bjoernager/rust
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Refine when invalid prefix case error arises

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Fix cases where the "invalid base prefix for number literal" error arises with
suffixes that look erroneously capitalized but which are in fact invalid.
This commit is contained in:
Cassaundra Smith 2022-12-01 19:17:03 -08:00
parent 2585bcea0b
commit 52a9280fb2
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GPG key ID: E8087B0F3D674D9B
3 changed files with 107 additions and 10 deletions
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33
compiler/rustc_session/src/errors.rs
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@ -291,20 +291,33 @@ pub fn report_lit_error(sess: &ParseSess, err: LitError, lit: token::Lit, span:
s.len() > 1 && s.starts_with(first_chars) && s[1..].chars().all(|c| c.is_ascii_digit())
}
// Try to lowercase the prefix if it's a valid base prefix.
fn fix_base_capitalisation(s: &str) -> Option<String> {
if let Some(stripped) = s.strip_prefix('B') {
Some(format!("0b{stripped}"))
} else if let Some(stripped) = s.strip_prefix('O') {
Some(format!("0o{stripped}"))
} else if let Some(stripped) = s.strip_prefix('X') {
Some(format!("0x{stripped}"))
// Try to lowercase the prefix if the prefix and suffix are valid.
fn fix_base_capitalisation(prefix: &str, suffix: &str) -> Option<String> {
let mut chars = suffix.chars();
let base_char = chars.next().unwrap();
let base = match base_char {
'B' => 2,
'O' => 8,
'X' => 16,
_ => return None,
};
// check that the suffix contains only base-appropriate characters
let valid = prefix == "0"
&& chars
.filter(|c| *c != '_')
.take_while(|c| *c != 'i' && *c != 'u')
.all(|c| c.to_digit(base).is_some());
if valid {
Some(format!("0{}{}", base_char.to_ascii_lowercase(), &suffix[1..]))
} else {
None
}
}
let token::Lit { kind, suffix, .. } = lit;
let token::Lit { kind, symbol, suffix, .. } = lit;
match err {
// `LexerError` is an error, but it was already reported
// by lexer, so here we don't report it the second time.
@ -324,7 +337,7 @@ pub fn report_lit_error(sess: &ParseSess, err: LitError, lit: token::Lit, span:
if looks_like_width_suffix(&['i', 'u'], &suf) {
// If it looks like a width, try to be helpful.
sess.emit_err(InvalidIntLiteralWidth { span, width: suf[1..].into() });
} else if let Some(fixed) = fix_base_capitalisation(suf) {
} else if let Some(fixed) = fix_base_capitalisation(symbol.as_str(), suf) {
sess.emit_err(InvalidNumLiteralBasePrefix { span, fixed });
} else {
sess.emit_err(InvalidNumLiteralSuffix { span, suffix: suf.to_string() });