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, 28 insertions, 0 deletions

diff --git a/compiler/rustc_error_codes/src/error_codes/E0478.md b/compiler/rustc_error_codes/src/error_codes/E0478.md
new file mode 100644
index 000000000..4bc5fde2e
--- /dev/null
+++ b/compiler/rustc_error_codes/src/error_codes/E0478.md
@@ -0,0 +1,28 @@
+A lifetime bound was not satisfied.
+
+Erroneous code example:
+
+```compile_fail,E0478
+// Check that the explicit lifetime bound (`'SnowWhite`, in this example) must
+// outlive all the superbounds from the trait (`'kiss`, in this example).
+
+trait Wedding<'t>: 't { }
+
+struct Prince<'kiss, 'SnowWhite> {
+    child: Box<Wedding<'kiss> + 'SnowWhite>,
+    // error: lifetime bound not satisfied
+}
+```
+
+In this example, the `'SnowWhite` lifetime is supposed to outlive the `'kiss`
+lifetime but the declaration of the `Prince` struct doesn't enforce it. To fix
+this issue, you need to specify it:
+
+```
+trait Wedding<'t>: 't { }
+
+struct Prince<'kiss, 'SnowWhite: 'kiss> { // You say here that 'SnowWhite
+                                          // must live longer than 'kiss.
+    child: Box<Wedding<'kiss> + 'SnowWhite>, // And now it's all good!
+}
+```