4 files changed, 155 insertions, 6 deletions
diff --git a/tests/rustdoc/inline_cross/auxiliary/default-generic-args.rs b/tests/rustdoc/inline_cross/auxiliary/default-generic-args.rs
new file mode 100644
index 00000000000..1e31f18927e
--- /dev/null
+++ b/tests/rustdoc/inline_cross/auxiliary/default-generic-args.rs
@@ -0,0 +1,45 @@
+pub type BoxedStr = Box<str>;
+pub type IntMap = std::collections::HashMap<i64, u64>;
+
+pub struct TyPair<T, U = T>(T, U);
+
+pub type T0 = TyPair<i32>;
+pub type T1 = TyPair<i32, u32>;
+pub type T2<K> = TyPair<i32, K>;
+pub type T3<Q> = TyPair<Q, Q>;
+
+pub struct CtPair<const C: u32, const D: u32 = C>;
+
+pub type C0 = CtPair<43, 43>;
+pub type C1 = CtPair<0, 1>;
+pub type C2 = CtPair<{1 + 2}, 3>;
+
+pub struct Re<'a, U = &'a ()>(&'a (), U);
+
+pub type R0<'q> = Re<'q>;
+pub type R1<'q> = Re<'q, &'q ()>;
+pub type R2<'q> = Re<'q, &'static ()>;
+pub type H0 = fn(for<'a> fn(Re<'a>));
+pub type H1 = for<'b> fn(for<'a> fn(Re<'a, &'b ()>));
+pub type H2 = for<'a> fn(for<'b> fn(Re<'a, &'b ()>));
+
+pub struct Proj<T: Basis, U = <T as Basis>::Assoc>(T, U);
+pub trait Basis { type Assoc; }
+impl Basis for () { type Assoc = bool; }
+
+pub type P0 = Proj<()>;
+pub type P1 = Proj<(), bool>;
+pub type P2 = Proj<(), ()>;
+
+pub struct Alpha<T = for<'any> fn(&'any ())>(T);
+
+pub type A0 = Alpha;
+pub type A1 = Alpha<for<'arbitrary> fn(&'arbitrary ())>;
+
+pub struct Multi<A = u64, B = u64>(A, B);
+
+pub type M0 = Multi<u64, ()>;
+
+pub trait Trait<'a, T = &'a ()> {}
+
+pub type F = dyn for<'a> Trait<'a>;
diff --git a/tests/rustdoc/inline_cross/default-generic-args.rs b/tests/rustdoc/inline_cross/default-generic-args.rs
new file mode 100644
index 00000000000..c9a87a19901
--- /dev/null
+++ b/tests/rustdoc/inline_cross/default-generic-args.rs
@@ -0,0 +1,104 @@
+#![crate_name = "user"]
+// aux-crate:default_generic_args=default-generic-args.rs
+// edition:2021
+
+// @has user/type.BoxedStr.html
+// @has - '//*[@class="rust item-decl"]//code' "Box<str>"
+pub use default_generic_args::BoxedStr;
+
+// @has user/type.IntMap.html
+// @has - '//*[@class="rust item-decl"]//code' "HashMap<i64, u64>"
+pub use default_generic_args::IntMap;
+
+// @has user/type.T0.html
+// @has - '//*[@class="rust item-decl"]//code' "TyPair<i32>"
+pub use default_generic_args::T0;
+
+// @has user/type.T1.html
+// @has - '//*[@class="rust item-decl"]//code' "TyPair<i32, u32>"
+pub use default_generic_args::T1;
+
+// @has user/type.T2.html
+// @has - '//*[@class="rust item-decl"]//code' "TyPair<i32, K>"
+pub use default_generic_args::T2;
+
+// @has user/type.T3.html
+// @has - '//*[@class="rust item-decl"]//code' "TyPair<Q>"
+pub use default_generic_args::T3;
+
+// @has user/type.C0.html
+// @has - '//*[@class="rust item-decl"]//code' "CtPair<43>"
+pub use default_generic_args::C0;
+
+// @has user/type.C1.html
+// @has - '//*[@class="rust item-decl"]//code' "CtPair<0, 1>"
+pub use default_generic_args::C1;
+
+// @has user/type.C2.html
+// @has - '//*[@class="rust item-decl"]//code' "CtPair<default_generic_args::::C2::{constant#0}, 3>"
+pub use default_generic_args::C2;
+
+// @has user/type.R0.html
+// @has - '//*[@class="rust item-decl"]//code' "Re<'q>"
+pub use default_generic_args::R0;
+
+// @has user/type.R1.html
+// @has - '//*[@class="rust item-decl"]//code' "Re<'q>"
+pub use default_generic_args::R1;
+
+// @has user/type.R2.html
+// Check that we consider regions:
+// @has - '//*[@class="rust item-decl"]//code' "Re<'q, &'static ()>"
+pub use default_generic_args::R2;
+
+// @has user/type.H0.html
+// Check that we handle higher-ranked regions correctly:
+// @has - '//*[@class="rust item-decl"]//code' "fn(_: for<'a> fn(_: Re<'a>))"
+pub use default_generic_args::H0;
+
+// @has user/type.H1.html
+// Check that we don't conflate distinct universially quantified regions (#1):
+// @has - '//*[@class="rust item-decl"]//code' "for<'b> fn(_: for<'a> fn(_: Re<'a, &'b ()>))"
+pub use default_generic_args::H1;
+
+// @has user/type.H2.html
+// Check that we don't conflate distinct universially quantified regions (#2):
+// @has - '//*[@class="rust item-decl"]//code' "for<'a> fn(_: for<'b> fn(_: Re<'a, &'b ()>))"
+pub use default_generic_args::H2;
+
+// @has user/type.P0.html
+// @has - '//*[@class="rust item-decl"]//code' "Proj<()>"
+pub use default_generic_args::P0;
+
+// @has user/type.P1.html
+// @has - '//*[@class="rust item-decl"]//code' "Proj<(), bool>"
+pub use default_generic_args::P1;
+
+// @has user/type.P2.html
+// @has - '//*[@class="rust item-decl"]//code' "Proj<(), ()>"
+pub use default_generic_args::P2;
+
+// @has user/type.A0.html
+// Ensure that we elide generic arguments that are alpha-equivalent to their respective
+// generic parameter (modulo substs) (#1):
+// @has - '//*[@class="rust item-decl"]//code' "Alpha"
+pub use default_generic_args::A0;
+
+// @has user/type.A1.html
+// Ensure that we elide generic arguments that are alpha-equivalent to their respective
+// generic parameter (modulo substs) (#1):
+// @has - '//*[@class="rust item-decl"]//code' "Alpha"
+pub use default_generic_args::A1;
+
+// @has user/type.M0.html
+// Test that we don't elide `u64` even if it coincides with `A`'s default precisely because
+// `()` is not the default of `B`. Mindlessly eliding `u64` would lead to `M<()>` which is a
+// different type (`M<(), u64>` versus `M<u64, ()>`).
+// @has - '//*[@class="rust item-decl"]//code' "Multi<u64, ()>"
+pub use default_generic_args::M0;
+
+// @has user/type.F.html
+// FIXME: Ideally, we would elide `&'a ()` but `'a` is an escaping bound var which we can't reason
+//        about at the moment since we don't keep track of bound vars.
+// @has - '//*[@class="rust item-decl"]//code' "dyn for<'a> Trait<'a, &'a ()>"
+pub use default_generic_args::F;
diff --git a/tests/rustdoc/inline_cross/dyn_trait.rs b/tests/rustdoc/inline_cross/dyn_trait.rs
index 679972f035a..9871be79ca3 100644
--- a/tests/rustdoc/inline_cross/dyn_trait.rs
+++ b/tests/rustdoc/inline_cross/dyn_trait.rs
@@ -75,16 +75,16 @@ pub use dyn_trait::AmbiguousBoundWrappedEarly1;
 pub use dyn_trait::AmbiguousBoundWrappedStatic;
 
 // @has user/type.NoBoundsWrappedDefaulted.html
-// @has - '//*[@class="rust item-decl"]//code' "Box<dyn Trait, Global>;"
+// @has - '//*[@class="rust item-decl"]//code' "Box<dyn Trait>;"
 pub use dyn_trait::NoBoundsWrappedDefaulted;
 // @has user/type.NoBoundsWrappedEarly.html
-// @has - '//*[@class="rust item-decl"]//code' "Box<dyn Trait + 'e, Global>;"
+// @has - '//*[@class="rust item-decl"]//code' "Box<dyn Trait + 'e>;"
 pub use dyn_trait::NoBoundsWrappedEarly;
 // @has user/fn.nbwl.html
-// @has - '//pre[@class="rust item-decl"]' "nbwl<'l>(_: Box<dyn Trait + 'l, Global>)"
+// @has - '//pre[@class="rust item-decl"]' "nbwl<'l>(_: Box<dyn Trait + 'l>)"
 pub use dyn_trait::no_bounds_wrapped_late as nbwl;
 // @has user/fn.nbwel.html
-// @has - '//pre[@class="rust item-decl"]' "nbwel(_: Box<dyn Trait + '_, Global>)"
+// @has - '//pre[@class="rust item-decl"]' "nbwel(_: Box<dyn Trait + '_>)"
 // NB: It might seem counterintuitive to display the explicitly elided lifetime `'_` here instead of
 // eliding it but this behavior is correct: The default is `'static` here which != `'_`.
 pub use dyn_trait::no_bounds_wrapped_elided as nbwel;
diff --git a/tests/rustdoc/inline_cross/impl_trait.rs b/tests/rustdoc/inline_cross/impl_trait.rs
index 9b22026e490..3a2f5d16004 100644
--- a/tests/rustdoc/inline_cross/impl_trait.rs
+++ b/tests/rustdoc/inline_cross/impl_trait.rs
@@ -4,7 +4,7 @@
 extern crate impl_trait_aux;
 
 // @has impl_trait/fn.func.html
-// @has - '//pre[@class="rust item-decl"]' "pub fn func<'a>(_x: impl Clone + Into<Vec<u8, Global>> + 'a)"
+// @has - '//pre[@class="rust item-decl"]' "pub fn func<'a>(_x: impl Clone + Into<Vec<u8>> + 'a)"
 // @!has - '//pre[@class="rust item-decl"]' 'where'
 pub use impl_trait_aux::func;
 
@@ -34,6 +34,6 @@ pub use impl_trait_aux::func4;
 pub use impl_trait_aux::func5;
 
 // @has impl_trait/struct.Foo.html
-// @has - '//*[@id="method.method"]//h4[@class="code-header"]' "pub fn method<'a>(_x: impl Clone + Into<Vec<u8, Global>> + 'a)"
+// @has - '//*[@id="method.method"]//h4[@class="code-header"]' "pub fn method<'a>(_x: impl Clone + Into<Vec<u8>> + 'a)"
 // @!has - '//*[@id="method.method"]//h4[@class="code-header"]' 'where'
 pub use impl_trait_aux::Foo;