Rollup merge of #65664 - anp:panic-location, r=eddyb

`std::panic::Location` is a lang_item, add `core::intrinsics::caller_location` (RFC 2091 3/N)

[Tracking issue](https://github.com/rust-lang/rust/issues/47809)
[RFC text](https://github.com/rust-lang/rfcs/blob/master/text/2091-inline-semantic.md)

@eddyb suggested doing this intrinsic implementation ahead of actually implementing the `#[track_caller]` attribute so that there's an easily tested intermediate step between adding the shim and wiring up the attribute.

1 files changed, 12 insertions, 6 deletions

diff --git a/src/libcore/panic.rs b/src/libcore/panic.rs
index 989fc96732a..51bbf3a8fd2 100644
--- a/src/libcore/panic.rs
+++ b/src/libcore/panic.rs
@@ -35,7 +35,7 @@ use crate::fmt;
 pub struct PanicInfo<'a> {
     payload: &'a (dyn Any + Send),
     message: Option<&'a fmt::Arguments<'a>>,
-    location: Location<'a>,
+    location: &'a Location<'a>,
 }
 
 impl<'a> PanicInfo<'a> {
@@ -45,11 +45,16 @@ impl<'a> PanicInfo<'a> {
                 issue = "0")]
     #[doc(hidden)]
     #[inline]
-    pub fn internal_constructor(message: Option<&'a fmt::Arguments<'a>>,
-                                location: Location<'a>)
-                                -> Self {
+    pub fn internal_constructor(
+        message: Option<&'a fmt::Arguments<'a>>,
+        location: &'a Location<'a>,
+    ) -> Self {
         struct NoPayload;
-        PanicInfo { payload: &NoPayload, location, message }
+        PanicInfo {
+            location,
+            message,
+            payload: &NoPayload,
+        }
     }
 
     #[doc(hidden)]
@@ -162,6 +167,7 @@ impl fmt::Display for PanicInfo<'_> {
 ///
 /// panic!("Normal panic");
 /// ```
+#[cfg_attr(not(bootstrap), lang = "panic_location")]
 #[derive(Debug)]
 #[stable(feature = "panic_hooks", since = "1.10.0")]
 pub struct Location<'a> {
@@ -176,7 +182,7 @@ impl<'a> Location<'a> {
                           and related macros",
                 issue = "0")]
     #[doc(hidden)]
-    pub fn internal_constructor(file: &'a str, line: u32, col: u32) -> Self {
+    pub const fn internal_constructor(file: &'a str, line: u32, col: u32) -> Self {
         Location { file, line, col }
     }