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When recovering from a : in a pattern, use adequate AST pattern

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This commit is contained in:
Esteban Küber 2021-07-15 08:36:19 -07:00 • committed by Esteban Kuber
parent 862962b90e
commit d6e34ad108
3 changed files with 152 additions and 46 deletions
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103
compiler/rustc_parse/src/parser/pat.rs
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@ -3,13 +3,17 @@ use crate::{maybe_recover_from_interpolated_ty_qpath, maybe_whole};
use rustc_ast::mut_visit::{noop_visit_pat, MutVisitor};
use rustc_ast::ptr::P;
use rustc_ast::token;
use rustc_ast::{self as ast, AttrVec, Attribute, MacCall, Pat, PatField, PatKind, RangeEnd};
use rustc_ast::{BindingMode, Expr, ExprKind, Mutability, Path, QSelf, RangeSyntax};
use rustc_ast::{
self as ast, AttrVec, Attribute, BindingMode, Expr, ExprKind, MacCall, Mutability, Pat,
PatField, PatKind, Path, PathSegment, QSelf, RangeEnd, RangeSyntax,
};
use rustc_ast_pretty::pprust;
use rustc_errors::{struct_span_err, Applicability, DiagnosticBuilder, PResult};
use rustc_span::source_map::{respan, Span, Spanned};
use rustc_span::symbol::{kw, sym, Ident};
use std::mem::take;
type Expected = Option<&'static str>;
/// `Expected` for function and lambda parameter patterns.
@ -101,11 +105,8 @@ impl<'a> Parser<'a> {
let mut first_pat = first_pat;
if let (RecoverColon::Yes, token::Colon) = (ra, &self.token.kind) {
if matches!(
first_pat.kind,
PatKind::Ident(BindingMode::ByValue(Mutability::Not), _, None)
| PatKind::Path(..)
) && self.look_ahead(1, |token| token.is_ident() && !token.is_reserved_ident())
if matches!(first_pat.kind, PatKind::Ident(_, _, None) | PatKind::Path(..))
&& self.look_ahead(1, |token| token.is_ident() && !token.is_reserved_ident())
{
// The pattern looks like it might be a path with a `::` -> `:` typo:
// `match foo { bar:baz => {} }`
@ -126,17 +127,87 @@ impl<'a> Parser<'a> {
err.cancel();
*self = snapshot;
}
Ok(pat) => {
Ok(mut pat) => {
// We've parsed the rest of the pattern.
err.span_suggestion(
span,
"maybe write a path separator here",
"::".to_string(),
Applicability::MachineApplicable,
);
let new_span = first_pat.span.to(pat.span);
let mut show_sugg = false;
match &mut pat.kind {
PatKind::Struct(qself @ None, path, ..)
| PatKind::TupleStruct(qself @ None, path, _)
| PatKind::Path(qself @ None, path) => {
match &first_pat.kind {
PatKind::Ident(_, ident, _) => {
path.segments.insert(
0,
PathSegment::from_ident(ident.clone()),
);
path.span = new_span;
show_sugg = true;
first_pat = pat;
}
PatKind::Path(old_qself, old_path) => {
path.segments = old_path
.segments
.iter()
.cloned()
.chain(take(&mut path.segments))
.collect();
path.span = new_span;
*qself = old_qself.clone();
first_pat = pat;
show_sugg = true;
}
_ => {}
}
}
PatKind::Ident(
BindingMode::ByValue(Mutability::Not),
ident,
None,
) => match &first_pat.kind {
PatKind::Ident(_, old_ident, _) => {
let path = PatKind::Path(
None,
Path {
span: new_span,
segments: vec![
PathSegment::from_ident(
old_ident.clone(),
),
PathSegment::from_ident(ident.clone()),
],
tokens: None,
},
);
first_pat = self.mk_pat(new_span, path);
show_sugg = true;
}
PatKind::Path(old_qself, old_path) => {
let mut segments = old_path.segments.clone();
segments
.push(PathSegment::from_ident(ident.clone()));
let path = PatKind::Path(
old_qself.clone(),
Path { span: new_span, segments, tokens: None },
);
first_pat = self.mk_pat(new_span, path);
show_sugg = true;
}
_ => {}
},
_ => {}
}
if show_sugg {
err.span_suggestion(
span,
"maybe write a path separator here",
"::".to_string(),
Applicability::MachineApplicable,
);
} else {
first_pat = self.mk_pat(new_span, PatKind::Wild);
}
err.emit();
first_pat =
self.mk_pat(first_pat.span.to(pat.span), PatKind::Wild);
}
}
}