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Use get_diagnostic_name more

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This commit is contained in:
Cameron Steffen 2021-11-16 13:12:38 -06:00
parent d914f17ca7
commit dec40530f7
6 changed files with 73 additions and 74 deletions
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62
compiler/rustc_lint/src/noop_method_call.rs
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@ -75,38 +75,36 @@ impl<'tcx> LateLintPass<'tcx> for NoopMethodCall {
_ => return,
};
// (Re)check that it implements the noop diagnostic.
for s in [sym::noop_method_clone, sym::noop_method_deref, sym::noop_method_borrow].iter() {
if cx.tcx.is_diagnostic_item(*s, i.def_id()) {
let method = &call.ident.name;
let receiver = &elements[0];
let receiver_ty = cx.typeck_results().expr_ty(receiver);
let expr_ty = cx.typeck_results().expr_ty_adjusted(expr);
if receiver_ty != expr_ty {
// This lint will only trigger if the receiver type and resulting expression \
// type are the same, implying that the method call is unnecessary.
return;
}
let expr_span = expr.span;
let note = format!(
"the type `{:?}` which `{}` is being called on is the same as \
the type returned from `{}`, so the method call does not do \
anything and can be removed",
receiver_ty, method, method,
);
let span = expr_span.with_lo(receiver.span.hi());
cx.struct_span_lint(NOOP_METHOD_CALL, span, |lint| {
let method = &call.ident.name;
let message = format!(
"call to `.{}()` on a reference in this situation does nothing",
&method,
);
lint.build(&message)
.span_label(span, "unnecessary method call")
.note(&note)
.emit()
});
}
let Some(name) = cx.tcx.get_diagnostic_name(i.def_id()) else { return };
if !matches!(
name,
sym::noop_method_borrow | sym::noop_method_clone | sym::noop_method_deref
) {
return;
}
let method = &call.ident.name;
let receiver = &elements[0];
let receiver_ty = cx.typeck_results().expr_ty(receiver);
let expr_ty = cx.typeck_results().expr_ty_adjusted(expr);
if receiver_ty != expr_ty {
// This lint will only trigger if the receiver type and resulting expression \
// type are the same, implying that the method call is unnecessary.
return;
}
let expr_span = expr.span;
let note = format!(
"the type `{:?}` which `{}` is being called on is the same as \
the type returned from `{}`, so the method call does not do \
anything and can be removed",
receiver_ty, method, method,
);
let span = expr_span.with_lo(receiver.span.hi());
cx.struct_span_lint(NOOP_METHOD_CALL, span, |lint| {
let method = &call.ident.name;
let message =
format!("call to `.{}()` on a reference in this situation does nothing", &method,);
lint.build(&message).span_label(span, "unnecessary method call").note(&note).emit()
});
}
}