bjoernager/rust
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recover import instead of use in item

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This commit is contained in:
Michael Goulet 2022-06-07 00:13:50 -07:00
parent 9f7e997c8b
commit b7ed860108
4 changed files with 93 additions and 20 deletions
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69
compiler/rustc_parse/src/parser/item.rs
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@ -204,25 +204,7 @@ impl<'a> Parser<'a> {
let mut def = || mem::replace(def, Defaultness::Final);
let info = if self.eat_keyword(kw::Use) {
// USE ITEM
let tree = self.parse_use_tree()?;
// If wildcard or glob-like brace syntax doesn't have `;`,
// the user may not know `*` or `{}` should be the last.
if let Err(mut e) = self.expect_semi() {
match tree.kind {
UseTreeKind::Glob => {
e.note("the wildcard token must be last on the path");
}
UseTreeKind::Nested(..) => {
e.note("glob-like brace syntax must be last on the path");
}
_ => (),
}
return Err(e);
}
(Ident::empty(), ItemKind::Use(tree))
self.parse_use_item()?
} else if self.check_fn_front_matter(def_final) {
// FUNCTION ITEM
let (ident, sig, generics, body) = self.parse_fn(attrs, fn_parse_mode, lo, vis)?;
@ -288,7 +270,12 @@ impl<'a> Parser<'a> {
} else if let IsMacroRulesItem::Yes { has_bang } = self.is_macro_rules_item() {
// MACRO_RULES ITEM
self.parse_item_macro_rules(vis, has_bang)?
} else if vis.kind.is_pub() && self.isnt_macro_invocation() {
} else if self.isnt_macro_invocation()
&& (self.token.is_ident_named(Symbol::intern("import"))
|| self.token.is_ident_named(Symbol::intern("using")))
{
return self.recover_import_as_use();
} else if self.isnt_macro_invocation() && vis.kind.is_pub() {
self.recover_missing_kw_before_item()?;
return Ok(None);
} else if macros_allowed && self.check_path() {
@ -300,6 +287,48 @@ impl<'a> Parser<'a> {
Ok(Some(info))
}
fn recover_import_as_use(&mut self) -> PResult<'a, Option<(Ident, ItemKind)>> {
let span = self.token.span;
let token_name = super::token_descr(&self.token);
let snapshot = self.create_snapshot_for_diagnostic();
self.bump();
match self.parse_use_item() {
Ok(u) => {
self.struct_span_err(span, format!("expected item, found {token_name}"))
.span_suggestion_short(
span,
"items are imported using the `use` keyword",
"use".to_owned(),
Applicability::MachineApplicable,
)
.emit();
Ok(Some(u))
}
Err(e) => {
e.cancel();
self.restore_snapshot(snapshot);
Ok(None)
}
}
}
fn parse_use_item(&mut self) -> PResult<'a, (Ident, ItemKind)> {
let tree = self.parse_use_tree()?;
if let Err(mut e) = self.expect_semi() {
match tree.kind {
UseTreeKind::Glob => {
e.note("the wildcard token must be last on the path");
}
UseTreeKind::Nested(..) => {
e.note("glob-like brace syntax must be last on the path");
}
_ => (),
}
return Err(e);
}
Ok((Ident::empty(), ItemKind::Use(tree)))
}
/// When parsing a statement, would the start of a path be an item?
pub(super) fn is_path_start_item(&mut self) -> bool {
self.is_kw_followed_by_ident(kw::Union) // no: `union::b`, yes: `union U { .. }`