diff --git a/source/vibe/internal/interfaceproxy.d b/source/vibe/internal/interfaceproxy.d
index 74258630..4c8b73db 100644
--- a/source/vibe/internal/interfaceproxy.d
+++ b/source/vibe/internal/interfaceproxy.d
@@ -11,14 +11,14 @@ import std.traits : BaseTypeTuple;
 O asInterface(I, O)(O obj) if (is(I == interface) && is(O : I)) { return obj; }
 InterfaceProxyClass!(I, O) asInterface(I, O)(O obj) if (is(I == interface) && !is(O : I)) { return new InterfaceProxyClass!(I, O)(obj); }
 
-InterfaceProxyClass!(I, O) asInterface(I, O)(O obj, IAllocator allocator)
+InterfaceProxyClass!(I, O) asInterface(I, O, Allocator)(O obj, Allocator allocator)
 @trusted if (is(I == interface) && !is(O : I))
 {
 	alias R = InterfaceProxyClass!(I, O);
 	return allocator.makeGCSafe!R(obj);
 }
 
-void freeInterface(I, O)(InterfaceProxyClass!(I, O) inst, IAllocator allocator)
+void freeInterface(I, O, Allocator)(InterfaceProxyClass!(I, O) inst, Allocator allocator)
 {
 	allocator.disposeGCSafe(inst);
 }
diff --git a/source/vibe/internal/string.d b/source/vibe/internal/string.d
index 6e227dd2..2d838690 100644
--- a/source/vibe/internal/string.d
+++ b/source/vibe/internal/string.d
@@ -182,7 +182,7 @@ ptrdiff_t matchBracket(string str, bool nested = true)
 }
 
 /// Same as std.string.format, just using an allocator.
-string formatAlloc(ARGS...)(IAllocator alloc, string fmt, ARGS args)
+string formatAlloc(Allocator, ARGS...)(Allocator alloc, string fmt, ARGS args)
 {
 	auto app = AllocAppender!string(alloc);
 	formattedWrite(() @trusted { return &app; } (), fmt, args);