Adding upstream version 1.64.0+dfsg1.upstream/1.64.0+dfsg1

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 50 insertions, 0 deletions

diff --git a/compiler/rustc_error_codes/src/error_codes/E0575.md b/compiler/rustc_error_codes/src/error_codes/E0575.md
new file mode 100644
index 000000000..903939a9a
--- /dev/null
+++ b/compiler/rustc_error_codes/src/error_codes/E0575.md
@@ -0,0 +1,50 @@
+Something other than a type or an associated type was given.
+
+Erroneous code example:
+
+```compile_fail,E0575
+enum Rick { Morty }
+
+let _: <u8 as Rick>::Morty; // error!
+
+trait Age {
+    type Empire;
+    fn Mythology() {}
+}
+
+impl Age for u8 {
+    type Empire = u16;
+}
+
+let _: <u8 as Age>::Mythology; // error!
+```
+
+In both cases, we're declaring a variable (called `_`) and we're giving it a
+type. However, `<u8 as Rick>::Morty` and `<u8 as Age>::Mythology` aren't types,
+therefore the compiler throws an error.
+
+`<u8 as Rick>::Morty` is an enum variant, you cannot use a variant as a type,
+you have to use the enum directly:
+
+```
+enum Rick { Morty }
+
+let _: Rick; // ok!
+```
+
+`<u8 as Age>::Mythology` is a trait method, which is definitely not a type.
+However, the `Age` trait provides an associated type `Empire` which can be
+used as a type:
+
+```
+trait Age {
+    type Empire;
+    fn Mythology() {}
+}
+
+impl Age for u8 {
+    type Empire = u16;
+}
+
+let _: <u8 as Age>::Empire; // ok!
+```