bjoernager/rust
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Move PatKind::Lit checking from ast_validation to ast lowering

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Fixes #92074

This allows us to insert an `ExprKind::Err` when an invalid expression
is used in a literal pattern, preventing later stages of compilation
from seeing an unexpected literal pattern.
This commit is contained in:
Aaron Hill 2021-12-18 12:23:49 -05:00
parent 4f49627c6f
commit 137c374c41
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GPG key ID: B4087E510E98B164
5 changed files with 111 additions and 56 deletions
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47
compiler/rustc_ast_passes/src/ast_validation.rs
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@ -302,34 +302,6 @@ impl<'a> AstValidator<'a> {
}
}
/// Matches `'-' lit | lit (cf. parser::Parser::parse_literal_maybe_minus)`,
/// or paths for ranges.
//
// FIXME: do we want to allow `expr -> pattern` conversion to create path expressions?
// That means making this work:
//
// ```rust,ignore (FIXME)
// struct S;
// macro_rules! m {
// ($a:expr) => {
// let $a = S;
// }
// }
// m!(S);
// ```
fn check_expr_within_pat(&self, expr: &Expr, allow_paths: bool) {
match expr.kind {
ExprKind::Lit(..) | ExprKind::ConstBlock(..) | ExprKind::Err => {}
ExprKind::Path(..) if allow_paths => {}
ExprKind::Unary(UnOp::Neg, ref inner) if matches!(inner.kind, ExprKind::Lit(_)) => {}
_ => self.err_handler().span_err(
expr.span,
"arbitrary expressions aren't allowed \
in patterns",
),
}
}
fn check_late_bound_lifetime_defs(&self, params: &[GenericParam]) {
// Check only lifetime parameters are present and that the lifetime
// parameters that are present have no bounds.
@ -1426,25 +1398,6 @@ impl<'a> Visitor<'a> for AstValidator<'a> {
visit::walk_param_bound(self, bound)
}
fn visit_pat(&mut self, pat: &'a Pat) {
match &pat.kind {
PatKind::Lit(expr) => {
self.check_expr_within_pat(expr, false);
}
PatKind::Range(start, end, _) => {
if let Some(expr) = start {
self.check_expr_within_pat(expr, true);
}
if let Some(expr) = end {
self.check_expr_within_pat(expr, true);
}
}
_ => {}
}
visit::walk_pat(self, pat)
}
fn visit_poly_trait_ref(&mut self, t: &'a PolyTraitRef, m: &'a TraitBoundModifier) {
self.check_late_bound_lifetime_defs(&t.bound_generic_params);
visit::walk_poly_trait_ref(self, t, m);