Declaration merging lib file's `unique symbol` with `symbol` errors

[LukeAbby]

This snippet succeeds on Strada:

interface SymbolConstructor {
    readonly toStringTag: symbol;
}

But fails on Corsa. This effects packages like @types/jquery which does this to polyfill lib.es2015.symbol.wellknown.d.ts.

Is this another intentional change à la #1192 or is this a so far unimplemented feature?

[Andarist]

This looks like an intended break. This works in Strada thanks to (code):

// TODO: If back compat with pre-3.0/4.0 libs isn't required, remove the following SymbolConstructor special case transforming `symbol` into `unique symbol`
if (type.flags & TypeFlags.ESSymbol && isGlobalSymbolConstructor(declaration.parent)) {
  type = getESSymbolLikeTypeForNode(declaration);
}