Auto merge of #67874 - Dylan-DPC:rollup-xy6bkoe, r=Dylan-DPC

Rollup of 4 pull requests

Successful merges:

 - #67137 (libstd uses `core::panic::Location` where possible.)
 - #67709 (Introduce an option for disabling deduplication of diagnostics)
 - #67775 (Make "use $crate" a hard error)
 - #67812 (Tweak and extend internal BTreeMap documentation, including debug asserts.)

Failed merges:

r? @ghost

13 files changed, 71 insertions, 29 deletions

diff --git a/src/test/mir-opt/retain-never-const.rs b/src/test/mir-opt/retain-never-const.rs
index 04394dcdf13..8e9bae8569f 100644
--- a/src/test/mir-opt/retain-never-const.rs
+++ b/src/test/mir-opt/retain-never-const.rs
@@ -6,6 +6,7 @@
 
 #![feature(const_panic)]
 #![feature(never_type)]
+#![warn(const_err)]
 
 struct PrintName<T>(T);
 
diff --git a/src/test/ui/consts/miri_unleashed/mutable_const2.stderr b/src/test/ui/consts/miri_unleashed/mutable_const2.stderr
index 2212b7d75d2..3493b7c54c4 100644
--- a/src/test/ui/consts/miri_unleashed/mutable_const2.stderr
+++ b/src/test/ui/consts/miri_unleashed/mutable_const2.stderr
@@ -10,7 +10,7 @@ error: internal compiler error: mutable allocation in constant
 LL | const MUTABLE_BEHIND_RAW: *mut i32 = &UnsafeCell::new(42) as *const _ as *mut _;
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
-thread 'rustc' panicked at 'no errors encountered even though `delay_span_bug` issued', src/librustc_errors/lib.rs:345:17
+thread 'rustc' panicked at 'no errors encountered even though `delay_span_bug` issued', src/librustc_errors/lib.rs:347:17
 note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace.
 
 error: internal compiler error: unexpected panic
diff --git a/src/test/ui/deduplicate-diagnostics.deduplicate.stderr b/src/test/ui/deduplicate-diagnostics.deduplicate.stderr
new file mode 100644
index 00000000000..1acfce50622
--- /dev/null
+++ b/src/test/ui/deduplicate-diagnostics.deduplicate.stderr
@@ -0,0 +1,8 @@
+error: cannot find derive macro `Unresolved` in this scope
+  --> $DIR/deduplicate-diagnostics.rs:4:10
+   |
+LL | #[derive(Unresolved)]
+   |          ^^^^^^^^^^
+
+error: aborting due to previous error
+
diff --git a/src/test/ui/deduplicate-diagnostics.duplicate.stderr b/src/test/ui/deduplicate-diagnostics.duplicate.stderr
new file mode 100644
index 00000000000..325da3b5d91
--- /dev/null
+++ b/src/test/ui/deduplicate-diagnostics.duplicate.stderr
@@ -0,0 +1,14 @@
+error: cannot find derive macro `Unresolved` in this scope
+  --> $DIR/deduplicate-diagnostics.rs:4:10
+   |
+LL | #[derive(Unresolved)]
+   |          ^^^^^^^^^^
+
+error: cannot find derive macro `Unresolved` in this scope
+  --> $DIR/deduplicate-diagnostics.rs:4:10
+   |
+LL | #[derive(Unresolved)]
+   |          ^^^^^^^^^^
+
+error: aborting due to 2 previous errors
+
diff --git a/src/test/ui/deduplicate-diagnostics.rs b/src/test/ui/deduplicate-diagnostics.rs
new file mode 100644
index 00000000000..4a1f503d757
--- /dev/null
+++ b/src/test/ui/deduplicate-diagnostics.rs
@@ -0,0 +1,8 @@
+// revisions: duplicate deduplicate
+//[duplicate] compile-flags: -Z deduplicate-diagnostics=no
+
+#[derive(Unresolved)] //~ ERROR cannot find derive macro `Unresolved` in this scope
+                      //[duplicate]~| ERROR cannot find derive macro `Unresolved` in this scope
+struct S;
+
+fn main() {}
diff --git a/src/test/ui/dollar-crate/dollar-crate-is-keyword.rs b/src/test/ui/dollar-crate/dollar-crate-is-keyword.rs
index 6deaeb81179..d625163dc7e 100644
--- a/src/test/ui/dollar-crate/dollar-crate-is-keyword.rs
+++ b/src/test/ui/dollar-crate/dollar-crate-is-keyword.rs
@@ -6,10 +6,9 @@ macro_rules! m {
             struct $crate {} //~ ERROR expected identifier, found reserved identifier `$crate`
         }
 
-        use $crate; // OK
-                    //~^ WARN `$crate` may not be imported
+        use $crate; //~ ERROR `$crate` may not be imported
         use $crate as $crate; //~ ERROR expected identifier, found reserved identifier `$crate`
-                              //~^ WARN `$crate` may not be imported
+        //~^ ERROR `$crate` may not be imported
     }
 }
 
diff --git a/src/test/ui/dollar-crate/dollar-crate-is-keyword.stderr b/src/test/ui/dollar-crate/dollar-crate-is-keyword.stderr
index 5d4f39086ce..f5a5f13f912 100644
--- a/src/test/ui/dollar-crate/dollar-crate-is-keyword.stderr
+++ b/src/test/ui/dollar-crate/dollar-crate-is-keyword.stderr
@@ -8,7 +8,7 @@ LL | m!();
    | ----- in this macro invocation
 
 error: expected identifier, found reserved identifier `$crate`
-  --> $DIR/dollar-crate-is-keyword.rs:11:23
+  --> $DIR/dollar-crate-is-keyword.rs:10:23
    |
 LL |         use $crate as $crate;
    |                       ^^^^^^ expected identifier, found reserved identifier
@@ -16,27 +16,23 @@ LL |         use $crate as $crate;
 LL | m!();
    | ----- in this macro invocation
 
-warning: `$crate` may not be imported
+error: `$crate` may not be imported
   --> $DIR/dollar-crate-is-keyword.rs:9:9
    |
-LL |         use $crate; // OK
+LL |         use $crate;
    |         ^^^^^^^^^^^
 ...
 LL | m!();
    | ----- in this macro invocation
-   |
-   = note: `use $crate;` was erroneously allowed and will become a hard error in a future release
 
-warning: `$crate` may not be imported
-  --> $DIR/dollar-crate-is-keyword.rs:11:9
+error: `$crate` may not be imported
+  --> $DIR/dollar-crate-is-keyword.rs:10:9
    |
 LL |         use $crate as $crate;
    |         ^^^^^^^^^^^^^^^^^^^^^
 ...
 LL | m!();
    | ----- in this macro invocation
-   |
-   = note: `use $crate;` was erroneously allowed and will become a hard error in a future release
 
-error: aborting due to 2 previous errors
+error: aborting due to 4 previous errors
 
diff --git a/src/test/ui/extern/issue-64655-allow-unwind-when-calling-panic-directly.rs b/src/test/ui/extern/issue-64655-allow-unwind-when-calling-panic-directly.rs
index 8727c9d1ca6..74c6e501c91 100644
--- a/src/test/ui/extern/issue-64655-allow-unwind-when-calling-panic-directly.rs
+++ b/src/test/ui/extern/issue-64655-allow-unwind-when-calling-panic-directly.rs
@@ -22,7 +22,7 @@
 //[thin]compile-flags: -C lto=thin
 //[fat]compile-flags: -C lto=fat
 
-#![feature(core_panic, panic_internals)]
+#![feature(core_panic)]
 
 // (For some reason, reproducing the LTO issue requires pulling in std
 // explicitly this way.)
@@ -50,9 +50,7 @@ fn main() {
         }
 
         let _guard = Droppable;
-        let s = "issue-64655-allow-unwind-when-calling-panic-directly.rs";
-        let location = core::panic::Location::internal_constructor(s, 17, 4);
-        core::panicking::panic("???", &location);
+        core::panicking::panic("???");
     });
 
     let wait = handle.join();
diff --git a/src/test/ui/imports/import-crate-var.rs b/src/test/ui/imports/import-crate-var.rs
index b9d146d3735..aac5a15d3e6 100644
--- a/src/test/ui/imports/import-crate-var.rs
+++ b/src/test/ui/imports/import-crate-var.rs
@@ -1,10 +1,8 @@
-// check-pass
 // aux-build:import_crate_var.rs
 
 #[macro_use] extern crate import_crate_var;
 
 fn main() {
     m!();
-    //~^ WARN `$crate` may not be imported
-    //~| NOTE `use $crate;` was erroneously allowed and will become a hard error
+    //~^ ERROR `$crate` may not be imported
 }
diff --git a/src/test/ui/imports/import-crate-var.stderr b/src/test/ui/imports/import-crate-var.stderr
index 2f8c845156a..85f15ad4648 100644
--- a/src/test/ui/imports/import-crate-var.stderr
+++ b/src/test/ui/imports/import-crate-var.stderr
@@ -1,9 +1,10 @@
-warning: `$crate` may not be imported
-  --> $DIR/import-crate-var.rs:7:5
+error: `$crate` may not be imported
+  --> $DIR/import-crate-var.rs:6:5
    |
 LL |     m!();
    |     ^^^^^
    |
-   = note: `use $crate;` was erroneously allowed and will become a hard error in a future release
-   = note: this warning originates in a macro outside of the current crate (in Nightly builds, run with -Z external-macro-backtrace for more info)
+   = note: this error originates in a macro outside of the current crate (in Nightly builds, run with -Z external-macro-backtrace for more info)
+
+error: aborting due to previous error
 
diff --git a/src/test/ui/rfc-2091-track-caller/caller-location-intrinsic.rs b/src/test/ui/rfc-2091-track-caller/caller-location-intrinsic.rs
index 0a79aea376f..090e912c1d0 100644
--- a/src/test/ui/rfc-2091-track-caller/caller-location-intrinsic.rs
+++ b/src/test/ui/rfc-2091-track-caller/caller-location-intrinsic.rs
@@ -4,16 +4,16 @@
 
 #[inline(never)]
 #[track_caller]
-fn defeat_const_prop() -> &'static core::panic::Location<'static> {
+fn codegen_caller_loc() -> &'static core::panic::Location<'static> {
     core::panic::Location::caller()
 }
 
 macro_rules! caller_location_from_macro {
-    () => (defeat_const_prop());
+    () => (codegen_caller_loc());
 }
 
 fn main() {
-    let loc = defeat_const_prop();
+    let loc = codegen_caller_loc();
     assert_eq!(loc.file(), file!());
     assert_eq!(loc.line(), 16);
     assert_eq!(loc.column(), 15);
diff --git a/src/test/ui/rfc-2091-track-caller/diverging-caller-location.rs b/src/test/ui/rfc-2091-track-caller/diverging-caller-location.rs
new file mode 100644
index 00000000000..1fb75ef35ff
--- /dev/null
+++ b/src/test/ui/rfc-2091-track-caller/diverging-caller-location.rs
@@ -0,0 +1,19 @@
+// run-fail
+
+//! This test ensures that `#[track_caller]` can be applied directly to diverging functions, as
+//! the tracking issue says: https://github.com/rust-lang/rust/issues/47809#issue-292138490.
+//! Because the annotated function must diverge and a panic keeps that faster than an infinite loop,
+//! we don't inspect the location returned -- it would be difficult to distinguish between the
+//! explicit panic and a failed assertion. That it compiles and runs is enough for this one.
+
+#![feature(track_caller)]
+
+#[track_caller]
+fn doesnt_return() -> ! {
+    let _location = core::panic::Location::caller();
+    panic!("huzzah");
+}
+
+fn main() {
+    doesnt_return();
+}
diff --git a/src/test/ui/rfc-2091-track-caller/track-caller-attribute.rs b/src/test/ui/rfc-2091-track-caller/track-caller-attribute.rs
index 8436ee510a5..76a380ed3e3 100644
--- a/src/test/ui/rfc-2091-track-caller/track-caller-attribute.rs
+++ b/src/test/ui/rfc-2091-track-caller/track-caller-attribute.rs
@@ -1,6 +1,6 @@
 // run-pass
 
-#![feature(const_fn, track_caller)]
+#![feature(track_caller)]
 
 use std::panic::Location;