From b87f5bc55a4dd4210c0d8bcd1ea68d26c75c75d0 Mon Sep 17 00:00:00 2001 From: Philipp Hansch Date: Mon, 4 Mar 2019 22:56:33 +0100 Subject: [PATCH 1/2] Don't trigger missing_const_for_fn in external macros As reported in #3841. Only fixes the part where it triggers on the `derive`. --- clippy_lints/src/missing_const_for_fn.rs | 4 ++-- tests/ui/missing_const_for_fn/cant_be_const.rs | 4 ++++ 2 files changed, 6 insertions(+), 2 deletions(-) diff --git a/clippy_lints/src/missing_const_for_fn.rs b/clippy_lints/src/missing_const_for_fn.rs index 00a3de0632f8..bd9e8ce8b8df 100644 --- a/clippy_lints/src/missing_const_for_fn.rs +++ b/clippy_lints/src/missing_const_for_fn.rs @@ -2,7 +2,7 @@ use crate::utils::{is_entrypoint_fn, span_lint}; use rustc::hir; use rustc::hir::intravisit::FnKind; use rustc::hir::{Body, Constness, FnDecl, HirId}; -use rustc::lint::{LateContext, LateLintPass, LintArray, LintPass}; +use rustc::lint::{in_external_macro, LateContext, LateLintPass, LintArray, LintPass}; use rustc::{declare_tool_lint, lint_array}; use rustc_mir::transform::qualify_min_const_fn::is_min_const_fn; use syntax_pos::Span; @@ -82,7 +82,7 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for MissingConstForFn { ) { let def_id = cx.tcx.hir().local_def_id_from_hir_id(hir_id); - if is_entrypoint_fn(cx, def_id) { + if in_external_macro(cx.tcx.sess, span) || is_entrypoint_fn(cx, def_id) { return; } diff --git a/tests/ui/missing_const_for_fn/cant_be_const.rs b/tests/ui/missing_const_for_fn/cant_be_const.rs index 36efe16b84f0..4a2e6adb8f06 100644 --- a/tests/ui/missing_const_for_fn/cant_be_const.rs +++ b/tests/ui/missing_const_for_fn/cant_be_const.rs @@ -55,3 +55,7 @@ trait Foo { 33 } } + +// Don't lint in external macros (derive) +#[derive(PartialEq, Eq)] +struct Point(isize, isize); From 15cba2e9563bd736a6d18028b43482698775c23d Mon Sep 17 00:00:00 2001 From: Philipp Hansch Date: Tue, 5 Mar 2019 08:11:55 +0100 Subject: [PATCH 2/2] Fix missing_const_for_fn for impl trait methods --- clippy_lints/src/missing_const_for_fn.rs | 15 ++++++++++++++- tests/ui/missing_const_for_fn/cant_be_const.rs | 9 +++++++++ 2 files changed, 23 insertions(+), 1 deletion(-) diff --git a/clippy_lints/src/missing_const_for_fn.rs b/clippy_lints/src/missing_const_for_fn.rs index bd9e8ce8b8df..633105ff60bb 100644 --- a/clippy_lints/src/missing_const_for_fn.rs +++ b/clippy_lints/src/missing_const_for_fn.rs @@ -1,4 +1,5 @@ use crate::utils::{is_entrypoint_fn, span_lint}; +use if_chain::if_chain; use rustc::hir; use rustc::hir::intravisit::FnKind; use rustc::hir::{Body, Constness, FnDecl, HirId}; @@ -95,7 +96,7 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for MissingConstForFn { } }, FnKind::Method(_, sig, ..) => { - if already_const(sig.header) { + if is_trait_method(cx, hir_id) || already_const(sig.header) { return; } }, @@ -114,6 +115,18 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for MissingConstForFn { } } +fn is_trait_method(cx: &LateContext<'_, '_>, hir_id: HirId) -> bool { + // Get the implemented trait for the current function + let parent_impl = cx.tcx.hir().get_parent_item(hir_id); + if_chain! { + if parent_impl != hir::CRATE_HIR_ID; + if let hir::Node::Item(item) = cx.tcx.hir().get_by_hir_id(parent_impl); + if let hir::ItemKind::Impl(_, _, _, _, Some(_trait_ref), _, _) = &item.node; + then { return true; } + } + false +} + // We don't have to lint on something that's already `const` fn already_const(header: hir::FnHeader) -> bool { header.constness == Constness::Const diff --git a/tests/ui/missing_const_for_fn/cant_be_const.rs b/tests/ui/missing_const_for_fn/cant_be_const.rs index 4a2e6adb8f06..115cc954dc78 100644 --- a/tests/ui/missing_const_for_fn/cant_be_const.rs +++ b/tests/ui/missing_const_for_fn/cant_be_const.rs @@ -59,3 +59,12 @@ trait Foo { // Don't lint in external macros (derive) #[derive(PartialEq, Eq)] struct Point(isize, isize); + +impl std::ops::Add for Point { + type Output = Self; + + // Don't lint in trait impls of derived methods + fn add(self, other: Self) -> Self { + Point(self.0 + other.0, self.1 + other.1) + } +}