Require Rust 1.75+ for RPITIT (return position impl trait in trait)

Author: dtolnay

.github/workflows/ci.yml

@@ -24,7 +24,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        rust: [nightly, beta, stable, 1.70.0, 1.56.0]
+        rust: [nightly, beta, stable, 1.75.0, 1.70.0, 1.56.0]
     timeout-minutes: 45
     steps:
       - uses: actions/checkout@v4

tests/test.rs

@@ -1663,6 +1663,7 @@ pub mod issue277 {
 }
 
 // https://github.com/dtolnay/async-trait/issues/281
+#[rustversion::since(1.75)]
 pub mod issue281 {
     use async_trait::async_trait;