(desc);
-    if (!buf.append('#') || !buf.append(desc)) {
-      return nullptr;
-    }
-  } else {
-    MOZ_ASSERT(code == SymbolCode::InSymbolRegistry ||
-               code == SymbolCode::UniqueSymbol);
+    return desc;
+  }
 
-    if (code == SymbolCode::InSymbolRegistry ? !buf.append("Symbol.for(")
-                                             : !buf.append("Symbol(")) {
-      return nullptr;
-    }
-    if (desc) {
-      UniqueChars quoted = QuoteString(cx, desc, '"');
-      if (!quoted || !buf.append(quoted.get(), strlen(quoted.get()))) {
-        return nullptr;
-      }
-    }
-    if (!buf.append(')')) {
+  MOZ_ASSERT(code == SymbolCode::InSymbolRegistry ||
+             code == SymbolCode::UniqueSymbol);
+
+  JSStringBuilder buf(cx);
+  if (code == SymbolCode::InSymbolRegistry ? !buf.append("Symbol.for(")
+                                           : !buf.append("Symbol(")) {
+    return nullptr;
+  }
+  if (desc) {
+    UniqueChars quoted = QuoteString(cx, desc, '"');
+    if (!quoted || !buf.append(quoted.get(), strlen(quoted.get()))) {
       return nullptr;
     }
   }
+  if (!buf.append(')')) {
+    return nullptr;
+  }
   return buf.finishString();
 }