resolve: Simplify collection of traits in scope

src/test/ui/hygiene/traits-in-scope.rs

@@ -0,0 +1,53 @@
+// Macros with def-site hygiene still bring traits into scope.
+// It is not clear whether this is desirable behavior or not.
+// It is also not clear how to prevent it if it is not desirable.
+
+// check-pass
+
+#![feature(decl_macro)]
+#![feature(trait_alias)]
+
+mod traits {
+    pub trait Trait1 {
+        fn simple_import(&self) {}
+    }
+    pub trait Trait2 {
+        fn renamed_import(&self) {}
+    }
+    pub trait Trait3 {
+        fn underscore_import(&self) {}
+    }
+    pub trait Trait4 {
+        fn trait_alias(&self) {}
+    }
+
+    impl Trait1 for () {}
+    impl Trait2 for () {}
+    impl Trait3 for () {}
+    impl Trait4 for () {}
+}
+
+macro m1() {
+    use traits::Trait1;
+}
+macro m2() {
+    use traits::Trait2 as Alias;
+}
+macro m3() {
+    use traits::Trait3 as _;
+}
+macro m4() {
+    trait Alias = traits::Trait4;
+}
+
+fn main() {
+    m1!();
+    m2!();
+    m3!();
+    m4!();
+
+    ().simple_import();
+    ().renamed_import();
+    ().underscore_import();
+    ().trait_alias();
+}

src/test/ui/underscore-imports/hygiene.rs

@@ -1,5 +1,6 @@
-// Make sure that underscore imports have the same hygiene considerations as
-// other imports.
+// Make sure that underscore imports have the same hygiene considerations as other imports.
+
+// check-pass
 
 #![feature(decl_macro)]
 
@@ -7,7 +8,6 @@ mod x {
     pub use std::ops::Deref as _;
 }
 
-
 macro glob_import() {
     pub use crate::x::*;
 }
@@ -35,6 +35,6 @@ fn main() {
     use crate::z::*;
     glob_import!();
     underscore_import!();
-    (&()).deref();              //~ ERROR no method named `deref`
-    (&mut ()).deref_mut();      //~ ERROR no method named `deref_mut`
+    (&()).deref();
+    (&mut ()).deref_mut();
 }

src/test/ui/underscore-imports/hygiene.stderr

@@ -1,27 +0,0 @@
-error[E0599]: no method named `deref` found for reference `&()` in the current scope
-  --> $DIR/hygiene.rs:38:11
-   |
-LL |     (&()).deref();
-   |           ^^^^^ method not found in `&()`
-   |
-   = help: items from traits can only be used if the trait is in scope
-help: the following trait is implemented but not in scope; perhaps add a `use` for it:
-   |
-LL | use std::ops::Deref;
-   |
-
-error[E0599]: no method named `deref_mut` found for mutable reference `&mut ()` in the current scope
-  --> $DIR/hygiene.rs:39:15
-   |
-LL |     (&mut ()).deref_mut();
-   |               ^^^^^^^^^ method not found in `&mut ()`
-   |
-   = help: items from traits can only be used if the trait is in scope
-help: the following trait is implemented but not in scope; perhaps add a `use` for it:
-   |
-LL | use std::ops::DerefMut;
-   |
-
-error: aborting due to 2 previous errors
-
-For more information about this error, try `rustc --explain E0599`.