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Add suggestion to needless_borrow

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This commit is contained in:
topecongiro 2017-09-16 11:27:24 +09:00
parent f64bae4ae3
commit 197664e989
1 changed files with 21 additions and 6 deletions
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27
clippy_lints/src/needless_borrow.rs
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@ -6,7 +6,7 @@ use rustc::lint::*;
use rustc::hir::{BindingAnnotation, Expr, ExprAddrOf, MutImmutable, Pat, PatKind}; use rustc::hir::{BindingAnnotation, Expr, ExprAddrOf, MutImmutable, Pat, PatKind};
use rustc::ty; use rustc::ty;
use rustc::ty::adjustment::{Adjust, Adjustment}; use rustc::ty::adjustment::{Adjust, Adjustment};
use utils::{in_macro, span_lint}; use utils::{in_macro, snippet_opt, span_lint_and_then};
/// **What it does:** Checks for address of operations (`&`) that are going to /// **What it does:** Checks for address of operations (`&`) that are going to
/// be dereferenced immediately by the compiler. /// be dereferenced immediately by the compiler.
@ -54,12 +54,17 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for NeedlessBorrow {
.. ..
}] = *adj3 }] = *adj3
{ {
span_lint( span_lint_and_then(
cx, cx,
NEEDLESS_BORROW, NEEDLESS_BORROW,
e.span, e.span,
"this expression borrows a reference that is immediately dereferenced by the \ "this expression borrows a reference that is immediately dereferenced \
compiler", by the compiler",
|db| {
if let Some(snippet) = snippet_opt(cx, inner.span) {
db.span_suggestion(e.span, "change this to", snippet);
}
}
); );
} }
} }
@ -71,14 +76,24 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for NeedlessBorrow {
return; return;
} }
if_let_chain! {[ if_let_chain! {[
let PatKind::Binding(BindingAnnotation::Ref, _, _, _) = pat.node, let PatKind::Binding(BindingAnnotation::Ref, _, name, _) = pat.node,
let ty::TyRef(_, ref tam) = cx.tables.pat_ty(pat).sty, let ty::TyRef(_, ref tam) = cx.tables.pat_ty(pat).sty,
tam.mutbl == MutImmutable, tam.mutbl == MutImmutable,
let ty::TyRef(_, ref tam) = tam.ty.sty, let ty::TyRef(_, ref tam) = tam.ty.sty,
// only lint immutable refs, because borrowed `&mut T` cannot be moved out // only lint immutable refs, because borrowed `&mut T` cannot be moved out
tam.mutbl == MutImmutable, tam.mutbl == MutImmutable,
], { ], {
span_lint(cx, NEEDLESS_BORROW, pat.span, "this pattern creates a reference to a reference") span_lint_and_then(
cx,
NEEDLESS_BORROW,
pat.span,
"this pattern creates a reference to a reference",
|db| {
if let Some(snippet) = snippet_opt(cx, name.span) {
db.span_suggestion(pat.span, "change this to", snippet);
}
}
)
}} }}
} }
} }