diff --git a/src/core/meta.zig b/src/core/meta.zig
index 582176b..f76f362 100644
--- a/src/core/meta.zig
+++ b/src/core/meta.zig
@@ -48,20 +48,20 @@ pub fn BiFunction(comptime captures_size: usize, comptime A: type,
                 @compileError("`captures` must be smaller than or equal to " ++
                     std.fmt.comptimePrint("{d}", .{captures_size}) ++ " bytes");
 
-            const captures_align = @alignOf(Captures);
-
             var function = Self{
                 .context = undefined,
 
                 .applyErased = struct {
-                    fn do(erased: *anyopaque, a: A, b: B) Out {
-                        return call(@ptrCast(*Captures, @alignCast(
-                            captures_align, erased)).*, a, b);
+                    fn applyErased(erased: *anyopaque, a: A, b: B) Out {
+                        return call(if (Captures == void) {} else @ptrCast(*Captures,
+                            @alignCast(@alignOf(Captures), erased)).*, a, b);
                     }
-                }.do,
+                }.applyErased,
             };
 
-            @ptrCast(*Captures, @alignCast(captures_align, &function.context)).* = captures;
+            if (captures != {}) {
+                @ptrCast(*Captures, @alignCast(@alignOf(Captures), &function.context)).* = captures;
+            }
 
             return function;
         }
@@ -108,11 +108,11 @@ pub fn Function(comptime captures_size: usize, comptime In: type, comptime Out:
                 .context = undefined,
 
                 .applyErased = struct {
-                    fn do(erased: *anyopaque, input: In) Out {
-                        return call(@ptrCast(*Captures, @alignCast(
-                            captures_align, erased)).*, input);
+                    fn applyErased(erased: *anyopaque, input: In) Out {
+                        return call(if (Captures == void) {} else @ptrCast(*Captures,
+                            @alignCast(@alignOf(Captures), erased)).*, input);
                     }
-                }.do,
+                }.applyErased,
             };
 
             @ptrCast(*Captures, @alignCast(captures_align, &function.context)).* = captures;