Fix MSRV compilation (#3927)

Author: daxpedda

CHANGELOG.md

@@ -33,6 +33,9 @@
 * Fix `catch` not being thread-safe.
   [#3879](https://github.com/rustwasm/wasm-bindgen/pull/3879)
 
+* Fix MSRV compilation.
+  [#3927](https://github.com/rustwasm/wasm-bindgen/pull/3927)
+
 --------------------------------------------------------------------------------
 
 ## [0.2.92](https://github.com/rustwasm/wasm-bindgen/compare/0.2.91...0.2.92)

crates/backend/src/codegen.rs

@@ -1716,9 +1716,9 @@ fn splat(
     let mut args = Vec::new();
     let mut names = Vec::new();
 
-    for n in 1..=4 {
-        let arg_name = format_ident!("{name}_{n}");
-        let prim_name = format_ident!("Prim{n}");
+    for n in 1_u32..=4 {
+        let arg_name = format_ident!("{}_{}", name, n);
+        let prim_name = format_ident!("Prim{}", n);
         args.push(quote! {
             #arg_name: <#abi as #wasm_bindgen::convert::WasmAbi>::#prim_name
         });

src/lib.rs

@@ -1820,7 +1820,7 @@ pub mod __rt {
         }
     }
 
-    pub const fn flat_len<const SIZE: usize, T>(slices: [&[T]; SIZE]) -> usize {
+    pub const fn flat_len<T, const SIZE: usize>(slices: [&[T]; SIZE]) -> usize {
         let mut len = 0;
         let mut i = 0;
         while i < slices.len() {