bjoernager/rust
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Recover from parse errors in struct literal fields

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Attempt to recover from parse errors while parsing a struct's literal fields
by skipping tokens until a comma or the closing brace is found. This allows
errors in other fields to be reported.
This commit is contained in:
Esteban Küber 2019-01-20 00:37:06 -08:00
parent 0c0c585281
commit b1f169fe7a
7 changed files with 132 additions and 15 deletions
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47
src/libsyntax/parse/parser.rs
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@ -100,6 +100,7 @@ pub enum PathStyle {
enum SemiColonMode {
Break,
Ignore,
Comma,
}
#[derive(Clone, Copy, PartialEq, Debug)]
@ -2656,18 +2657,37 @@ impl<'a> Parser<'a> {
break;
}
let mut recovery_field = None;
if let token::Ident(ident, _) = self.token {
if !self.token.is_reserved_ident() {
let mut ident = ident.clone();
ident.span = self.span;
recovery_field = Some(ast::Field {
ident,
span: self.span,
expr: self.mk_expr(self.span, ExprKind::Err, ThinVec::new()),
is_shorthand: true,
attrs: ThinVec::new(),
});
}
}
match self.parse_field() {
Ok(f) => fields.push(f),
Err(mut e) => {
e.span_label(struct_sp, "while parsing this struct");
e.emit();
if let Some(f) = recovery_field {
fields.push(f);
}
// If the next token is a comma, then try to parse
// what comes next as additional fields, rather than
// bailing out until next `}`.
if self.token != token::Comma {
self.recover_stmt();
break;
self.recover_stmt_(SemiColonMode::Comma, BlockMode::Ignore);
if self.token != token::Comma {
break;
}
}
}
}
@ -2676,9 +2696,10 @@ impl<'a> Parser<'a> {
&[token::CloseDelim(token::Brace)]) {
Ok(()) => {}
Err(mut e) => {
e.span_label(struct_sp, "while parsing this struct");
e.emit();
self.recover_stmt();
break;
self.recover_stmt_(SemiColonMode::Comma, BlockMode::Ignore);
self.eat(&token::Comma);
}
}
}
@ -4538,13 +4559,13 @@ impl<'a> Parser<'a> {
token::CloseDelim(token::DelimToken::Brace) => {
if brace_depth == 0 {
debug!("recover_stmt_ return - close delim {:?}", self.token);
return;
break;
}
brace_depth -= 1;
self.bump();
if in_block && bracket_depth == 0 && brace_depth == 0 {
debug!("recover_stmt_ return - block end {:?}", self.token);
return;
break;
}
}
token::CloseDelim(token::DelimToken::Bracket) => {
@ -4556,7 +4577,7 @@ impl<'a> Parser<'a> {
}
token::Eof => {
debug!("recover_stmt_ return - Eof");
return;
break;
}
token::Semi => {
self.bump();
@ -4564,7 +4585,17 @@ impl<'a> Parser<'a> {
brace_depth == 0 &&
bracket_depth == 0 {
debug!("recover_stmt_ return - Semi");
return;
break;
}
}
token::Comma => {
if break_on_semi == SemiColonMode::Comma &&
brace_depth == 0 &&
bracket_depth == 0 {
debug!("recover_stmt_ return - Semi");
break;
} else {
self.bump();
}
}
_ => {