From e8d02fe1cb20a21e0bee2f80f1e16945eb3b9437 Mon Sep 17 00:00:00 2001
From: Nicholas Nethercote <n.nethercote@gmail.com>
Date: Fri, 31 May 2024 15:43:18 +1000
Subject: [PATCH] Make top-level `rustc_parse` functions fallible.

Currently we have an awkward mix of fallible and infallible functions:
```
       new_parser_from_source_str
 maybe_new_parser_from_source_str
       new_parser_from_file
(maybe_new_parser_from_file)        // missing
      (new_parser_from_source_file) // missing
 maybe_new_parser_from_source_file
       source_str_to_stream
 maybe_source_file_to_stream
```
We could add the two missing functions, but instead this commit removes
of all the infallible ones and renames the fallible ones leaving us with
these which are all fallible:
```
new_parser_from_source_str
new_parser_from_file
new_parser_from_source_file
source_str_to_stream
source_file_to_stream
```
This requires making `unwrap_or_emit_fatal` public so callers of
formerly infallible functions can still work.

This does make some of the call sites slightly more verbose, but I think
it's worth it for the simpler API. Also, there are two `catch_unwind`
calls and one `catch_fatal_errors` call in this diff that become
removable thanks this change. (I will do that in a follow-up PR.)
---
 clippy_lints/src/doc/needless_doctest_main.rs | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/clippy_lints/src/doc/needless_doctest_main.rs b/clippy_lints/src/doc/needless_doctest_main.rs
index 651f2ebaee6f..c3e3c0431e6b 100644
--- a/clippy_lints/src/doc/needless_doctest_main.rs
+++ b/clippy_lints/src/doc/needless_doctest_main.rs
@@ -8,7 +8,7 @@ use rustc_data_structures::sync::Lrc;
 use rustc_errors::emitter::HumanEmitter;
 use rustc_errors::{Diag, DiagCtxt};
 use rustc_lint::LateContext;
-use rustc_parse::maybe_new_parser_from_source_str;
+use rustc_parse::new_parser_from_source_str;
 use rustc_parse::parser::ForceCollect;
 use rustc_session::parse::ParseSess;
 use rustc_span::edition::Edition;
@@ -50,7 +50,7 @@ pub fn check(
                 let sm = Lrc::new(SourceMap::new(FilePathMapping::empty()));
                 let psess = ParseSess::with_dcx(dcx, sm);
 
-                let mut parser = match maybe_new_parser_from_source_str(&psess, filename, code) {
+                let mut parser = match new_parser_from_source_str(&psess, filename, code) {
                     Ok(p) => p,
                     Err(errs) => {
                         errs.into_iter().for_each(Diag::cancel);