bjoernager/rust
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Improve spans for indexing expressions

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Indexing is similar to method calls in having an arbitrary
left-hand-side and then something on the right, which is the main part
of the expression. Method calls already have a span for that right part,
but indexing does not. This means that long method chains that use
indexing have really bad spans, especially when the indexing panics and
that span in coverted into a panic location.

This does the same thing as method calls for the AST and HIR, storing an
extra span which is then put into the `fn_span` field in THIR.
This commit is contained in:
Nilstrieb 2023-08-03 21:43:17 +02:00
parent fcf3006e01
commit 5706be1854
82 changed files with 192 additions and 149 deletions
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11
compiler/rustc_parse/src/parser/expr.rs
View file

@ -857,7 +857,7 @@ impl<'a> Parser<'a> {
let msg = format!(
"cast cannot be followed by {}",
match with_postfix.kind {
ExprKind::Index(_, _) => "indexing",
ExprKind::Index(..) => "indexing",
ExprKind::Try(_) => "`?`",
ExprKind::Field(_, _) => "a field access",
ExprKind::MethodCall(_) => "a method call",
@ -1304,7 +1304,10 @@ impl<'a> Parser<'a> {
let index = self.parse_expr()?;
self.suggest_missing_semicolon_before_array(prev_span, open_delim_span)?;
self.expect(&token::CloseDelim(Delimiter::Bracket))?;
Ok(self.mk_expr(lo.to(self.prev_token.span), self.mk_index(base, index)))
Ok(self.mk_expr(
lo.to(self.prev_token.span),
self.mk_index(base, index, open_delim_span.to(self.prev_token.span)),
))
}
/// Assuming we have just parsed `.`, continue parsing into an expression.
@ -3366,8 +3369,8 @@ impl<'a> Parser<'a> {
ExprKind::Binary(binop, lhs, rhs)
}
fn mk_index(&self, expr: P<Expr>, idx: P<Expr>) -> ExprKind {
ExprKind::Index(expr, idx)
fn mk_index(&self, expr: P<Expr>, idx: P<Expr>, brackets_span: Span) -> ExprKind {
ExprKind::Index(expr, idx, brackets_span)
}
fn mk_call(&self, f: P<Expr>, args: ThinVec<P<Expr>>) -> ExprKind {