bjoernager/rust
bjoernager/rust
1
Fork 0
Code Activity

remove unnecessary string searchings

Browse source 
remove unnecessary string searchings for checking if function arguments have `&` and `&mut`
This commit is contained in:
Takayuki Maeda 2022-08-20 15:54:39 +09:00
parent 75b7e52e92
commit 973510749d
4 changed files with 35 additions and 26 deletions
Download patch file Download diff file Expand all files Collapse all files

31
compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs
View file

@ -671,7 +671,7 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> {
trait_pred: ty::PolyTraitPredicate<'tcx>,
) -> bool {
// It only make sense when suggesting dereferences for arguments
let ObligationCauseCode::FunctionArgumentObligation { .. } = obligation.cause.code() else {
let ObligationCauseCode::FunctionArgumentObligation { arg_hir_id, .. } = obligation.cause.code() else {
return false;
};
let param_env = obligation.param_env;
@ -702,19 +702,22 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> {
Some(steps).filter(|_| self.predicate_may_hold(&obligation))
}) {
if steps > 0 {
if let Ok(src) = self.tcx.sess.source_map().span_to_snippet(span) {
// Don't care about `&mut` because `DerefMut` is used less
// often and user will not expect autoderef happens.
if src.starts_with('&') && !src.starts_with("&mut ") {
let derefs = "*".repeat(steps);
err.span_suggestion(
span,
"consider dereferencing here",
format!("&{}{}", derefs, &src[1..]),
Applicability::MachineApplicable,
);
return true;
}
// Don't care about `&mut` because `DerefMut` is used less
// often and user will not expect autoderef happens.
if let Some(hir::Node::Expr(hir::Expr {
kind:
hir::ExprKind::AddrOf(hir::BorrowKind::Ref, hir::Mutability::Not, expr),
..
})) = self.tcx.hir().find(*arg_hir_id)
{
let derefs = "*".repeat(steps);
err.span_suggestion_verbose(
expr.span.shrink_to_lo(),
"consider dereferencing here",
derefs,
Applicability::MachineApplicable,
);
return true;
}
}
} else if real_trait_pred != trait_pred {