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, 16 insertions, 0 deletions

diff --git a/compiler/rustc_error_codes/src/error_codes/E0596.md b/compiler/rustc_error_codes/src/error_codes/E0596.md
new file mode 100644
index 000000000..95669309b
--- /dev/null
+++ b/compiler/rustc_error_codes/src/error_codes/E0596.md
@@ -0,0 +1,16 @@
+This error occurs because you tried to mutably borrow a non-mutable variable.
+
+Erroneous code example:
+
+```compile_fail,E0596
+let x = 1;
+let y = &mut x; // error: cannot borrow mutably
+```
+
+In here, `x` isn't mutable, so when we try to mutably borrow it in `y`, it
+fails. To fix this error, you need to make `x` mutable:
+
+```
+let mut x = 1;
+let y = &mut x; // ok!
+```