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remove unnecessary string searchings

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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
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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 {

10
src/test/ui/traits/suggest-deferences/issue-39029.stderr
View file

@ -2,10 +2,8 @@ error[E0277]: the trait bound `NoToSocketAddrs: ToSocketAddrs` is not satisfied
--> $DIR/issue-39029.rs:16:37
|
LL | let _errors = TcpListener::bind(&bad);
| ----------------- ^^^^
| | |
| | the trait `ToSocketAddrs` is not implemented for `NoToSocketAddrs`
| | help: consider dereferencing here: `&*bad`
| ----------------- ^^^^ the trait `ToSocketAddrs` is not implemented for `NoToSocketAddrs`
| |
| required by a bound introduced by this call
|
= note: required because of the requirements on the impl of `ToSocketAddrs` for `&NoToSocketAddrs`
@ -14,6 +12,10 @@ note: required by a bound in `TcpListener::bind`
|
LL | pub fn bind<A: ToSocketAddrs>(addr: A) -> io::Result<TcpListener> {
| ^^^^^^^^^^^^^ required by this bound in `TcpListener::bind`
help: consider dereferencing here
|
LL | let _errors = TcpListener::bind(&*bad);
| +
error: aborting due to previous error

10
src/test/ui/traits/suggest-deferences/issue-62530.stderr
View file

@ -2,10 +2,8 @@ error[E0277]: the trait bound `&String: SomeTrait` is not satisfied
--> $DIR/issue-62530.rs:13:26
|
LL | takes_type_parameter(&string); // Error
| -------------------- ^^^^^^^
| | |
| | the trait `SomeTrait` is not implemented for `&String`
| | help: consider dereferencing here: `&*string`
| -------------------- ^^^^^^^ the trait `SomeTrait` is not implemented for `&String`
| |
| required by a bound introduced by this call
|
note: required by a bound in `takes_type_parameter`
@ -13,6 +11,10 @@ note: required by a bound in `takes_type_parameter`
|
LL | fn takes_type_parameter<T>(_x: T) where T: SomeTrait {}
| ^^^^^^^^^ required by this bound in `takes_type_parameter`
help: consider dereferencing here
|
LL | takes_type_parameter(&*string); // Error
| +
error: aborting due to previous error

10
src/test/ui/traits/suggest-deferences/multiple-0.stderr
View file

@ -2,10 +2,8 @@ error[E0277]: the trait bound `&Baz: Happy` is not satisfied
--> $DIR/multiple-0.rs:34:9
|
LL | foo(&baz);
| --- ^^^^
| | |
| | the trait `Happy` is not implemented for `&Baz`
| | help: consider dereferencing here: `&***baz`
| --- ^^^^ the trait `Happy` is not implemented for `&Baz`
| |
| required by a bound introduced by this call
|
note: required by a bound in `foo`
@ -13,6 +11,10 @@ note: required by a bound in `foo`
|
LL | fn foo<T>(_: T) where T: Happy {}
| ^^^^^ required by this bound in `foo`
help: consider dereferencing here
|
LL | foo(&***baz);
| +++
error: aborting due to previous error