Change nogc workarounds to work for older compiler versions.

source/eventcore/drivers/posix/events.d

@@ -171,18 +171,24 @@ final class PosixEventDriverEvents(Loop : PosixEventLoop, Sockets : EventDriverS
 			trigger(event, cnt > 0);
 		}
 	} else {
-		private void onSocketData(DatagramSocketFD s, IOStatus st, size_t, scope RefAddress)
+		private void onSocketData(DatagramSocketFD socket, IOStatus st, size_t, scope RefAddress)
 		@nogc {
 			// avoid infinite recursion in case of errors
 			if (st == IOStatus.ok)
-				m_sockets.receiveNoGC(s, m_buf, IOMode.once, &onSocketData);
+				m_sockets.receiveNoGC(socket, m_buf, IOMode.once, &onSocketData);
 
 			try {
-				EventID evt = m_sockets.userData!EventID(s);
-				scope doit = {
-					trigger(evt, (cast(long[])m_buf)[0] > 1);
-				}; // cast to nogc
-				() @trusted { (cast(void delegate() @nogc)doit)(); } ();
+				EventID evt = m_sockets.userData!EventID(socket);
+				// FIXME: push @nogc further down the call chain instead of
+				//        performing this ugly workaround
+				static struct S {
+					PosixEventDriverEvents this_;
+					EventID evt;
+					bool all;
+					void doit() { this_.trigger(evt, all); }
+				}
+				scope s = S(this, evt, (cast(long[])m_buf)[0] > 1);
+				() @trusted { (cast(void delegate() @nogc)&s.doit)(); } ();
 			} catch (Exception e) assert(false, e.msg);
 		}
 	}

source/eventcore/drivers/posix/sockets.d

@@ -889,10 +889,19 @@ final class PosixEventDriverSockets(Loop : PosixEventLoop) : EventDriverSockets
 
 	package void receiveNoGC(DatagramSocketFD socket, ubyte[] buffer, IOMode mode, void delegate(DatagramSocketFD, IOStatus, size_t, scope RefAddress) @safe nothrow @nogc on_receive_finish)
 	@trusted @nogc {
-		scope void delegate() @safe nothrow do_it = {
-			receive(socket, buffer, mode, on_receive_finish);
-		};
-		(cast(void delegate() @safe nothrow @nogc)do_it)();
+		// FIXME: push @nogc further down the call chain instead of
+		//        performing this ugly workaround
+		static struct S {
+			PosixEventDriverSockets this_;
+			DatagramSocketFD socket;
+			ubyte[] buffer;
+			IOMode mode;
+			void delegate(DatagramSocketFD, IOStatus, size_t, scope RefAddress) @safe nothrow @nogc on_receive_finish;
+			void doit() { this_.receive(socket, buffer, mode, on_receive_finish); }
+
+		}
+		scope s = S(this, socket, buffer, mode, on_receive_finish);
+		(cast(void delegate() @safe nothrow @nogc)&s.doit)();
 	}
 
 	void cancelReceive(DatagramSocketFD socket)

source/eventcore/internal/utils.d

@@ -8,13 +8,23 @@ import taggedalgebraic;
 void print(ARGS...)(string str, ARGS args)
 @trusted @nogc nothrow {
 	import std.format : formattedWrite;
-	StdoutRange r;
-	scope cb = () {
-		try (&r).formattedWrite(str, args);
-		catch (Exception e) assert(false, e.msg);
-	};
-	(cast(void delegate() @nogc @safe nothrow)cb)();
-	r.put('\n');
+	// NOTE: formattedWrite isn't @nogc, although it could be for the types that
+	//       we actually log. Since printing is only enabled in debug settings,
+	//       @nogc is artificailly enforced here to be able to provice a @nogc
+	//       API.
+	static struct S {
+		string str;
+		ARGS args;
+		StdoutRange r;
+		void doit()
+		{
+			try (&r).formattedWrite(str, args);
+			catch (Exception e) assert(false, e.msg);
+		}
+	}
+	scope s = S(str, args);
+	(cast(void delegate() @nogc @safe nothrow)&s.doit)();
+	s.r.put('\n');
 }
 
 T mallocT(T, ARGS...)(ARGS args)
@@ -75,10 +85,14 @@ void freeNT(T)(ref T[] arr)
 }
 
 private void noGCDestroy(T)(ref T t)
-@trusted {
+@trusted @nogc {
 	// FIXME: only do this if the destructor chain is actually nogc
-	scope doit = { destroy(t); };
-	(cast(void delegate() @nogc)doit)();
+	static struct S {
+		T* pt;
+		void doit() { destroy(*pt); }
+	}
+	scope s = S(&t);
+	(cast(void delegate() @nogc)&s.doit)();
 }
 
 private extern(C) Throwable.TraceInfo _d_traceContext(void* ptr = null);
@@ -94,15 +108,27 @@ void nogc_assert(bool cond, string message, string file = __FILE__, int line = _
 			assert(false);
 		}
 
-		scope doit = {
-			stderr.writefln("Assertion failure @%s(%s): %s", file, line, message);
-			stderr.writeln("------------------------");
-			if (auto info = _d_traceContext(null)) {
-				foreach (s; info)
-					stderr.writeln(s);
-			} else stderr.writeln("no stack trace available");
-		};
-		(cast(void delegate() @nogc)doit)(); // write and _d_traceContext are not nogc
+		// NOTE: writefln isn't @nogc, although it could be for the types that
+		//       we actually log. Since this is only called right before app
+		//       termination, enforcing @nogc is done here to allow keeping the
+		//       API @nogc.
+		static struct S {
+			string message;
+			string file;
+			int line;
+			void doit()
+			{
+				stderr.writefln("Assertion failure @%s(%s): %s", file, line, message);
+				stderr.writeln("------------------------");
+				if (auto info = _d_traceContext(null)) {
+					foreach (s; info)
+						stderr.writeln(s);
+				} else stderr.writeln("no stack trace available");
+			}
+
+		}
+		scope s = S(message, file, line);
+		(cast(void delegate() @nogc)&s.doit)(); // write and _d_traceContext are not nogc
 	}
 }