Review add msrv check

Author: RuairidhWilliamson

clippy_config/src/msrvs.rs

@@ -48,6 +48,7 @@ msrv_aliases! {
     1,36,0 { ITERATOR_COPIED }
     1,35,0 { OPTION_COPIED, RANGE_CONTAINS }
     1,34,0 { TRY_FROM }
+    1,33,0 { UNDERSCORE_IMPORTS }
     1,30,0 { ITERATOR_FIND_MAP, TOOL_ATTRIBUTES }
     1,29,0 { ITER_FLATTEN }
     1,28,0 { FROM_BOOL }

clippy_lints/src/anon_trait_import.rs

@@ -1,11 +1,13 @@
+use clippy_config::msrvs::{self, Msrv};
+use clippy_config::Conf;
 use clippy_utils::diagnostics::span_lint_and_sugg;
 use clippy_utils::source::snippet_opt;
 use rustc_errors::Applicability;
 use rustc_hir::def::{DefKind, Res};
 use rustc_hir::{Item, ItemKind, UseKind};
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_middle::ty::Visibility;
-use rustc_session::declare_lint_pass;
+use rustc_session::impl_lint_pass;
 use rustc_span::symbol::kw;
 
 declare_clippy_lint! {
@@ -42,11 +44,24 @@ declare_clippy_lint! {
     "use items that import a trait but only use it anonymously"
 }
 
-declare_lint_pass!(AnonTraitImport => [ANON_TRAIT_IMPORT]);
+pub struct AnonTraitImport {
+    msrv: Msrv,
+}
+
+impl AnonTraitImport {
+    pub fn new(conf: &'static Conf) -> Self {
+        Self {
+            msrv: conf.msrv.clone(),
+        }
+    }
+}
+
+impl_lint_pass!(AnonTraitImport => [ANON_TRAIT_IMPORT]);
 
 impl<'tcx> LateLintPass<'tcx> for AnonTraitImport {
     fn check_item(&mut self, cx: &LateContext<'tcx>, item: &'tcx Item<'tcx>) {
-        if let ItemKind::Use(path, UseKind::Single) = item.kind
+        if self.msrv.meets(msrvs::UNDERSCORE_IMPORTS)
+            && let ItemKind::Use(path, UseKind::Single) = item.kind
             // Ignore imports that already use Underscore
             && item.ident.name != kw::Underscore
             // Only check traits
@@ -70,4 +85,6 @@ impl<'tcx> LateLintPass<'tcx> for AnonTraitImport {
             );
         }
     }
+
+    extract_msrv_attr!(LateContext);
 }

clippy_lints/src/lib.rs

@@ -938,6 +938,6 @@ pub fn register_lints(store: &mut rustc_lint::LintStore, conf: &'static Conf) {
     store.register_early_pass(|| Box::new(cfg_not_test::CfgNotTest));
     store.register_late_pass(|_| Box::new(zombie_processes::ZombieProcesses));
     store.register_late_pass(|_| Box::new(pointers_in_nomem_asm_block::PointersInNomemAsmBlock));
-    store.register_late_pass(|_| Box::new(anon_trait_import::AnonTraitImport));
+    store.register_late_pass(move |_| Box::new(anon_trait_import::AnonTraitImport::new(conf)));
     // add lints here, do not remove this comment, it's used in `new_lint`
 }

tests/ui/anon_trait_import.fixed

@@ -161,3 +161,28 @@ mod nested_mod_used_good5 {
         }
     }
 }
+
+mod simple_trait {
+    pub trait MyTrait {
+        fn do_things(&self);
+    }
+
+    pub struct MyStruct;
+
+    impl MyTrait for MyStruct {
+        fn do_things(&self) {}
+    }
+}
+
+// Underscore imports were stabilized in 1.33
+#[clippy::msrv = "1.32"]
+fn msrv_1_32() {
+    use simple_trait::{MyStruct, MyTrait};
+    MyStruct.do_things();
+}
+
+#[clippy::msrv = "1.33"]
+fn msrv_1_33() {
+    use simple_trait::{MyStruct, MyTrait as _};
+    MyStruct.do_things();
+}

tests/ui/anon_trait_import.rs

@@ -161,3 +161,28 @@ mod nested_mod_used_good5 {
         }
     }
 }
+
+mod simple_trait {
+    pub trait MyTrait {
+        fn do_things(&self);
+    }
+
+    pub struct MyStruct;
+
+    impl MyTrait for MyStruct {
+        fn do_things(&self) {}
+    }
+}
+
+// Underscore imports were stabilized in 1.33
+#[clippy::msrv = "1.32"]
+fn msrv_1_32() {
+    use simple_trait::{MyStruct, MyTrait};
+    MyStruct.do_things();
+}
+
+#[clippy::msrv = "1.33"]
+fn msrv_1_33() {
+    use simple_trait::{MyStruct, MyTrait};
+    MyStruct.do_things();
+}

tests/ui/anon_trait_import.stderr

@@ -43,5 +43,11 @@ error: importing trait that is only used anonymously
 LL |     use std::any::Any;
    |                   ^^^ help: use: `Any as _`
 
-error: aborting due to 7 previous errors
+error: importing trait that is only used anonymously
+  --> tests/ui/anon_trait_import.rs:186:34
+   |
+LL |     use simple_trait::{MyStruct, MyTrait};
+   |                                  ^^^^^^^ help: use: `MyTrait as _`
+
+error: aborting due to 8 previous errors