rust: make TryFrom macro more resilient

If the enum includes values such as "Ok", "Err", or "Error", the TryInto
macro can cause errors.  Be careful and qualify identifiers with the full
path, or in the case of TryFrom<>::Error do not use the associated type
at all.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

1 files changed, 4 insertions, 3 deletions

diff --git a/rust/qemu-api-macros/src/lib.rs b/rust/qemu-api-macros/src/lib.rs
index 1034707..c18bb4e 100644
--- a/rust/qemu-api-macros/src/lib.rs
+++ b/rust/qemu-api-macros/src/lib.rs
@@ -203,8 +203,8 @@ fn derive_tryinto_body(
     Ok(quote! {
         #(const #discriminants: #repr = #name::#discriminants as #repr;)*;
         match value {
-            #(#discriminants => Ok(#name::#discriminants),)*
-            _ => Err(value),
+            #(#discriminants => core::result::Result::Ok(#name::#discriminants),)*
+            _ => core::result::Result::Err(value),
         }
     })
 }
@@ -236,7 +236,8 @@ fn derive_tryinto_or_error(input: DeriveInput) -> Result<proc_macro2::TokenStrea
         impl core::convert::TryFrom<#repr> for #name {
             type Error = #repr;
 
-            fn try_from(value: #repr) -> Result<Self, Self::Error> {
+            #[allow(ambiguous_associated_items)]
+            fn try_from(value: #repr) -> Result<Self, #repr> {
                 #body
             }
         }