diff --git a/clippy_lints/src/trivially_copy_pass_by_ref.rs b/clippy_lints/src/trivially_copy_pass_by_ref.rs
index 61a2a9ded44..2929752bbb2 100644
--- a/clippy_lints/src/trivially_copy_pass_by_ref.rs
+++ b/clippy_lints/src/trivially_copy_pass_by_ref.rs
@@ -18,12 +18,13 @@ use crate::rustc::lint::{LateContext, LateLintPass, LintArray, LintPass};
use crate::rustc::{declare_tool_lint, lint_array};
use if_chain::if_chain;
use crate::rustc::ty::TyKind;
+use crate::rustc::ty::FnSig;
use crate::rustc::session::config::Config as SessionConfig;
use crate::rustc_target::spec::abi::Abi;
use crate::rustc_target::abi::LayoutOf;
use crate::syntax::ast::NodeId;
use crate::syntax_pos::Span;
-use crate::utils::{in_macro, is_copy, is_self, span_lint_and_sugg, snippet};
+use crate::utils::{in_macro, is_copy, is_self_ty, span_lint_and_sugg, snippet};
/// **What it does:** Checks for functions taking arguments by reference, where
/// the argument type is `Copy` and small enough to be more efficient to always
@@ -67,7 +68,7 @@ pub struct TriviallyCopyPassByRef {
limit: u64,
}
-impl TriviallyCopyPassByRef {
+impl<'a, 'tcx> TriviallyCopyPassByRef {
pub fn new(limit: Option<u64>, target: &SessionConfig) -> Self {
let limit = limit.unwrap_or_else(|| {
let bit_width = target.usize_ty.bit_width().expect("usize should have a width") as u64;
@@ -80,6 +81,83 @@ impl TriviallyCopyPassByRef {
});
Self { limit }
}
+
+ fn check_trait_method(
+ &mut self,
+ cx: &LateContext<'_, 'tcx>,
+ item: &TraitItemRef
+ ) {
+ let method_def_id = cx.tcx.hir.local_def_id(item.id.node_id);
+ let method_sig = cx.tcx.fn_sig(method_def_id);
+ let method_sig = cx.tcx.erase_late_bound_regions(&method_sig);
+
+ let decl = match cx.tcx.hir.fn_decl(item.id.node_id) {
+ Some(b) => b,
+ None => return,
+ };
+
+ self.check_poly_fn(cx, &decl, &method_sig, None);
+ }
+
+ fn check_poly_fn(
+ &mut self,
+ cx: &LateContext<'_, 'tcx>,
+ decl: &FnDecl,
+ sig: &FnSig<'tcx>,
+ span: Option<Span>,
+ ) {
+ // Use lifetimes to determine if we're returning a reference to the
+ // argument. In that case we can't switch to pass-by-value as the
+ // argument will not live long enough.
+ let output_lts = match sig.output().sty {
+ TyKind::Ref(output_lt, _, _) => vec![output_lt],
+ TyKind::Adt(_, substs) => substs.regions().collect(),
+ _ => vec![],
+ };
+
+ for (input, &ty) in decl.inputs.iter().zip(sig.inputs()) {
+ // All spans generated from a proc-macro invocation are the same...
+ match span {
+ Some(s) if s == input.span => return,
+ _ => (),
+ }
+
+ if_chain! {
+ if let TyKind::Ref(input_lt, ty, Mutability::MutImmutable) = ty.sty;
+ if !output_lts.contains(&input_lt);
+ if is_copy(cx, ty);
+ if let Some(size) = cx.layout_of(ty).ok().map(|l| l.size.bytes());
+ if size <= self.limit;
+ if let hir::TyKind::Rptr(_, MutTy { ty: ref decl_ty, .. }) = input.node;
+ then {
+ let value_type = if is_self_ty(decl_ty) {
+ "self".into()
+ } else {
+ snippet(cx, decl_ty.span, "_").into()
+ };
+ span_lint_and_sugg(
+ cx,
+ TRIVIALLY_COPY_PASS_BY_REF,
+ input.span,
+ "this argument is passed by reference, but would be more efficient if passed by value",
+ "consider passing by value instead",
+ value_type);
+ }
+ }
+ }
+ }
+
+ fn check_trait_items(
+ &mut self,
+ cx: &LateContext<'_, '_>,
+ trait_items: &[TraitItemRef]
+ ) {
+ for item in trait_items {
+ if let AssociatedItemKind::Method{..} = item.kind {
+ self.check_trait_method(cx, item);
+ }
+ }
+ }
}
impl LintPass for TriviallyCopyPassByRef {
@@ -89,12 +167,21 @@ impl LintPass for TriviallyCopyPassByRef {
}
impl<'a, 'tcx> LateLintPass<'a, 'tcx> for TriviallyCopyPassByRef {
+ fn check_item(&mut self, cx: &LateContext<'a, 'tcx>, item: &'tcx Item) {
+ if in_macro(item.span) {
+ return;
+ }
+ if let ItemKind::Trait(_, _, _, _, ref trait_items) = item.node {
+ self.check_trait_items(cx, trait_items);
+ }
+ }
+
fn check_fn(
&mut self,
cx: &LateContext<'a, 'tcx>,
kind: FnKind<'tcx>,
decl: &'tcx FnDecl,
- body: &'tcx Body,
+ _body: &'tcx Body,
span: Span,
node_id: NodeId,
) {
@@ -131,43 +218,6 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for TriviallyCopyPassByRef {
let fn_sig = cx.tcx.fn_sig(fn_def_id);
let fn_sig = cx.tcx.erase_late_bound_regions(&fn_sig);
- // Use lifetimes to determine if we're returning a reference to the
- // argument. In that case we can't switch to pass-by-value as the
- // argument will not live long enough.
- let output_lts = match fn_sig.output().sty {
- TyKind::Ref(output_lt, _, _) => vec![output_lt],
- TyKind::Adt(_, substs) => substs.regions().collect(),
- _ => vec![],
- };
-
- for ((input, &ty), arg) in decl.inputs.iter().zip(fn_sig.inputs()).zip(&body.arguments) {
- // All spans generated from a proc-macro invocation are the same...
- if span == input.span {
- return;
- }
-
- if_chain! {
- if let TyKind::Ref(input_lt, ty, Mutability::MutImmutable) = ty.sty;
- if !output_lts.contains(&input_lt);
- if is_copy(cx, ty);
- if let Some(size) = cx.layout_of(ty).ok().map(|l| l.size.bytes());
- if size <= self.limit;
- if let hir::TyKind::Rptr(_, MutTy { ty: ref decl_ty, .. }) = input.node;
- then {
- let value_type = if is_self(arg) {
- "self".into()
- } else {
- snippet(cx, decl_ty.span, "_").into()
- };
- span_lint_and_sugg(
- cx,
- TRIVIALLY_COPY_PASS_BY_REF,
- input.span,
- "this argument is passed by reference, but would be more efficient if passed by value",
- "consider passing by value instead",
- value_type);
- }
- }
- }
+ self.check_poly_fn(cx, decl, &fn_sig, Some(span));
}
}
diff --git a/tests/ui/trivially_copy_pass_by_ref.rs b/tests/ui/trivially_copy_pass_by_ref.rs
index cebe15b2cc8..2a0dc22bfef 100644
--- a/tests/ui/trivially_copy_pass_by_ref.rs
+++ b/tests/ui/trivially_copy_pass_by_ref.rs
@@ -18,6 +18,11 @@ struct Foo(u32);
#[derive(Copy, Clone)]
struct Bar([u8; 24]);
+#[derive(Copy, Clone)]
+pub struct Color {
+ pub r: u8, pub g: u8, pub b: u8, pub a: u8,
+}
+
struct FooRef<'a> {
foo: &'a Foo,
}
@@ -80,6 +85,20 @@ impl Bar {
}
}
+trait MyTrait {
+ fn trait_method(&self, _foo: &Foo);
+}
+
+pub trait MyTrait2 {
+ fn trait_method2(&self, _color: &Color);
+}
+
+impl MyTrait for Foo {
+ fn trait_method(&self, _foo: &Foo) {
+ unimplemented!()
+ }
+}
+
fn main() {
let (mut foo, bar) = (Foo(0), Bar([0; 24]));
let (mut a, b, c, x, y, z) = (0, 0, Bar([0; 24]), 0, Foo(0), 0);
diff --git a/tests/ui/trivially_copy_pass_by_ref.stderr b/tests/ui/trivially_copy_pass_by_ref.stderr
index 2026d4c00d8..3fb577d3edb 100644
--- a/tests/ui/trivially_copy_pass_by_ref.stderr
+++ b/tests/ui/trivially_copy_pass_by_ref.stderr
@@ -1,82 +1,94 @@
error: this argument is passed by reference, but would be more efficient if passed by value
- --> $DIR/trivially_copy_pass_by_ref.rs:52:11
+ --> $DIR/trivially_copy_pass_by_ref.rs:57:11
|
-52 | fn bad(x: &u32, y: &Foo, z: &Baz) {
+57 | fn bad(x: &u32, y: &Foo, z: &Baz) {
| ^^^^ help: consider passing by value instead: `u32`
|
= note: `-D clippy::trivially-copy-pass-by-ref` implied by `-D warnings`
error: this argument is passed by reference, but would be more efficient if passed by value
- --> $DIR/trivially_copy_pass_by_ref.rs:52:20
+ --> $DIR/trivially_copy_pass_by_ref.rs:57:20
|
-52 | fn bad(x: &u32, y: &Foo, z: &Baz) {
+57 | fn bad(x: &u32, y: &Foo, z: &Baz) {
| ^^^^ help: consider passing by value instead: `Foo`
error: this argument is passed by reference, but would be more efficient if passed by value
- --> $DIR/trivially_copy_pass_by_ref.rs:52:29
+ --> $DIR/trivially_copy_pass_by_ref.rs:57:29
|
-52 | fn bad(x: &u32, y: &Foo, z: &Baz) {
+57 | fn bad(x: &u32, y: &Foo, z: &Baz) {
| ^^^^ help: consider passing by value instead: `Baz`
error: this argument is passed by reference, but would be more efficient if passed by value
- --> $DIR/trivially_copy_pass_by_ref.rs:62:12
+ --> $DIR/trivially_copy_pass_by_ref.rs:67:12
|
-62 | fn bad(&self, x: &u32, y: &Foo, z: &Baz) {
+67 | fn bad(&self, x: &u32, y: &Foo, z: &Baz) {
| ^^^^^ help: consider passing by value instead: `self`
error: this argument is passed by reference, but would be more efficient if passed by value
- --> $DIR/trivially_copy_pass_by_ref.rs:62:22
+ --> $DIR/trivially_copy_pass_by_ref.rs:67:22
|
-62 | fn bad(&self, x: &u32, y: &Foo, z: &Baz) {
+67 | fn bad(&self, x: &u32, y: &Foo, z: &Baz) {
| ^^^^ help: consider passing by value instead: `u32`
error: this argument is passed by reference, but would be more efficient if passed by value
- --> $DIR/trivially_copy_pass_by_ref.rs:62:31
+ --> $DIR/trivially_copy_pass_by_ref.rs:67:31
|
-62 | fn bad(&self, x: &u32, y: &Foo, z: &Baz) {
+67 | fn bad(&self, x: &u32, y: &Foo, z: &Baz) {
| ^^^^ help: consider passing by value instead: `Foo`
error: this argument is passed by reference, but would be more efficient if passed by value
- --> $DIR/trivially_copy_pass_by_ref.rs:62:40
+ --> $DIR/trivially_copy_pass_by_ref.rs:67:40
|
-62 | fn bad(&self, x: &u32, y: &Foo, z: &Baz) {
+67 | fn bad(&self, x: &u32, y: &Foo, z: &Baz) {
| ^^^^ help: consider passing by value instead: `Baz`
error: this argument is passed by reference, but would be more efficient if passed by value
- --> $DIR/trivially_copy_pass_by_ref.rs:65:16
+ --> $DIR/trivially_copy_pass_by_ref.rs:70:16
|
-65 | fn bad2(x: &u32, y: &Foo, z: &Baz) {
+70 | fn bad2(x: &u32, y: &Foo, z: &Baz) {
| ^^^^ help: consider passing by value instead: `u32`
error: this argument is passed by reference, but would be more efficient if passed by value
- --> $DIR/trivially_copy_pass_by_ref.rs:65:25
+ --> $DIR/trivially_copy_pass_by_ref.rs:70:25
|
-65 | fn bad2(x: &u32, y: &Foo, z: &Baz) {
+70 | fn bad2(x: &u32, y: &Foo, z: &Baz) {
| ^^^^ help: consider passing by value instead: `Foo`
error: this argument is passed by reference, but would be more efficient if passed by value
- --> $DIR/trivially_copy_pass_by_ref.rs:65:34
+ --> $DIR/trivially_copy_pass_by_ref.rs:70:34
|
-65 | fn bad2(x: &u32, y: &Foo, z: &Baz) {
+70 | fn bad2(x: &u32, y: &Foo, z: &Baz) {
| ^^^^ help: consider passing by value instead: `Baz`
error: this argument is passed by reference, but would be more efficient if passed by value
- --> $DIR/trivially_copy_pass_by_ref.rs:79:16
+ --> $DIR/trivially_copy_pass_by_ref.rs:84:16
|
-79 | fn bad2(x: &u32, y: &Foo, z: &Baz) {
+84 | fn bad2(x: &u32, y: &Foo, z: &Baz) {
| ^^^^ help: consider passing by value instead: `u32`
error: this argument is passed by reference, but would be more efficient if passed by value
- --> $DIR/trivially_copy_pass_by_ref.rs:79:25
+ --> $DIR/trivially_copy_pass_by_ref.rs:84:25
|
-79 | fn bad2(x: &u32, y: &Foo, z: &Baz) {
+84 | fn bad2(x: &u32, y: &Foo, z: &Baz) {
| ^^^^ help: consider passing by value instead: `Foo`
error: this argument is passed by reference, but would be more efficient if passed by value
- --> $DIR/trivially_copy_pass_by_ref.rs:79:34
+ --> $DIR/trivially_copy_pass_by_ref.rs:84:34
|
-79 | fn bad2(x: &u32, y: &Foo, z: &Baz) {
+84 | fn bad2(x: &u32, y: &Foo, z: &Baz) {
| ^^^^ help: consider passing by value instead: `Baz`
-error: aborting due to 13 previous errors
+error: this argument is passed by reference, but would be more efficient if passed by value
+ --> $DIR/trivially_copy_pass_by_ref.rs:89:34
+ |
+89 | fn trait_method(&self, _foo: &Foo);
+ | ^^^^ help: consider passing by value instead: `Foo`
+
+error: this argument is passed by reference, but would be more efficient if passed by value
+ --> $DIR/trivially_copy_pass_by_ref.rs:93:37
+ |
+93 | fn trait_method2(&self, _color: &Color);
+ | ^^^^^^ help: consider passing by value instead: `Color`
+
+error: aborting due to 15 previous errors