FormatArgsExpn: Find comma spans and ignore weird proc macro spans

[Alexendoo]

Fixes the following cases:

A missing , 1 from the expect_fun_call suggestion:

Some(()).expect(&format!("{x} {}", 1));

warning: use of `expect` followed by a function call
 --> t.rs:7:14
  |
7 |     Some(()).expect(&format!("{x} {}", 1));
  |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try this: `unwrap_or_else(|| panic!("{x} {}"))`

The suggestion removing from the comma in the comment rather than the one after the format string:

println!(
    "{}",
    // a comment, with a comma in it
    x
);

warning: variables can be used directly in the `format!` string
  --> t.rs:9:5
   |
9  | /     println!(
10 | |         "{}",
11 | |         // a comment, with a comma in it
12 | |         x
13 | |     );
   | |_____^
   |
help: change this to
   |
10 ~         "{x}",
11 ~         // a comment
   |

It also no longer accepts expansions where a format string or argument has a "weird" proc macro span, that is one where the literal/expression it outputs has the span of one of its inputs. Kind of like a format_args specific clippy_utils::is_from_proc_macro, e.g. format!(indoc! {" ... "})

changelog: [expect_fun_call]: Fix suggestion for format! using captured variables
changelog: [print_literal], [write_literal], [uninlined_format_args]: Fix suggestion when following a comment including a comma

[rust-highfive]

r? @Manishearth

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[bors]

☔ The latest upstream changes (presumably #9547) made this pull request unmergeable. Please resolve the merge conflicts.

[nyurik]

Overall looks good to me! One thing you may want to reuse - I trimmed down the indoc! macro in the unit tests for #9548 -- the simple_indoc -- would it make sense to merge that unit test into your code here?

[Alexendoo]

with_span! covers the case where a proc macro sets the output span to one of its inputs

[Manishearth]

nit: fmt_args_comma_spans?

[Manishearth]

or perhaps as a static fn on the format args expansion helper type

[Alexendoo]

👍

Changed

[Manishearth]

r=me, one nit

[Manishearth]

@bors r+

(Thanks for the additional review help, @nyurik!)

[bors]

📌 Commit 9226066 has been approved by Manishearth

It is now in the queue for this repository.

[bors]

⌛ Testing commit 9226066 with merge 887ba0c...

[bors]

☀️ Test successful - checks-action_dev_test, checks-action_remark_test, checks-action_test
Approved by: Manishearth
Pushing 887ba0c to master...

[bors]

☀️ Test successful - checks-action_dev_test, checks-action_remark_test, checks-action_test
Approved by: Manishearth
Pushing 887ba0c to master...

[nyurik]

we may want to clarify this comment -- the above format!(...) doesn't look like valid code.

[Alexendoo]

Ah whoops, the {y} should be {}. I also forgot to remove the FIXME if you fancy doing a cleanup PR, otherwise I'll get around to it