Formatter prints module(await (await M): S), which the parser rejects #8819

Found by adversarial experiments on semantic analysts.

What is broken

Formatting a typed first-class module pack whose operand is a nested or attributed await produces source the parser rejects.

The printer keeps the general form (module(...): module(S)) only when the packed module is a direct Pmod_constraint:
https://github.com/rescript-lang/rescript/blob/8d51b9ce7/compiler/syntax/src/res_printer.ml#L3690-L3706

Every other packed module goes through the shorthand module(<mod>: S):
https://github.com/rescript-lang/rescript/blob/8d51b9ce7/compiler/syntax/src/res_printer.ml#L3707-L3728

Pmod_await puts its operand in parentheses when the operand is another await, is attributed, or is a constraint:
https://github.com/rescript-lang/rescript/blob/8d51b9ce7/compiler/syntax/src/res_printer.ml#L6095-L6115

After await, a parenthesised module followed by : is read as a functor:
https://github.com/rescript-lang/rescript/blob/8d51b9ce7/compiler/syntax/src/res_core.ml#L441-L465
https://github.com/rescript-lang/rescript/blob/8d51b9ce7/compiler/syntax/src/res_core.ml#L6650-L6661

So module(await (await M): S) parses as await applied to a functor (await M): S => ..., and the parse fails.

Reproduction

pack.res:

module type S = {}
module M = {}
let x = (module(await (await M)): module(S))

./_build/default/compiler/bsc/rescript_compiler_main.exe -nopervasives pack.res   # exit 0, emits `let x = M;`
./_build/default/compiler/syntax/cli/res_cli.exe pack.res > out.res
cat out.res | tail -1
./_build/default/compiler/syntax/cli/res_cli.exe out.res

Observed:

let x = module(await (await M): S)

  Syntax error!
  out.res:3:23-27
  Did you forget a `)` here?

Expected: output that parses, for example let x = (module(await (await M)): module(S)).

The same happens for an attributed operand: let x = (module(await (@a M)): module(S)) formats to let x = module(await (@a M): S), which also fails to parse.

The only typed-pack fixture covers a direct constraint:
https://github.com/rescript-lang/rescript/blob/8d51b9ce7/tests/syntax_tests/data/printer/modExpr/parens.res#L6

Introduced by

23a4197 (#8738) for nested await, and ac96983 (#8735) for attributed operands. Before those changes the formatter dropped the inner await or attribute instead, so its output still parsed.

Impact

Formatting a file that compiles turns it into one that no longer parses. The next compile, or the next format, fails.