[excessive_bools] lint trait functions even without bodies

Author: kraktus

clippy_lints/src/excessive_bools.rs

@@ -1,7 +1,7 @@
 use clippy_utils::diagnostics::span_lint_and_help;
 use clippy_utils::{get_parent_as_impl, has_repr_attr, is_bool};
 use rustc_hir::intravisit::FnKind;
-use rustc_hir::{Body, FnDecl, HirId, Item, ItemKind, Ty};
+use rustc_hir::{Body, FnDecl, HirId, Item, ItemKind, TraitFn, TraitItem, TraitItemKind, Ty};
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_session::{declare_tool_lint, impl_lint_pass};
 use rustc_span::Span;
@@ -114,7 +114,7 @@ impl ExcessiveBools {
     }
 
     fn check_fn_sig(&self, cx: &LateContext<'_>, fn_decl: &FnDecl<'_>, span: Span) {
-        if self.too_many_bools(fn_decl.inputs.iter(), Kind::Fn) {
+        if !span.from_expansion() && self.too_many_bools(fn_decl.inputs.iter(), Kind::Fn) {
             span_lint_and_help(
                 cx,
                 FN_PARAMS_EXCESSIVE_BOOLS,
@@ -152,6 +152,15 @@ impl<'tcx> LateLintPass<'tcx> for ExcessiveBools {
         }
     }
 
+    fn check_trait_item(&mut self, cx: &LateContext<'tcx>, trait_item: &'tcx TraitItem<'tcx>) {
+        // functions with a body are already checked by `check_fn`
+        if let TraitItemKind::Fn(fn_sig, TraitFn::Required(_)) = &trait_item.kind
+            && fn_sig.header.abi == Abi::Rust
+            {
+            self.check_fn_sig(cx, fn_sig.decl, fn_sig.span);
+        }
+    }
+
     fn check_fn(
         &mut self,
         cx: &LateContext<'tcx>,
@@ -163,7 +172,6 @@ impl<'tcx> LateLintPass<'tcx> for ExcessiveBools {
     ) {
         if let Some(fn_header) = fn_kind.header()
             && fn_header.abi == Abi::Rust
-            && !span.from_expansion()
             && get_parent_as_impl(cx.tcx, hir_id)
                 .map_or(true,
                     |impl_item| impl_item.of_trait.is_none()

tests/ui/fn_params_excessive_bools.rs

@@ -23,10 +23,12 @@ fn t(_: S, _: S, _: Box<S>, _: Vec<u32>, _: bool, _: bool, _: bool, _: bool) {}
 
 struct S;
 trait Trait {
+    // should warn for trait functions with and without body
     fn f(_: bool, _: bool, _: bool, _: bool);
     fn g(_: bool, _: bool, _: bool, _: Vec<u32>);
     #[allow(clippy::fn_params_excessive_bools)]
     fn h(_: bool, _: bool, _: bool, _: bool, _: bool, _: bool);
+    fn i(_: bool, _: bool, _: bool, _: bool) {}
 }
 
 impl S {

tests/ui/fn_params_excessive_bools.stderr

@@ -16,15 +16,31 @@ LL | fn t(_: S, _: S, _: Box<S>, _: Vec<u32>, _: bool, _: bool, _: bool, _: bool
    = help: consider refactoring bools into two-variant enums
 
 error: more than 3 bools in function parameters
-  --> $DIR/fn_params_excessive_bools.rs:33:5
+  --> $DIR/fn_params_excessive_bools.rs:27:5
+   |
+LL |     fn f(_: bool, _: bool, _: bool, _: bool);
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = help: consider refactoring bools into two-variant enums
+
+error: more than 3 bools in function parameters
+  --> $DIR/fn_params_excessive_bools.rs:31:5
+   |
+LL |     fn i(_: bool, _: bool, _: bool, _: bool) {}
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = help: consider refactoring bools into two-variant enums
+
+error: more than 3 bools in function parameters
+  --> $DIR/fn_params_excessive_bools.rs:35:5
    |
 LL |     fn f(&self, _: bool, _: bool, _: bool, _: bool) {}
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
    = help: consider refactoring bools into two-variant enums
 
 error: more than 3 bools in function parameters
-  --> $DIR/fn_params_excessive_bools.rs:48:5
+  --> $DIR/fn_params_excessive_bools.rs:50:5
    |
 LL | /     fn n(_: bool, _: u32, _: bool, _: Box<u32>, _: bool, _: bool) {
 LL | |         fn nn(_: bool, _: bool, _: bool, _: bool) {}
@@ -34,12 +50,12 @@ LL | |     }
    = help: consider refactoring bools into two-variant enums
 
 error: more than 3 bools in function parameters
-  --> $DIR/fn_params_excessive_bools.rs:49:9
+  --> $DIR/fn_params_excessive_bools.rs:51:9
    |
 LL |         fn nn(_: bool, _: bool, _: bool, _: bool) {}
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
    = help: consider refactoring bools into two-variant enums
 
-error: aborting due to 5 previous errors
+error: aborting due to 7 previous errors