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Reimplement print_region in type_name.rs. #145033

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4 changes: 3 additions & 1 deletion compiler/rustc_const_eval/src/util/type_name.rs
Original file line number Diff line number Diff line change
Expand Up @@ -18,7 +18,9 @@ impl<'tcx> Printer<'tcx> for AbsolutePathPrinter<'tcx> {
}

fn print_region(&mut self, _region: ty::Region<'_>) -> Result<(), PrintError> {
unreachable!(); // because `<Self As PrettyPrinter>::should_print_region` returns false
// This is reachable (via `pretty_print_dyn_existential`) even though
// `<Self As PrettyPrinter>::should_print_region` returns false. See #144994.
Ok(())
}

fn print_type(&mut self, ty: Ty<'tcx>) -> Result<(), PrintError> {
Expand Down
4 changes: 3 additions & 1 deletion compiler/rustc_symbol_mangling/src/legacy.rs
Original file line number Diff line number Diff line change
Expand Up @@ -234,7 +234,9 @@ impl<'tcx> Printer<'tcx> for SymbolPrinter<'tcx> {
}

fn print_region(&mut self, _region: ty::Region<'_>) -> Result<(), PrintError> {
unreachable!(); // because `<Self As PrettyPrinter>::should_print_region` returns false
// This might be reachable (via `pretty_print_dyn_existential`) even though
// `<Self As PrettyPrinter>::should_print_region` returns false. See #144994.
Ok(())
}

fn print_type(&mut self, ty: Ty<'tcx>) -> Result<(), PrintError> {
Expand Down
81 changes: 77 additions & 4 deletions tests/ui/type/type-name-basic.rs
Original file line number Diff line number Diff line change
Expand Up @@ -6,12 +6,85 @@
#![allow(dead_code)]

use std::any::type_name;
use std::borrow::Cow;

struct Foo<T> {
x: T,
struct Foo<T>(T);

struct Bar<'a>(&'a u32);

struct Baz<'a, T>(&'a T);

trait TrL<'a> {}
trait TrLA<'a> {
type A;
}
trait TrLT<'a, T> {}
trait TrLTA<'a, T> {
type A;
}

macro_rules! t {
($ty:ty, $str:literal) => {
assert_eq!(type_name::<$ty>(), $str);
}
}

pub fn main() {
assert_eq!(type_name::<isize>(), "isize");
assert_eq!(type_name::<Foo<usize>>(), "type_name_basic::Foo<usize>");
t!(bool, "bool");
t!(char, "char");

t!(u8, "u8");
t!(u16, "u16");
t!(u32, "u32");
t!(u64, "u64");
t!(u128, "u128");
t!(usize, "usize");

t!(i8, "i8");
t!(i16, "i16");
t!(i32, "i32");
t!(i64, "i64");
t!(i128, "i128");
t!(isize, "isize");

t!(String, "alloc::string::String");
t!(str, "str");
t!(&str, "&str");
t!(&'static str, "&str");

t!((u16, u32, u64), "(u16, u32, u64)");
t!([usize; 4], "[usize; 4]");
t!([usize], "[usize]");
t!(&[usize], "&[usize]");

t!(*const bool, "*const bool");
t!(*mut u64, "*mut u64");

t!(Vec<Vec<u32>>, "alloc::vec::Vec<alloc::vec::Vec<u32>>");
t!(Foo<usize>, "type_name_basic::Foo<usize>");
t!(Bar<'static>, "type_name_basic::Bar");
t!(Baz<'static, u32>, "type_name_basic::Baz<u32>");

// FIXME: lifetime omission means these all print badly.
t!(dyn TrL<'static>, "dyn type_name_basic::TrL<>");
t!(dyn TrLA<'static, A = u32>, "dyn type_name_basic::TrLA<, A = u32>");
t!(
dyn TrLT<'static, Cow<'static, ()>>,
"dyn type_name_basic::TrLT<, alloc::borrow::Cow<()>>"
);
t!(
dyn TrLTA<'static, u32, A = Cow<'static, ()>>,
"dyn type_name_basic::TrLTA<, u32, A = alloc::borrow::Cow<()>>"
);

t!(fn(i32) -> i32, "fn(i32) -> i32");
t!(dyn for<'a> Fn(&'a u32), "dyn core::ops::function::Fn(&u32)");

struct S<'a, T>(&'a T);
impl<'a, T: Clone> S<'a, T> {
fn test() {
t!(Cow<'a, T>, "alloc::borrow::Cow<u32>");
}
}
S::<u32>::test();
}
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