Adopt let else in more places

compiler/rustc_codegen_llvm/src/back/archive.rs

@@ -310,10 +310,7 @@ impl<'a> LlvmArchiveBuilder<'a> {
             if let Some(archive) = self.src_archive() {
                 for child in archive.iter() {
                     let child = child.map_err(string_to_io_error)?;
-                    let child_name = match child.name() {
-                        Some(s) => s,
-                        None => continue,
-                    };
+                    let Some(child_name) = child.name() else { continue };
                     if removals.iter().any(|r| r == child_name) {
                         continue;
                     }

compiler/rustc_codegen_llvm/src/back/write.rs

@@ -826,20 +826,14 @@ pub(crate) unsafe fn codegen(
                 let input =
                     unsafe { slice::from_raw_parts(input_ptr as *const u8, input_len as usize) };
 
-                let input = match str::from_utf8(input) {
-                    Ok(s) => s,
-                    Err(_) => return 0,
-                };
+                let Ok(input) = str::from_utf8(input) else { return 0 };
 
                 let output = unsafe {
                     slice::from_raw_parts_mut(output_ptr as *mut u8, output_len as usize)
                 };
                 let mut cursor = io::Cursor::new(output);
 
-                let demangled = match rustc_demangle::try_demangle(input) {
-                    Ok(d) => d,
-                    Err(_) => return 0,
-                };
+                let Ok(demangled) = rustc_demangle::try_demangle(input) else { return 0 };
 
                 if write!(cursor, "{:#}", demangled).is_err() {
                     // Possible only if provided buffer is not big enough

compiler/rustc_codegen_llvm/src/base.rs

@@ -138,10 +138,7 @@ pub fn compile_codegen_unit(tcx: TyCtxt<'_>, cgu_name: Symbol) -> (ModuleCodegen
 }
 
 pub fn set_link_section(llval: &Value, attrs: &CodegenFnAttrs) {
-    let sect = match attrs.link_section {
-        Some(name) => name,
-        None => return,
-    };
+    let Some(sect) = attrs.link_section else { return };
     unsafe {
         let buf = SmallCStr::new(sect.as_str());
         llvm::LLVMSetSection(llval, buf.as_ptr());

compiler/rustc_codegen_llvm/src/consts.rs

@@ -369,10 +369,9 @@ impl<'ll> StaticMethods for CodegenCx<'ll, '_> {
         unsafe {
             let attrs = self.tcx.codegen_fn_attrs(def_id);
 
-            let (v, alloc) = match codegen_static_initializer(self, def_id) {
-                Ok(v) => v,
+            let Ok((v, alloc)) = codegen_static_initializer(self, def_id) else {
                 // Error has already been reported
-                Err(_) => return,
+                return;
             };
 
             let g = self.get_static(def_id);

compiler/rustc_codegen_llvm/src/debuginfo/metadata.rs

@@ -766,18 +766,15 @@ pub fn type_metadata<'ll, 'tcx>(cx: &CodegenCx<'ll, 'tcx>, t: Ty<'tcx>) -> &'ll
 
         if already_stored_in_typemap {
             // Also make sure that we already have a `TypeMap` entry for the unique type ID.
-            let metadata_for_uid = match type_map.find_metadata_for_unique_id(unique_type_id) {
-                Some(metadata) => metadata,
-                None => {
-                    bug!(
-                        "expected type metadata for unique \
-                               type ID '{}' to already be in \
-                               the `debuginfo::TypeMap` but it \
-                               was not. (Ty = {})",
-                        type_map.get_unique_type_id_as_string(unique_type_id),
-                        t
-                    );
-                }
+            let Some(metadata_for_uid) = type_map.find_metadata_for_unique_id(unique_type_id) else {
+                bug!(
+                    "expected type metadata for unique \
+                            type ID '{}' to already be in \
+                            the `debuginfo::TypeMap` but it \
+                            was not. (Ty = {})",
+                    type_map.get_unique_type_id_as_string(unique_type_id),
+                    t
+                );
             };
 
             match type_map.find_metadata_for_type(t) {

compiler/rustc_codegen_llvm/src/intrinsic.rs

@@ -88,9 +88,8 @@ impl<'ll, 'tcx> IntrinsicCallMethods<'tcx> for Builder<'_, 'll, 'tcx> {
         let tcx = self.tcx;
         let callee_ty = instance.ty(tcx, ty::ParamEnv::reveal_all());
 
-        let (def_id, substs) = match *callee_ty.kind() {
-            ty::FnDef(def_id, substs) => (def_id, substs),
-            _ => bug!("expected fn item type, found {}", callee_ty),
+        let ty::FnDef(def_id, substs) = *callee_ty.kind() else {
+            bug!("expected fn item type, found {}", callee_ty);
         };
 
         let sig = callee_ty.fn_sig(tcx);
@@ -1000,9 +999,8 @@ fn generic_simd_intrinsic<'ll, 'tcx>(
                 }
             })
             .collect();
-        let indices = match indices {
-            Some(i) => i,
-            None => return Ok(bx.const_null(llret_ty)),
+        let Some(indices) = indices else {
+            return Ok(bx.const_null(llret_ty));
         };
 
         return Ok(bx.shuffle_vector(

compiler/rustc_codegen_llvm/src/type_of.rs

@@ -339,9 +339,8 @@ impl<'tcx> LayoutLlvmExt<'tcx> for TyAndLayout<'tcx> {
             _ => {}
         }
 
-        let (a, b) = match self.abi {
-            Abi::ScalarPair(a, b) => (a, b),
-            _ => bug!("TyAndLayout::scalar_pair_element_llty({:?}): not applicable", self),
+        let Abi::ScalarPair(a, b) = self.abi else {
+            bug!("TyAndLayout::scalar_pair_element_llty({:?}): not applicable", self);
         };
         let scalar = [a, b][index];