`rustc_builtin_macros`: remove `ref` patterns

... and other pattern matching improvements

1 files changed, 14 insertions, 18 deletions

diff --git a/compiler/rustc_builtin_macros/src/global_allocator.rs b/compiler/rustc_builtin_macros/src/global_allocator.rs
index 0817aed037e..41531580c19 100644
--- a/compiler/rustc_builtin_macros/src/global_allocator.rs
+++ b/compiler/rustc_builtin_macros/src/global_allocator.rs
@@ -20,27 +20,23 @@ pub fn expand(
     check_builtin_macro_attribute(ecx, meta_item, sym::global_allocator);
 
     let orig_item = item.clone();
-    let not_static = || {
-        ecx.sess.parse_sess.span_diagnostic.span_err(item.span(), "allocators must be statics");
-        vec![orig_item.clone()]
-    };
 
     // Allow using `#[global_allocator]` on an item statement
     // FIXME - if we get deref patterns, use them to reduce duplication here
-    let (item, is_stmt, ty_span) = match &item {
-        Annotatable::Item(item) => match item.kind {
-            ItemKind::Static(ref ty, ..) => (item, false, ecx.with_def_site_ctxt(ty.span)),
-            _ => return not_static(),
-        },
-        Annotatable::Stmt(stmt) => match &stmt.kind {
-            StmtKind::Item(item_) => match item_.kind {
-                ItemKind::Static(ref ty, ..) => (item_, true, ecx.with_def_site_ctxt(ty.span)),
-                _ => return not_static(),
-            },
-            _ => return not_static(),
-        },
-        _ => return not_static(),
-    };
+    let (item, is_stmt, ty_span) =
+        if let Annotatable::Item(item) = &item
+            && let ItemKind::Static(ty, ..) = &item.kind
+        {
+            (item, false, ecx.with_def_site_ctxt(ty.span))
+        } else if let Annotatable::Stmt(stmt) = &item
+            && let StmtKind::Item(item) = &stmt.kind
+            && let ItemKind::Static(ty, ..) = &item.kind
+        {
+            (item, true, ecx.with_def_site_ctxt(ty.span))
+        } else {
+            ecx.sess.parse_sess.span_diagnostic.span_err(item.span(), "allocators must be statics");
+            return vec![orig_item.clone()]
+        };
 
     // Generate a bunch of new items using the AllocFnFactory
     let span = ecx.with_def_site_ctxt(item.span);