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Remove an impossible code path.

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Doc comments cannot appear in a matcher.
This commit is contained in:
Nicholas Nethercote 2022-03-19 08:07:04 +11:00
parent 39810a85da
commit 10644e0789
1 changed files with 6 additions and 5 deletions
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11
compiler/rustc_expand/src/mbe/macro_parser.rs
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@ -593,11 +593,9 @@ impl TtParser {
}
}
seq @ (TokenTree::Delimited(..)
| TokenTree::Token(Token { kind: DocComment(..), .. })) => {
// To descend into a delimited submatcher or a doc comment, we push the
// current matcher onto a stack and push a new item containing the
// submatcher onto `cur_items`.
seq @ TokenTree::Delimited(..) => {
// To descend into a delimited submatcher, we push the current matcher onto
// a stack and push a new item containing the submatcher onto `cur_items`.
//
// At the beginning of the loop, if we reach the end of the delimited
// submatcher, we pop the stack to backtrack out of the descent.
@ -609,6 +607,9 @@ impl TtParser {
}
TokenTree::Token(t) => {
// Doc comments cannot appear in a matcher.
debug_assert!(!matches!(t, Token { kind: DocComment(..), .. }));
// If the token matches, we can just advance the parser. Otherwise, this
// match hash failed, there is nothing to do, and hopefully another item in
// `cur_items` will match.