Auto merge of #76195 - lcnr:const-Self, r=varkor

allow concrete self types in consts

This is quite a bad hack to fix #75486. There might be a better way to check if the self type depends on generic parameters, but I wasn't able to come up with one.

r? `@varkor` cc `@petrochenkov`

7 files changed, 93 insertions, 5 deletions

diff --git a/src/librustdoc/clean/utils.rs b/src/librustdoc/clean/utils.rs
index c577b771d60..58b76d24a5b 100644
--- a/src/librustdoc/clean/utils.rs
+++ b/src/librustdoc/clean/utils.rs
@@ -601,7 +601,7 @@ pub fn register_res(cx: &DocContext<'_>, res: Res) -> DefId {
         },
         Res::Def(DefKind::TraitAlias, i) => (i, TypeKind::TraitAlias),
         Res::SelfTy(Some(def_id), _) => (def_id, TypeKind::Trait),
-        Res::SelfTy(_, Some(impl_def_id)) => return impl_def_id,
+        Res::SelfTy(_, Some((impl_def_id, _))) => return impl_def_id,
         _ => return res.def_id(),
     };
     if did.is_local() {
diff --git a/src/test/ui/const-generics/issues/issue-62504.min.stderr b/src/test/ui/const-generics/issues/issue-62504.min.stderr
index 752df17aad6..8f794312834 100644
--- a/src/test/ui/const-generics/issues/issue-62504.min.stderr
+++ b/src/test/ui/const-generics/issues/issue-62504.min.stderr
@@ -1,10 +1,14 @@
-error: generic parameters must not be used inside of non trivial constant values
+error: generic `Self` types are currently not permitted in anonymous constants
   --> $DIR/issue-62504.rs:19:25
    |
 LL |         ArrayHolder([0; Self::SIZE])
-   |                         ^^^^^^^^^^ non-trivial anonymous constants must not depend on the parameter `Self`
+   |                         ^^^^^^^^^^
    |
-   = help: it is currently only allowed to use either `Self` or `{ Self }` as generic constants
+note: not a concrete type
+  --> $DIR/issue-62504.rs:17:22
+   |
+LL | impl<const X: usize> ArrayHolder<X> {
+   |                      ^^^^^^^^^^^^^^
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/const-generics/issues/issue-62504.rs b/src/test/ui/const-generics/issues/issue-62504.rs
index b520dbe4e80..015f170f00d 100644
--- a/src/test/ui/const-generics/issues/issue-62504.rs
+++ b/src/test/ui/const-generics/issues/issue-62504.rs
@@ -18,7 +18,7 @@ impl<const X: usize> ArrayHolder<X> {
     pub const fn new() -> Self {
         ArrayHolder([0; Self::SIZE])
         //[full]~^ ERROR constant expression depends on a generic parameter
-        //[min]~^^ ERROR generic parameters must not be used inside of non trivial constant values
+        //[min]~^^ ERROR generic `Self` types are currently
     }
 }
 
diff --git a/src/test/ui/const-generics/min_const_generics/self-ty-in-const-1.rs b/src/test/ui/const-generics/min_const_generics/self-ty-in-const-1.rs
new file mode 100644
index 00000000000..0973b373c12
--- /dev/null
+++ b/src/test/ui/const-generics/min_const_generics/self-ty-in-const-1.rs
@@ -0,0 +1,27 @@
+#![feature(min_const_generics)]
+
+trait Foo {
+    fn t1() -> [u8; std::mem::size_of::<Self>()]; //~ERROR generic parameters
+}
+
+struct Bar<T>(T);
+
+impl Bar<u8> {
+    fn t2() -> [u8; std::mem::size_of::<Self>()] { todo!() } // ok
+}
+
+impl<T> Bar<T> {
+    fn t3() -> [u8; std::mem::size_of::<Self>()] {} //~ERROR generic `Self`
+}
+
+trait Baz {
+    fn hey();
+}
+
+impl Baz for u16 {
+    fn hey() {
+        let _: [u8; std::mem::size_of::<Self>()]; // ok
+    }
+}
+
+fn main() {}
diff --git a/src/test/ui/const-generics/min_const_generics/self-ty-in-const-1.stderr b/src/test/ui/const-generics/min_const_generics/self-ty-in-const-1.stderr
new file mode 100644
index 00000000000..89ce58564e4
--- /dev/null
+++ b/src/test/ui/const-generics/min_const_generics/self-ty-in-const-1.stderr
@@ -0,0 +1,22 @@
+error: generic parameters must not be used inside of non trivial constant values
+  --> $DIR/self-ty-in-const-1.rs:4:41
+   |
+LL |     fn t1() -> [u8; std::mem::size_of::<Self>()];
+   |                                         ^^^^ non-trivial anonymous constants must not depend on the parameter `Self`
+   |
+   = help: it is currently only allowed to use either `Self` or `{ Self }` as generic constants
+
+error: generic `Self` types are currently not permitted in anonymous constants
+  --> $DIR/self-ty-in-const-1.rs:14:41
+   |
+LL |     fn t3() -> [u8; std::mem::size_of::<Self>()] {}
+   |                                         ^^^^
+   |
+note: not a concrete type
+  --> $DIR/self-ty-in-const-1.rs:13:9
+   |
+LL | impl<T> Bar<T> {
+   |         ^^^^^^
+
+error: aborting due to 2 previous errors
+
diff --git a/src/test/ui/const-generics/min_const_generics/self-ty-in-const-2.rs b/src/test/ui/const-generics/min_const_generics/self-ty-in-const-2.rs
new file mode 100644
index 00000000000..e7f80d50082
--- /dev/null
+++ b/src/test/ui/const-generics/min_const_generics/self-ty-in-const-2.rs
@@ -0,0 +1,21 @@
+#![feature(min_const_generics)]
+
+struct Bar<T>(T);
+
+trait Baz {
+    fn hey();
+}
+
+impl Baz for u16 {
+    fn hey() {
+        let _: [u8; std::mem::size_of::<Self>()]; // ok
+    }
+}
+
+impl<T> Baz for Bar<T> {
+    fn hey() {
+        let _: [u8; std::mem::size_of::<Self>()]; //~ERROR generic `Self`
+    }
+}
+
+fn main() {}
diff --git a/src/test/ui/const-generics/min_const_generics/self-ty-in-const-2.stderr b/src/test/ui/const-generics/min_const_generics/self-ty-in-const-2.stderr
new file mode 100644
index 00000000000..9ac6410a290
--- /dev/null
+++ b/src/test/ui/const-generics/min_const_generics/self-ty-in-const-2.stderr
@@ -0,0 +1,14 @@
+error: generic `Self` types are currently not permitted in anonymous constants
+  --> $DIR/self-ty-in-const-2.rs:17:41
+   |
+LL |         let _: [u8; std::mem::size_of::<Self>()];
+   |                                         ^^^^
+   |
+note: not a concrete type
+  --> $DIR/self-ty-in-const-2.rs:15:17
+   |
+LL | impl<T> Baz for Bar<T> {
+   |                 ^^^^^^
+
+error: aborting due to previous error
+