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lexer: Tiny improvement to shebang detection

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Lexer now discerns between regular comments and doc comments, so use that.
The change only affects the choice of reported errors.
This commit is contained in:
Vadim Petrochenkov 2020-09-02 00:22:47 +03:00
parent eb9e7c357e
commit b1491eacfc
3 changed files with 14 additions and 13 deletions
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14
compiler/rustc_lexer/src/lib.rs
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@ -191,12 +191,16 @@ pub fn strip_shebang(input: &str) -> Option<usize> {
// For simplicity we consider any line starting with `#!` a shebang,
// regardless of restrictions put on shebangs by specific platforms.
if let Some(input_tail) = input.strip_prefix("#!") {
// Ok, this is a shebang but if the next non-whitespace token is `[` or maybe
// a doc comment (due to `TokenKind::(Line,Block)Comment` ambiguity at lexer level),
// Ok, this is a shebang but if the next non-whitespace token is `[`,
// then it may be valid Rust code, so consider it Rust code.
let next_non_whitespace_token = tokenize(input_tail).map(|tok| tok.kind).find(|tok|
!matches!(tok, TokenKind::Whitespace | TokenKind::LineComment { .. } | TokenKind::BlockComment { .. })
);
let next_non_whitespace_token = tokenize(input_tail).map(|tok| tok.kind).find(|tok| {
!matches!(
tok,
TokenKind::Whitespace
| TokenKind::LineComment { doc_style: None }
| TokenKind::BlockComment { doc_style: None, .. }
)
});
if next_non_whitespace_token != Some(TokenKind::OpenBracket) {
// No other choice than to consider this a shebang.
return Some(2 + input_tail.lines().next().unwrap_or_default().len());