Review ignore external/proc macros

Author: RuairidhWilliamson

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::is_from_proc_macro;
 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_lint::{LateContext, LateLintPass, LintContext as _};
+use rustc_middle::lint::in_external_macro;
 use rustc_middle::ty::Visibility;
 use rustc_session::impl_lint_pass;
 use rustc_span::symbol::kw;
@@ -61,6 +63,7 @@ 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 self.msrv.meets(msrvs::UNDERSCORE_IMPORTS)
+            && !in_external_macro(cx.sess(), item.span)
             && let ItemKind::Use(path, UseKind::Single) = item.kind
             // Ignore imports that already use Underscore
             && item.ident.name != kw::Underscore
@@ -72,6 +75,7 @@ impl<'tcx> LateLintPass<'tcx> for AnonTraitImport {
             && cx.tcx.visibility(item.owner_id.def_id) == Visibility::Restricted(module.to_def_id())
             && let Some(last_segment) = path.segments.last()
             && let Some(snip) = snippet_opt(cx, last_segment.ident.span)
+            && !is_from_proc_macro(cx, &last_segment.ident)
         {
             let complete_span = last_segment.ident.span.to(item.ident.span);
             span_lint_and_sugg(

tests/ui/anon_trait_import.fixed

@@ -1,5 +1,10 @@
+//@aux-build:proc_macros.rs
+
 #![allow(unused)]
 #![warn(clippy::anon_trait_import)]
+#![feature(decl_macro)]
+
+extern crate proc_macros;
 
 fn main() {}
 
@@ -186,3 +191,50 @@ fn msrv_1_33() {
     use simple_trait::{MyStruct, MyTrait as _};
     MyStruct.do_things();
 }
+
+mod lint_inside_macro_expansion_bad {
+    macro_rules! foo {
+        () => {
+            use std::any::Any as _;
+            fn bar() {
+                "bar".type_id();
+            }
+        };
+    }
+
+    foo!();
+}
+
+mod macro_and_trait_same_name {
+    pub macro Foo() {}
+    pub trait Foo {
+        fn bar(&self);
+    }
+    impl Foo for () {
+        fn bar(&self) {}
+    }
+}
+
+fn call_macro_and_trait_good() {
+    // importing trait and macro but only using macro by path won't allow us to change this to
+    // `use macro_and_trait_same_name::Foo as _;`
+    use macro_and_trait_same_name::Foo;
+    Foo!();
+    ().bar();
+}
+
+proc_macros::external!(
+    fn ignore_inside_external_proc_macro() {
+        use std::any::Any;
+        "foo".type_id();
+    }
+);
+
+proc_macros::with_span!(
+    span
+
+    fn ignore_inside_with_span_proc_macro() {
+        use std::any::Any;
+        "foo".type_id();
+    }
+);

tests/ui/anon_trait_import.rs

@@ -1,5 +1,10 @@
+//@aux-build:proc_macros.rs
+
 #![allow(unused)]
 #![warn(clippy::anon_trait_import)]
+#![feature(decl_macro)]
+
+extern crate proc_macros;
 
 fn main() {}
 
@@ -186,3 +191,50 @@ fn msrv_1_33() {
     use simple_trait::{MyStruct, MyTrait};
     MyStruct.do_things();
 }
+
+mod lint_inside_macro_expansion_bad {
+    macro_rules! foo {
+        () => {
+            use std::any::Any;
+            fn bar() {
+                "bar".type_id();
+            }
+        };
+    }
+
+    foo!();
+}
+
+mod macro_and_trait_same_name {
+    pub macro Foo() {}
+    pub trait Foo {
+        fn bar(&self);
+    }
+    impl Foo for () {
+        fn bar(&self) {}
+    }
+}
+
+fn call_macro_and_trait_good() {
+    // importing trait and macro but only using macro by path won't allow us to change this to
+    // `use macro_and_trait_same_name::Foo as _;`
+    use macro_and_trait_same_name::Foo;
+    Foo!();
+    ().bar();
+}
+
+proc_macros::external!(
+    fn ignore_inside_external_proc_macro() {
+        use std::any::Any;
+        "foo".type_id();
+    }
+);
+
+proc_macros::with_span!(
+    span
+
+    fn ignore_inside_with_span_proc_macro() {
+        use std::any::Any;
+        "foo".type_id();
+    }
+);

tests/ui/anon_trait_import.stderr

@@ -1,5 +1,5 @@
 error: importing trait that is only used anonymously
-  --> tests/ui/anon_trait_import.rs:7:19
+  --> tests/ui/anon_trait_import.rs:12:19
    |
 LL |     use std::any::Any;
    |                   ^^^ help: use: `Any as _`
@@ -8,46 +8,57 @@ LL |     use std::any::Any;
    = help: to override `-D warnings` add `#[allow(clippy::anon_trait_import)]`
 
 error: importing trait that is only used anonymously
-  --> tests/ui/anon_trait_import.rs:26:26
+  --> tests/ui/anon_trait_import.rs:31:26
    |
 LL |     use std::any::{self, Any, TypeId};
    |                          ^^^ help: use: `Any as _`
 
 error: importing trait that is only used anonymously
-  --> tests/ui/anon_trait_import.rs:38:19
+  --> tests/ui/anon_trait_import.rs:43:19
    |
 LL |     use std::any::Any as MyAny;
    |                   ^^^^^^^^^^^^ help: use: `Any as _`
 
 error: importing trait that is only used anonymously
-  --> tests/ui/anon_trait_import.rs:44:20
+  --> tests/ui/anon_trait_import.rs:49:20
    |
 LL |     use std::any::{Any as MyAny, TypeId as MyTypeId};
    |                    ^^^^^^^^^^^^ help: use: `Any as _`
 
 error: importing trait that is only used anonymously
-  --> tests/ui/anon_trait_import.rs:67:23
+  --> tests/ui/anon_trait_import.rs:72:23
    |
 LL |         use std::any::Any;
    |                       ^^^ help: use: `Any as _`
 
 error: importing trait that is only used anonymously
-  --> tests/ui/anon_trait_import.rs:108:19
+  --> tests/ui/anon_trait_import.rs:113:19
    |
 LL |     use std::any::Any;
    |                   ^^^ help: use: `Any as _`
 
 error: importing trait that is only used anonymously
-  --> tests/ui/anon_trait_import.rs:127:19
+  --> tests/ui/anon_trait_import.rs:132:19
    |
 LL |     use std::any::Any;
    |                   ^^^ help: use: `Any as _`
 
 error: importing trait that is only used anonymously
-  --> tests/ui/anon_trait_import.rs:186:34
+  --> tests/ui/anon_trait_import.rs:191:34
    |
 LL |     use simple_trait::{MyStruct, MyTrait};
    |                                  ^^^^^^^ help: use: `MyTrait as _`
 
-error: aborting due to 8 previous errors
+error: importing trait that is only used anonymously
+  --> tests/ui/anon_trait_import.rs:198:27
+   |
+LL |             use std::any::Any;
+   |                           ^^^ help: use: `Any as _`
+...
+LL |     foo!();
+   |     ------ in this macro invocation
+   |
+   = note: this error originates in the macro `foo` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error: aborting due to 9 previous errors