auto merge of #15733 : sanxiyn/rust/use-from-type, r=alexcrichton

Importing from types was disallowed in #6462. Flag was set for paths whether it is a module or a type. Type flag was set when impl was seen. The problem is, for cross-crate situations, when reexport is involved, it is possible that impl is seen too late because metadata is loaded lazily.

Fix #15664.

2 files changed, 13 insertions, 0 deletions

diff --git a/src/test/auxiliary/use_from_trait_xc.rs b/src/test/auxiliary/use_from_trait_xc.rs
index 19e53fcc61a..8c547c28002 100644
--- a/src/test/auxiliary/use_from_trait_xc.rs
+++ b/src/test/auxiliary/use_from_trait_xc.rs
@@ -8,6 +8,8 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
+pub use self::sub::Bar;
+
 pub trait Trait {
     fn foo();
 }
@@ -17,3 +19,11 @@ struct Foo;
 impl Foo {
     pub fn new() {}
 }
+
+mod sub {
+    pub struct Bar;
+
+    impl Bar {
+        pub fn new() {}
+    }
+}
diff --git a/src/test/compile-fail/use-from-trait-xc.rs b/src/test/compile-fail/use-from-trait-xc.rs
index 8e197b901e6..cea85955d37 100644
--- a/src/test/compile-fail/use-from-trait-xc.rs
+++ b/src/test/compile-fail/use-from-trait-xc.rs
@@ -18,4 +18,7 @@ use use_from_trait_xc::Trait::foo;
 use use_from_trait_xc::Foo::new;
 //~^ ERROR unresolved import `use_from_trait_xc::Foo::new`. Cannot import from a trait or type imple
 
+use use_from_trait_xc::Bar::new;
+//~^ ERROR unresolved import `use_from_trait_xc::Bar::new`. Cannot import from a trait or type
+
 fn main() {}