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Rollup merge of #112517 - fee1-dead-contrib:sus-op-no-borrow, r=compiler-errors

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`suspicious_double_ref_op`: don't lint on `.borrow()`

closes #112489
This commit is contained in:
Guillaume Gomez 2023-06-15 22:04:55 +02:00 • committed by GitHub
commit db7d8374c1
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4 changed files with 64 additions and 39 deletions
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12
compiler/rustc_lint/src/lints.rs
View file

@ -1231,11 +1231,15 @@ pub struct NoopMethodCallDiag<'a> {
}
#[derive(LintDiagnostic)]
#[diag(lint_suspicious_double_ref_op)]
pub struct SuspiciousDoubleRefDiag<'a> {
pub call: Symbol,
#[diag(lint_suspicious_double_ref_deref)]
pub struct SuspiciousDoubleRefDerefDiag<'a> {
pub ty: Ty<'a>,
}
#[derive(LintDiagnostic)]
#[diag(lint_suspicious_double_ref_clone)]
pub struct SuspiciousDoubleRefCloneDiag<'a> {
pub ty: Ty<'a>,
pub op: &'static str,
}
// pass_by_value.rs

62
compiler/rustc_lint/src/noop_method_call.rs
View file

@ -1,5 +1,7 @@
use crate::context::LintContext;
use crate::lints::{NoopMethodCallDiag, SuspiciousDoubleRefDiag};
use crate::lints::{
NoopMethodCallDiag, SuspiciousDoubleRefCloneDiag, SuspiciousDoubleRefDerefDiag,
};
use crate::LateContext;
use crate::LateLintPass;
use rustc_hir::def::DefKind;
@ -76,22 +78,22 @@ impl<'tcx> LateLintPass<'tcx> for NoopMethodCall {
// We only care about method calls corresponding to the `Clone`, `Deref` and `Borrow`
// traits and ignore any other method call.
let did = match cx.typeck_results().type_dependent_def(expr.hir_id) {
// Verify we are dealing with a method/associated function.
Some((DefKind::AssocFn, did)) => match cx.tcx.trait_of_item(did) {
// Check that we're dealing with a trait method for one of the traits we care about.
Some(trait_id)
if matches!(
cx.tcx.get_diagnostic_name(trait_id),
Some(sym::Borrow | sym::Clone | sym::Deref)
) =>
{
did
}
_ => return,
},
_ => return,
let Some((DefKind::AssocFn, did)) =
cx.typeck_results().type_dependent_def(expr.hir_id)
else {
return;
};
let Some(trait_id) = cx.tcx.trait_of_item(did) else { return };
if !matches!(
cx.tcx.get_diagnostic_name(trait_id),
Some(sym::Borrow | sym::Clone | sym::Deref)
) {
return;
};
let substs = cx
.tcx
.normalize_erasing_regions(cx.param_env, cx.typeck_results().node_substs(expr.hir_id));
@ -102,13 +104,6 @@ impl<'tcx> LateLintPass<'tcx> for NoopMethodCall {
// (Re)check that it implements the noop diagnostic.
let Some(name) = cx.tcx.get_diagnostic_name(i.def_id()) else { return };
let op = match name {
sym::noop_method_borrow => "borrow",
sym::noop_method_clone => "clone",
sym::noop_method_deref => "deref",
_ => return,
};
let receiver_ty = cx.typeck_results().expr_ty(receiver);
let expr_ty = cx.typeck_results().expr_ty_adjusted(expr);
let arg_adjustments = cx.typeck_results().expr_adjustments(receiver);
@ -129,11 +124,22 @@ impl<'tcx> LateLintPass<'tcx> for NoopMethodCall {
NoopMethodCallDiag { method: call.ident.name, receiver_ty, label: span },
);
} else {
cx.emit_spanned_lint(
SUSPICIOUS_DOUBLE_REF_OP,
span,
SuspiciousDoubleRefDiag { call: call.ident.name, ty: expr_ty, op },
)
match name {
// If `type_of(x) == T` and `x.borrow()` is used to get `&T`,
// then that should be allowed
sym::noop_method_borrow => return,
sym::noop_method_clone => cx.emit_spanned_lint(
SUSPICIOUS_DOUBLE_REF_OP,
span,
SuspiciousDoubleRefCloneDiag { ty: expr_ty },
),
sym::noop_method_deref => cx.emit_spanned_lint(
SUSPICIOUS_DOUBLE_REF_OP,
span,
SuspiciousDoubleRefDerefDiag { ty: expr_ty },
),
_ => return,
}
}
}
}