bjoernager/rust
bjoernager/rust
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Address review comments

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- Add doc comment to new type
- Restore "only supported directly in conditions of `if` and `while` expressions" note
- Rename variant with clearer name
This commit is contained in:
Matthew Jasper 2023-09-13 15:00:31 +00:00
parent b011a0a13b
commit e324a59eb6
15 changed files with 362 additions and 4 deletions
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1
compiler/rustc_parse/src/errors.rs
View file

@ -392,6 +392,7 @@ pub(crate) struct IfExpressionMissingCondition {
#[derive(Diagnostic)]
#[diag(parse_expected_expression_found_let)]
#[note]
pub(crate) struct ExpectedExpressionFoundLet {
#[primary_span]
pub span: Span,

17
compiler/rustc_parse/src/parser/expr.rs
View file

@ -2461,7 +2461,7 @@ impl<'a> Parser<'a> {
let is_recovered = if !restrictions.contains(Restrictions::ALLOW_LET) {
Some(self.sess.emit_err(errors::ExpectedExpressionFoundLet {
span: self.token.span,
reason: ForbiddenLetReason::GenericForbidden,
reason: ForbiddenLetReason::OtherForbidden,
}))
} else {
None
@ -3427,7 +3427,7 @@ impl<'a> Parser<'a> {
#[derive(Clone, Copy, Subdiagnostic)]
pub(crate) enum ForbiddenLetReason {
/// `let` is not valid and the source environment is not important
GenericForbidden,
OtherForbidden,
/// A let chain with the `||` operator
#[note(parse_not_supported_or)]
NotSupportedOr(#[primary_span] Span),
@ -3439,6 +3439,15 @@ pub(crate) enum ForbiddenLetReason {
NotSupportedParentheses(#[primary_span] Span),
}
/// Visitor to check for invalid/unstable use of `ExprKind::Let` that can't
/// easily be caught in parsing. For example:
///
/// ```rust,ignore (example)
/// // Only know that the let isn't allowed once the `||` token is reached
/// if let Some(x) = y || true {}
/// // Only know that the let isn't allowed once the second `=` token is reached.
/// if let Some(x) = y && z = 1 {}
/// ```
struct CondChecker<'a> {
parser: &'a Parser<'a>,
forbid_let_reason: Option<ForbiddenLetReason>,
@ -3495,14 +3504,14 @@ impl MutVisitor for CondChecker<'_> {
| ExprKind::Tup(_)
| ExprKind::Paren(_) => {
let forbid_let_reason = self.forbid_let_reason;
self.forbid_let_reason = Some(GenericForbidden);
self.forbid_let_reason = Some(OtherForbidden);
noop_visit_expr(e, self);
self.forbid_let_reason = forbid_let_reason;
}
ExprKind::Cast(ref mut op, _)
| ExprKind::Type(ref mut op, _) => {
let forbid_let_reason = self.forbid_let_reason;
self.forbid_let_reason = Some(GenericForbidden);
self.forbid_let_reason = Some(OtherForbidden);
self.visit_expr(op);
self.forbid_let_reason = forbid_let_reason;
}