refactor confusing loop in proc_macro arena

cyrgani · cyrgani · commit 74ec42e000d8 · 2025-10-07T21:21:07.000+02:00
diff --git a/library/proc_macro/src/bridge/arena.rs b/library/proc_macro/src/bridge/arena.rs
@@ -90,14 +90,13 @@ impl Arena {
             return &mut [];
         }
 
-        loop {
-            if let Some(a) = self.alloc_raw_without_grow(bytes) {
-                break a;
-            }
-            // No free space left. Allocate a new chunk to satisfy the request.
-            // On failure the grow will panic or abort.
-            self.grow(bytes);
+        if let Some(a) = self.alloc_raw_without_grow(bytes) {
+            return a;
         }
+        // No free space left. Allocate a new chunk to satisfy the request.
+        // On failure the grow will panic or abort.
+        self.grow(bytes);
+        self.alloc_raw_without_grow(bytes).unwrap()
     }
 
     #[allow(clippy::mut_from_ref)] // arena allocator

Original file line number	Diff line number	Diff line change
`@@ -90,14 +90,13 @@ impl Arena {`
`90`	`90`	`return &mut [];`
`91`	`91`	`}`
`92`	`92`
`93`		`- loop {`
`94`		`- if let Some(a) = self.alloc_raw_without_grow(bytes) {`
`95`		`- break a;`
`96`		`- }`
`97`		`- // No free space left. Allocate a new chunk to satisfy the request.`
`98`		`- // On failure the grow will panic or abort.`
`99`		`- self.grow(bytes);`
	`93`	`+ if let Some(a) = self.alloc_raw_without_grow(bytes) {`
	`94`	`+ return a;`
`100`	`95`	`}`
	`96`	`+ // No free space left. Allocate a new chunk to satisfy the request.`
	`97`	`+ // On failure the grow will panic or abort.`
	`98`	`+ self.grow(bytes);`
	`99`	`+ self.alloc_raw_without_grow(bytes).unwrap()`
`101`	`100`	`}`
`102`	`101`
`103`	`102`	`#[allow(clippy::mut_from_ref)] // arena allocator`