From d9f2fdfaed8d18ede6d113426279c86d84d92445 Mon Sep 17 00:00:00 2001
From: Nicholas Nethercote <n.nethercote@gmail.com>
Date: Mon, 31 Jul 2023 15:47:19 +1000
Subject: `parse_all_token_trees` cannot fail.

---
 src/librustdoc/clean/render_macro_matchers.rs | 8 +-------
 1 file changed, 1 insertion(+), 7 deletions(-)

(limited to 'src/librustdoc')

diff --git a/src/librustdoc/clean/render_macro_matchers.rs b/src/librustdoc/clean/render_macro_matchers.rs
index ef38ca3c16c..b6120e814df 100644
--- a/src/librustdoc/clean/render_macro_matchers.rs
+++ b/src/librustdoc/clean/render_macro_matchers.rs
@@ -76,13 +76,7 @@ fn snippet_equal_to_token(tcx: TyCtxt<'_>, matcher: &TokenTree) -> Option<String
         };
 
     // Reparse a single token tree.
-    let mut reparsed_trees = match parser.parse_all_token_trees() {
-        Ok(reparsed_trees) => reparsed_trees,
-        Err(diagnostic) => {
-            diagnostic.cancel();
-            return None;
-        }
-    };
+    let mut reparsed_trees = parser.parse_all_token_trees();
     if reparsed_trees.len() != 1 {
         return None;
     }
-- 
cgit 1.4.1-3-g733a5


From db7b07aa028b65b4d85610e81fecb0d2382b8c76 Mon Sep 17 00:00:00 2001
From: Nicholas Nethercote <n.nethercote@gmail.com>
Date: Mon, 31 Jul 2023 15:51:08 +1000
Subject: Inline and remove `parse_all_token_trees`.

It has a single call site.
---
 compiler/rustc_parse/src/parser/mod.rs        | 11 +----------
 src/librustdoc/clean/render_macro_matchers.rs |  5 ++++-
 2 files changed, 5 insertions(+), 11 deletions(-)

(limited to 'src/librustdoc')

diff --git a/compiler/rustc_parse/src/parser/mod.rs b/compiler/rustc_parse/src/parser/mod.rs
index b452eb6a401..4b23f5a6de1 100644
--- a/compiler/rustc_parse/src/parser/mod.rs
+++ b/compiler/rustc_parse/src/parser/mod.rs
@@ -1251,7 +1251,7 @@ impl<'a> Parser<'a> {
     }
 
     /// Parses a single token tree from the input.
-    pub(crate) fn parse_token_tree(&mut self) -> TokenTree {
+    pub fn parse_token_tree(&mut self) -> TokenTree {
         match self.token.kind {
             token::OpenDelim(..) => {
                 // Grab the tokens within the delimiters.
@@ -1287,15 +1287,6 @@ impl<'a> Parser<'a> {
         }
     }
 
-    /// Parses a stream of tokens into a list of `TokenTree`s, up to EOF.
-    pub fn parse_all_token_trees(&mut self) -> Vec<TokenTree> {
-        let mut tts = Vec::new();
-        while self.token != token::Eof {
-            tts.push(self.parse_token_tree());
-        }
-        tts
-    }
-
     pub fn parse_tokens(&mut self) -> TokenStream {
         let mut result = Vec::new();
         loop {
diff --git a/src/librustdoc/clean/render_macro_matchers.rs b/src/librustdoc/clean/render_macro_matchers.rs
index b6120e814df..b3dc0f63e45 100644
--- a/src/librustdoc/clean/render_macro_matchers.rs
+++ b/src/librustdoc/clean/render_macro_matchers.rs
@@ -76,7 +76,10 @@ fn snippet_equal_to_token(tcx: TyCtxt<'_>, matcher: &TokenTree) -> Option<String
         };
 
     // Reparse a single token tree.
-    let mut reparsed_trees = parser.parse_all_token_trees();
+    let mut reparsed_trees = Vec::new();
+    while parser.token != token::Eof {
+        reparsed_trees.push(parser.parse_token_tree());
+    }
     if reparsed_trees.len() != 1 {
         return None;
     }
-- 
cgit 1.4.1-3-g733a5


From 203cba76e07c87c4e665b2e78ca0358b5a72e86a Mon Sep 17 00:00:00 2001
From: Nicholas Nethercote <n.nethercote@gmail.com>
Date: Mon, 31 Jul 2023 15:53:46 +1000
Subject: Only call `parse_token_tree` once.

This code currently uses a `while` loop and gathers token trees into a
vector, but it only succeeds in the case where there is a single token
tree. We can instead just call `parse_token_tree` once and then look for
`Eof` to detect the success case.
---
 src/librustdoc/clean/render_macro_matchers.rs | 9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

(limited to 'src/librustdoc')

diff --git a/src/librustdoc/clean/render_macro_matchers.rs b/src/librustdoc/clean/render_macro_matchers.rs
index b3dc0f63e45..66d10f2368b 100644
--- a/src/librustdoc/clean/render_macro_matchers.rs
+++ b/src/librustdoc/clean/render_macro_matchers.rs
@@ -76,14 +76,13 @@ fn snippet_equal_to_token(tcx: TyCtxt<'_>, matcher: &TokenTree) -> Option<String
         };
 
     // Reparse a single token tree.
-    let mut reparsed_trees = Vec::new();
-    while parser.token != token::Eof {
-        reparsed_trees.push(parser.parse_token_tree());
+    if parser.token == token::Eof {
+        return None;
     }
-    if reparsed_trees.len() != 1 {
+    let reparsed_tree = parser.parse_token_tree();
+    if parser.token != token::Eof {
         return None;
     }
-    let reparsed_tree = reparsed_trees.pop().unwrap();
 
     // Compare against the original tree.
     if reparsed_tree.eq_unspanned(matcher) { Some(snippet) } else { None }
-- 
cgit 1.4.1-3-g733a5