bjoernager/rust
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Do not emit type errors on recovered blocks

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When a parse error occurs on a block, the parser will recover and create
a block with the statements collected until that point. Now a flag
stating that a recovery has been performed in this block is propagated
so that the type checker knows that the type of the block (which will be
identified as `()`) shouldn't be checked against the expectation to
reduce the amount of irrelevant diagnostic errors shown to the user.
This commit is contained in:
Esteban Küber 2017-12-13 23:05:49 -08:00
parent b7b52cc8bf
commit aaf3e318fc
25 changed files with 112 additions and 41 deletions
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7
src/libsyntax/parse/parser.rs
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@ -4371,13 +4371,15 @@ impl<'a> Parser<'a> {
/// Precondition: already parsed the '{'.
fn parse_block_tail(&mut self, lo: Span, s: BlockCheckMode) -> PResult<'a, P<Block>> {
let mut stmts = vec![];
let mut recovered = false;
while !self.eat(&token::CloseDelim(token::Brace)) {
let stmt = match self.parse_full_stmt(false) {
Err(mut err) => {
err.emit();
self.recover_stmt_(SemiColonMode::Ignore, BlockMode::Break);
self.recover_stmt_(SemiColonMode::Ignore, BlockMode::Ignore);
self.eat(&token::CloseDelim(token::Brace));
recovered = true;
break;
}
Ok(stmt) => stmt,
@ -4396,12 +4398,13 @@ impl<'a> Parser<'a> {
id: ast::DUMMY_NODE_ID,
rules: s,
span: lo.to(self.prev_span),
recovered,
}))
}
/// Parse a statement, including the trailing semicolon.
pub fn parse_full_stmt(&mut self, macro_legacy_warnings: bool) -> PResult<'a, Option<Stmt>> {
let mut stmt = match self.parse_stmt_(macro_legacy_warnings) {
let mut stmt = match self.parse_stmt_without_recovery(macro_legacy_warnings)? {
Some(stmt) => stmt,
None => return Ok(None),
};