Truncated error messages with 1.95.0

Code

I tried this code:

use diesel::prelude::*; // diesel = { version = "2.3.7", default-features = false, features = ["with-deprecated"] }

table! {
    users {
        id -> Integer,
    }
}

#[derive(AsChangeset)]
#[diesel(table_name = users)]
struct UserStruct1 {
    #[column_name = "name"]
    full_name: String,
}

#[derive(AsChangeset)]
#[diesel(table_name = users)]
struct UserStruct2 {
    #[column_name]
    id: i32,
}

I expected to see this happen: There is a complete error message containing all wrong instances of wrong attributes in this code snippet.

Example from Rust 1.94.0

warning: #[column_name] attribute form is deprecated                                                                                           
  = help: use `#[diesel(column_name = name)]` instead                                                                                          
                                                                                                                                               
error: unexpected end of input, expected `=`                                                                                                   
       help: the correct format looks like `#[diesel(column_name = foo)]`                                                                      
  --> src/main.rs:19:7                                                                                                                         
   |                                                                                                                                           
19 |     #[column_name]                                                                                                                        
   |       ^^^^^^^^^^^                                                                                                                         
                                                                                                                                               
error[E0425]: cannot find type `name` in module `users`                                                                                        
  --> src/main.rs:12:21                                                                                                                        
   |                                                                                                                                           
12 |     #[column_name = "name"]                                                                                                               
   |                     ^^^^^^ not found in `users`                                                                                           
                                                                                                                                               
error[E0425]: cannot find value `name` in module `users`                                                                                       
  --> src/main.rs:12:21                                                                                                                        
   |                                                                                                                                           
12 |     #[column_name = "name"]                                                                                                               
   |                     ^^^^^^ not found in `users`   

Instead, this happened: Rustc (1.95.0) only emits a truncated error

warning: #[column_name] attribute form is deprecated
  = help: use `#[diesel(column_name = name)]` instead

error: unexpected end of input, expected `=`
       help: the correct format looks like `#[diesel(column_name = foo)]`
  --> src/main.rs:19:7
   |
19 |     #[column_name]
   |       ^^^^^^^^^^^

Version it worked on

It most recently worked on: 1.94.0

Version with regression

rustc --version --verbose:

rustc 1.95.0 (59807616e 2026-04-14)
binary: rustc
commit-hash: 59807616e1fa2540724bfbac14d7976d7e4a3860
commit-date: 2026-04-14
host: x86_64-unknown-linux-gnu
release: 1.95.0
LLVM version: 22.1.2

@rustbot modify labels: +regression-from-stable-to-stable -regression-untriaged

Reproduce the report using the Rust code in src/main.rs with rustc 1.95.0, then compare its diagnostics with rustc 1.94.0. Trace why the later errors are omitted and restore output that includes all wrong attributes and their associated diagnostics; verify both compiler versions' behavior with the example.