Adopt let else in more places

compiler/rustc_codegen_ssa/src/back/link.rs

@@ -674,9 +674,8 @@ fn link_natively<'a, B: ArchiveBuilder<'a>>(
     loop {
         i += 1;
         prog = sess.time("run_linker", || exec_linker(sess, &cmd, out_filename, tmpdir));
-        let output = match prog {
-            Ok(ref output) => output,
-            Err(_) => break,
+        let Ok(ref output) = prog else {
+            break;
         };
         if output.status.success() {
             break;
@@ -2025,9 +2024,8 @@ fn add_local_native_libraries(
     let search_path = OnceCell::new();
     let mut last = (NativeLibKind::Unspecified, None);
     for lib in relevant_libs {
-        let name = match lib.name {
-            Some(l) => l,
-            None => continue,
+        let Some(name) = lib.name else {
+            continue;
         };
 
         // Skip if this library is the same as the last.
@@ -2382,9 +2380,8 @@ fn add_upstream_native_libraries(
     let mut last = (NativeLibKind::Unspecified, None);
     for &cnum in &codegen_results.crate_info.used_crates {
         for lib in codegen_results.crate_info.native_libraries[&cnum].iter() {
-            let name = match lib.name {
-                Some(l) => l,
-                None => continue,
+            let Some(name) = lib.name else {
+                continue;
             };
             if !relevant_lib(sess, &lib) {
                 continue;

compiler/rustc_codegen_ssa/src/back/metadata.rs

@@ -79,15 +79,14 @@ fn search_for_metadata<'a>(
     bytes: &'a [u8],
     section: &str,
 ) -> Result<&'a [u8], String> {
-    let file = match object::File::parse(bytes) {
-        Ok(f) => f,
+    let Ok(file) = object::File::parse(bytes) else {
         // The parse above could fail for odd reasons like corruption, but for
         // now we just interpret it as this target doesn't support metadata
         // emission in object files so the entire byte slice itself is probably
         // a metadata file. Ideally though if necessary we could at least check
         // the prefix of bytes to see if it's an actual metadata object and if
         // not forward the error along here.
-        Err(_) => return Ok(bytes),
+        return Ok(bytes);
     };
     file.section_by_name(section)
         .ok_or_else(|| format!("no `{}` section in '{}'", section, path.display()))?

compiler/rustc_codegen_ssa/src/back/symbol_export.rs

@@ -448,10 +448,7 @@ fn wasm_import_module_map(tcx: TyCtxt<'_>, cnum: CrateNum) -> FxHashMap<DefId, S
     let mut ret = FxHashMap::default();
     for (def_id, lib) in tcx.foreign_modules(cnum).iter() {
         let module = def_id_to_native_lib.get(&def_id).and_then(|s| s.wasm_import_module);
-        let module = match module {
-            Some(s) => s,
-            None => continue,
-        };
+        let Some(module) = module else { continue };
         ret.extend(lib.foreign_items.iter().map(|id| {
             assert_eq!(id.krate, cnum);
             (*id, module.to_string())