10 files changed, 133 insertions, 0 deletions
diff --git a/src/test/ui/cross/cross-borrow-trait.rs b/src/test/ui/cross/cross-borrow-trait.rs
new file mode 100644
index 000000000..180a75e3d
--- /dev/null
+++ b/src/test/ui/cross/cross-borrow-trait.rs
@@ -0,0 +1,13 @@
+// Test that cross-borrowing (implicitly converting from `Box<T>` to `&T`) is
+// forbidden when `T` is a trait.
+
+struct Foo;
+trait Trait { fn foo(&self) {} }
+impl Trait for Foo {}
+
+pub fn main() {
+    let x: Box<dyn Trait> = Box::new(Foo);
+    let _y: &dyn Trait = x; //~ ERROR E0308
+                            //~| expected reference `&dyn Trait`
+                            //~| found struct `Box<dyn Trait>`
+}
diff --git a/src/test/ui/cross/cross-borrow-trait.stderr b/src/test/ui/cross/cross-borrow-trait.stderr
new file mode 100644
index 000000000..81f309eae
--- /dev/null
+++ b/src/test/ui/cross/cross-borrow-trait.stderr
@@ -0,0 +1,14 @@
+error[E0308]: mismatched types
+  --> $DIR/cross-borrow-trait.rs:10:26
+   |
+LL |     let _y: &dyn Trait = x;
+   |             ----------   ^ expected `&dyn Trait`, found struct `Box`
+   |             |
+   |             expected due to this
+   |
+   = note: expected reference `&dyn Trait`
+                 found struct `Box<dyn Trait>`
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0308`.
diff --git a/src/test/ui/cross/cross-crate-macro-backtrace/auxiliary/extern_macro_crate.rs b/src/test/ui/cross/cross-crate-macro-backtrace/auxiliary/extern_macro_crate.rs
new file mode 100644
index 000000000..fbda3dbe9
--- /dev/null
+++ b/src/test/ui/cross/cross-crate-macro-backtrace/auxiliary/extern_macro_crate.rs
@@ -0,0 +1,13 @@
+#![crate_type = "dylib"]
+
+pub fn print(_args: std::fmt::Arguments) {}
+
+#[macro_export]
+macro_rules! myprint {
+    ($($arg:tt)*) => ($crate::print(format_args!($($arg)*)));
+}
+
+#[macro_export]
+macro_rules! myprintln {
+    ($fmt:expr) => (myprint!(concat!($fmt, "\n")));
+}
diff --git a/src/test/ui/cross/cross-crate-macro-backtrace/main.rs b/src/test/ui/cross/cross-crate-macro-backtrace/main.rs
new file mode 100644
index 000000000..f7d4330ab
--- /dev/null
+++ b/src/test/ui/cross/cross-crate-macro-backtrace/main.rs
@@ -0,0 +1,8 @@
+// aux-build:extern_macro_crate.rs
+#[macro_use(myprintln, myprint)]
+extern crate extern_macro_crate;
+
+fn main() {
+    myprintln!("{}");
+    //~^ ERROR in format string
+}
diff --git a/src/test/ui/cross/cross-crate-macro-backtrace/main.stderr b/src/test/ui/cross/cross-crate-macro-backtrace/main.stderr
new file mode 100644
index 000000000..5bd4ea97e
--- /dev/null
+++ b/src/test/ui/cross/cross-crate-macro-backtrace/main.stderr
@@ -0,0 +1,10 @@
+error: 1 positional argument in format string, but no arguments were given
+  --> $DIR/main.rs:6:5
+   |
+LL |     myprintln!("{}");
+   |     ^^^^^^^^^^^^^^^^
+   |
+   = note: this error originates in the macro `concat` which comes from the expansion of the macro `myprintln` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error: aborting due to previous error
+
diff --git a/src/test/ui/cross/cross-file-errors/main.rs b/src/test/ui/cross/cross-file-errors/main.rs
new file mode 100644
index 000000000..4219f892d
--- /dev/null
+++ b/src/test/ui/cross/cross-file-errors/main.rs
@@ -0,0 +1,7 @@
+#[macro_use]
+mod underscore;
+
+fn main() {
+    underscore!();
+    //~^ ERROR `_` can only be used on the left-hand side of an assignment
+}
diff --git a/src/test/ui/cross/cross-file-errors/main.stderr b/src/test/ui/cross/cross-file-errors/main.stderr
new file mode 100644
index 000000000..293a300ed
--- /dev/null
+++ b/src/test/ui/cross/cross-file-errors/main.stderr
@@ -0,0 +1,15 @@
+error: in expressions, `_` can only be used on the left-hand side of an assignment
+  --> $DIR/underscore.rs:8:9
+   |
+LL |         _
+   |         ^ `_` not allowed here
+   |
+  ::: $DIR/main.rs:5:5
+   |
+LL |     underscore!();
+   |     ------------- in this macro invocation
+   |
+   = note: this error originates in the macro `underscore` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error: aborting due to previous error
+
diff --git a/src/test/ui/cross/cross-file-errors/underscore.rs b/src/test/ui/cross/cross-file-errors/underscore.rs
new file mode 100644
index 000000000..76e72a93f
--- /dev/null
+++ b/src/test/ui/cross/cross-file-errors/underscore.rs
@@ -0,0 +1,10 @@
+// We want this file only so we can test cross-file error
+// messages, but we don't want it in an external crate.
+// ignore-test
+#![crate_type = "lib"]
+
+macro_rules! underscore {
+    () => (
+        _
+    )
+}
diff --git a/src/test/ui/cross/cross-fn-cache-hole.rs b/src/test/ui/cross/cross-fn-cache-hole.rs
new file mode 100644
index 000000000..c38a5001a
--- /dev/null
+++ b/src/test/ui/cross/cross-fn-cache-hole.rs
@@ -0,0 +1,31 @@
+// Check that when there are vacuous predicates in the environment
+// (which make a fn uncallable) we don't erroneously cache those and
+// then consider them satisfied elsewhere. The current technique for
+// doing this is to not use global caches when there is a chance that
+// the environment contains such a predicate.
+// We still error for `i32: Bar<u32>` pending #48214
+
+trait Foo<X,Y>: Bar<X> {
+}
+
+trait Bar<X> { }
+
+// We don't always check where clauses for sanity, but in this case
+// wfcheck does report an error here:
+fn vacuous<A>()
+    where i32: Foo<u32, A> //~ ERROR the trait bound `i32: Bar<u32>` is not satisfied
+{
+    // ... the original intention was to check that we don't use that
+    // vacuous where clause (which could never be satisfied) to accept
+    // the following line and then mess up calls elsewhere.
+    require::<i32, u32>();
+}
+
+fn require<A,B>()
+    where A: Bar<B>
+{
+}
+
+fn main() {
+    require::<i32, u32>();
+}
diff --git a/src/test/ui/cross/cross-fn-cache-hole.stderr b/src/test/ui/cross/cross-fn-cache-hole.stderr
new file mode 100644
index 000000000..7e15562b0
--- /dev/null
+++ b/src/test/ui/cross/cross-fn-cache-hole.stderr
@@ -0,0 +1,12 @@
+error[E0277]: the trait bound `i32: Bar<u32>` is not satisfied
+  --> $DIR/cross-fn-cache-hole.rs:16:11
+   |
+LL |     where i32: Foo<u32, A>
+   |           ^^^^^^^^^^^^^^^^ the trait `Bar<u32>` is not implemented for `i32`
+   |
+   = help: see issue #48214
+   = help: add `#![feature(trivial_bounds)]` to the crate attributes to enable
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0277`.