Migrate format_args!() lints to to ast::FormatArgs

[m-ou-se]

Now that rust-lang/rust#106745 is merged, Clippy has access to the original parsed/processed format_args!() invocation. This hopefully means that Clippy no longer needs to do anything that depends on the exact expansion of format_args!() and implementation details of fmt::Arguments (which will undergo changes in the (near!) future).

Details:

As of rust-lang/rust#106745, the format_args!() builtin macro expands to a special ast::FormatArgs AST node, which contains nothing that is specific to the standard library's fmt::Arguments implementation. During AST lowering, this node is expanded into HIR that is specific to how fmt::Arguments is implemented, and will change in the (near) future.)

Clippy's format_args lints are currently done in late passes that use the HIR. They should be changed to use the information from ast::FormatArgs instead. (Ideally by making them early passes, but that might not always be possible.)

This is part of rust-lang/rust#99012

---

Lints to migrate:

• ManualAssert - MANUAL_ASSERT: Don't depend on FormatArgsExpn in ManualAssert. #10276
• Write: Migrate write.rs to rustc_ast::FormatArgs #10275
  • PRINT_WITH_NEWLINE
  • PRINTLN_EMPTY_STRING
  • PRINT_STDOUT
  • PRINT_STDERR
  • USE_DEBUG
  • PRINT_LITERAL
  • WRITE_WITH_NEWLINE
  • WRITELN_EMPTY_STRING
  • WRITE_LITERAL
• FormatArgs: Migrate format_args.rs to rustc_ast::FormatArgs #10484
  • FORMAT_IN_FORMAT_ARGS
  • TO_STRING_IN_FORMAT_ARGS
  • UNINLINED_FORMAT_ARGS
  • UNUSED_FORMAT_SPECS
• Replace remaining usage of FormatArgsExpn #10561
  • FormatImpl
    • RECURSIVE_FORMAT_IMPL
    • PRINT_IN_FORMAT_IMPL
  • ExplicitWrite - EXPLICIT_WRITE
  • UselessFormat - USELESS_FORMAT
  • Methods - EXPECT_FUN_CALL
  • PanicExpn::Format

[m-ou-se]

cc @Alexendoo @nyurik

[Alexendoo]

Nice to see it merged, I'll take a look some time in the next few days

[nyurik]

Congratulations on merging!!! It only took 2 (?) weeks - kinda fast :) I would be very happy to participate, but don't have as good of the AST/HIR understanding as @Alexendoo, but will be happy to review and participate as much as possible.

[m-ou-se]

I've added a to do list above with the list of lints to migrate.

I'll see if I can migrate some of them soon, because this issue is now blocking rust-lang/rust#106824

[Alexendoo]

I've got write.rs mostly done, which is

PRINT_WITH_NEWLINE,
PRINTLN_EMPTY_STRING,
PRINT_STDOUT,
PRINT_STDERR,
USE_DEBUG,
PRINT_LITERAL,
WRITE_WITH_NEWLINE,
WRITELN_EMPTY_STRING,
WRITE_LITERAL,

I'll open a PR for that soon-ish, just figuring out the nicest way of carrying over the AST parts in a way that's easily shared with other modules

[m-ou-se]

Nice!

[Alexendoo]

Opened ☝️

[m-ou-se]

Is there anything I can do to move this forward? I think most (all) of the remaining lints are blocked on #10275?