Stabilize the type_name intrinsic in core::any

Closes rust-lang/rfcs#1428

Author: sfackler

src/libcore/any.rs

@@ -450,3 +450,29 @@ impl TypeId {
         }
     }
 }
+
+/// Returns the name of a type as a string slice.
+///
+/// # Note
+///
+/// This is intended for diagnostic use. The exact contents and format of the
+/// string are not specified, other than being a best-effort description of the
+/// type. For example, `type_name::<Option<String>>()` could return the
+/// `"Option<String>"` or `"std::option::Option<std::string::String>"`, but not
+/// `"foobar"`. In addition, the output may change between versions of the
+/// compiler.
+///
+/// The type name should not be considered a unique identifier of a type;
+/// multiple types may share the same type name.
+///
+/// The current implementation uses the same infrastructure as compiler
+/// diagnostics and debuginfo, but this is not guaranteed.
+#[stable(feature = "type_name", since = "1.38.0")]
+pub fn type_name<T: ?Sized>() -> &'static str {
+    #[cfg(bootstrap)]
+    unsafe {
+        intrinsics::type_name::<T>()
+    }
+    #[cfg(not(bootstrap))]
+    intrinsics::type_name::<T>()
+}

src/librustc/traits/query/normalize.rs

@@ -34,7 +34,7 @@ impl<'cx, 'tcx> At<'cx, 'tcx> {
     {
         debug!(
             "normalize::<{}>(value={:?}, param_env={:?})",
-            unsafe { ::std::intrinsics::type_name::<T>() },
+            ::std::any::type_name::<T>(),
             value,
             self.param_env,
         );

src/librustc/traits/query/normalize_erasing_regions.rs

@@ -22,7 +22,7 @@ impl<'tcx> TyCtxt<'tcx> {
     {
         debug!(
             "normalize_erasing_regions::<{}>(value={:?}, param_env={:?})",
-            unsafe { ::std::intrinsics::type_name::<T>() },
+            ::std::any::type_name::<T>(),
             value,
             param_env,
         );

src/librustc/ty/query/config.rs

@@ -69,7 +69,7 @@ impl<'tcx, M: QueryAccessors<'tcx, Key = DefId>> QueryDescription<'tcx> for M {
         if !tcx.sess.verbose() {
             format!("processing `{}`", tcx.def_path_str(def_id)).into()
         } else {
-            let name = unsafe { ::std::intrinsics::type_name::<M>() };
+            let name = ::std::any::type_name::<M>();
             format!("processing {:?} with query `{}`", def_id, name).into()
         }
     }

src/librustc/ty/query/mod.rs

@@ -54,7 +54,7 @@ use rustc_target::spec::PanicStrategy;
 use std::borrow::Cow;
 use std::ops::Deref;
 use std::sync::Arc;
-use std::intrinsics::type_name;
+use std::any::type_name;
 use syntax_pos::{Span, DUMMY_SP};
 use syntax_pos::symbol::InternedString;
 use syntax::attr;

src/librustc/ty/query/on_disk_cache.rs

@@ -1060,7 +1060,7 @@ where
     Q::Value: Encodable,
 {
     let desc = &format!("encode_query_results for {}",
-        unsafe { ::std::intrinsics::type_name::<Q>() });
+        ::std::any::type_name::<Q>());
 
     time_ext(tcx.sess.time_extended(), Some(tcx.sess), desc, || {
         let map = Q::query_cache(tcx).borrow();

src/librustc/ty/query/plumbing.rs

@@ -782,9 +782,9 @@ macro_rules! define_queries_inner {
                         #[cfg(not(debug_assertions))]
                         cache_hits: 0,
                         key_size: mem::size_of::<Q::Key>(),
-                        key_type: unsafe { type_name::<Q::Key>() },
+                        key_type: type_name::<Q::Key>(),
                         value_size: mem::size_of::<Q::Value>(),
-                        value_type: unsafe { type_name::<Q::Value>() },
+                        value_type: type_name::<Q::Value>(),
                         entry_count: map.results.len(),
                     }
                 }

src/librustc_mir/transform/mod.rs

@@ -127,7 +127,7 @@ impl<'tcx> MirSource<'tcx> {
 /// Generates a default name for the pass based on the name of the
 /// type `T`.
 pub fn default_name<T: ?Sized>() -> Cow<'static, str> {
-    let name = unsafe { ::std::intrinsics::type_name::<T>() };
+    let name = ::std::any::type_name::<T>();
     if let Some(tail) = name.rfind(":") {
         Cow::from(&name[tail+1..])
     } else {

src/librustc_typeck/check/intrinsic.rs

@@ -71,7 +71,7 @@ pub fn intrisic_operation_unsafety(intrinsic: &str) -> hir::Unsafety {
         "saturating_add" | "saturating_sub" |
         "rotate_left" | "rotate_right" |
         "ctpop" | "ctlz" | "cttz" | "bswap" | "bitreverse" |
-        "minnumf32" | "minnumf64" | "maxnumf32" | "maxnumf64"
+        "minnumf32" | "minnumf64" | "maxnumf32" | "maxnumf64" | "type_name"
         => hir::Unsafety::Normal,
         _ => hir::Unsafety::Unsafe,
     }

src/libserialize/serialize.rs

@@ -4,8 +4,8 @@
 Core encoding and decoding interfaces.
 */
 
+use std::any;
 use std::borrow::Cow;
-use std::intrinsics;
 use std::marker::PhantomData;
 use std::path;
 use std::rc::Rc;
@@ -849,9 +849,9 @@ pub trait SpecializationError {
 impl<E> SpecializationError for E {
     default fn not_found<S, T: ?Sized>(trait_name: &'static str, method_name: &'static str) -> E {
         panic!("missing specialization: `<{} as {}<{}>>::{}` not overridden",
-               unsafe { intrinsics::type_name::<S>() },
+               any::type_name::<S>(),
                trait_name,
-               unsafe { intrinsics::type_name::<T>() },
+               any::type_name::<T>(),
                method_name);
     }
 }

src/test/run-pass/consts/const-fn-type-name.rs

@@ -5,7 +5,7 @@
 #![allow(dead_code)]
 
 const fn type_name_wrapper<T>(_: &T) -> &'static str {
-    unsafe { core::intrinsics::type_name::<T>() }
+    core::intrinsics::type_name::<T>()
 }
 
 struct Struct<TA, TB, TC> {

src/test/run-pass/issues/issue-21058.rs

@@ -1,6 +1,5 @@
 // run-pass
 #![allow(dead_code)]
-#![feature(core_intrinsics)]
 
 use std::fmt::Debug;
 
@@ -12,7 +11,7 @@ macro_rules! check {
         assert_eq!(type_name_of_val($ty_of), $expected);
     };
     ($ty:ty, $expected:expr) => {
-        assert_eq!(unsafe { std::intrinsics::type_name::<$ty>()}, $expected);
+        assert_eq!(std::any::type_name::<$ty>(), $expected);
     };
 }
 
@@ -50,7 +49,7 @@ fn bar<T: Trait>() {
 }
 
 fn type_name_of_val<T>(_: T) -> &'static str {
-    unsafe { std::intrinsics::type_name::<T>() }
+    std::any::type_name::<T>()
 }
 
 #[derive(Debug)]

src/test/run-pass/issues/issue-61894.rs

@@ -1,14 +1,14 @@
 #![feature(core_intrinsics)]
 
-use std::intrinsics::type_name;
+use std::any::type_name;
 
 struct Bar<M>(M);
 
 impl<M> Bar<M> {
     fn foo(&self) -> &'static str {
         fn f() {}
         fn type_name_of<T>(_: T) -> &'static str {
-            unsafe { type_name::<T>() }
+            type_name::<T>()
         }
         type_name_of(f)
     }

src/test/run-pass/tydesc-name.rs

@@ -1,16 +1,12 @@
 #![allow(dead_code)]
 
-#![feature(core_intrinsics)]
-
-use std::intrinsics::type_name;
+use std::any::type_name;
 
 struct Foo<T> {
     x: T
 }
 
 pub fn main() {
-    unsafe {
-        assert_eq!(type_name::<isize>(), "isize");
-        assert_eq!(type_name::<Foo<usize>>(), "tydesc_name::Foo<usize>");
-    }
+    assert_eq!(type_name::<isize>(), "isize");
+    assert_eq!(type_name::<Foo<usize>>(), "tydesc_name::Foo<usize>");
 }