diff --git a/releasenotes.md b/releasenotes.md
index dc885dd02..3384c490b 100644
--- a/releasenotes.md
+++ b/releasenotes.md
@@ -22,6 +22,7 @@
 - Improve `@param` parse errors #1777
 - Improved `#foo` resolution inside of the compiler.
 - Deprecated '&' macro arguments.
+- Deprecate `fn void! main() type main functions.
 
 ### Fixes
 - Fix case trying to initialize a `char[*]*` from a String.
diff --git a/resources/examples/base64.c3 b/resources/examples/base64.c3
index 9a935d886..e856a9735 100644
--- a/resources/examples/base64.c3
+++ b/resources/examples/base64.c3
@@ -120,7 +120,7 @@ fn int! decode(String in, char* out, int* invalid_char_index = null)
 
 extern fn void printf(char *fmt, ...);
 
-fn void! main()
+fn void main()
 {
 	char *helloworld = "Hello World\n";
 	char[1000] buffer;
@@ -128,7 +128,7 @@ fn void! main()
 	printf("Result: %s\n", &buffer);
 	char *to_decode = "aGVsbG8gd29ybGRcMA==";
 	char[*] result = b64"aGVsbG8gd29ybGRcMA==";
-	decode((String)to_decode[0..19], &buffer)!;
+	decode((String)to_decode[0..19], &buffer)!!;
 	printf("Result: %s\n", &buffer);
 	printf("Result direct: %.*s\n", 13, &result);
 }
\ No newline at end of file
diff --git a/resources/examples/brainfk.c3 b/resources/examples/brainfk.c3
index a948dd74e..6f3f89fd3 100644
--- a/resources/examples/brainfk.c3
+++ b/resources/examples/brainfk.c3
@@ -73,7 +73,7 @@ fn void! brainf(String program)
 		}
 	}
 }
-fn void! main()
+fn void main()
 {
 	String program = `
 	++++[>+++++<-]>[<+++++>-]+<+[
@@ -81,5 +81,5 @@ fn void! main()
         >>>+[[-]++++++>>>]<<<[[<++++++++<++>>-]+<.<[>----<-]<]
         <<[>>>>>[>>>[-]+++++++++<[>-<-]+++++++++>[-[<->-]+[<<<]]<[>+<-]>]<<-]<<-
     ]`;
-    brainf(program)!;
+    brainf(program)!!;
 }
\ No newline at end of file
diff --git a/resources/examples/contextfree/cleanup.c3 b/resources/examples/contextfree/cleanup.c3
index bdb1c7ea6..1d2b96618 100644
--- a/resources/examples/contextfree/cleanup.c3
+++ b/resources/examples/contextfree/cleanup.c3
@@ -44,9 +44,9 @@ fn Resource! prep_out(String out_name, String[] prep_names)
 	return writer;
 }
 
-fn void! main()
+fn void main()
 {
-	Resource writer = prep_out("out", String[] { "a", "b"})!;
+	Resource writer = prep_out("out", String[] { "a", "b"});
     defer writer.deinit();
     io::printn("use out");
 }
\ No newline at end of file
diff --git a/resources/examples/contextfree/guess_number.c3 b/resources/examples/contextfree/guess_number.c3
index fb77eed39..b53ae70b8 100644
--- a/resources/examples/contextfree/guess_number.c3
+++ b/resources/examples/contextfree/guess_number.c3
@@ -67,7 +67,7 @@ fn void Game.update(Game *game, int guess)
 	game.guesses++;
 }
 
-fn void! main()
+fn void main()
 {
 	int high = 100;
 	int answer = rand(high) + 1;
diff --git a/resources/examples/fannkuch-redux2.c3 b/resources/examples/fannkuch-redux2.c3
index b561c833d..a6c5b43c6 100644
--- a/resources/examples/fannkuch-redux2.c3
+++ b/resources/examples/fannkuch-redux2.c3
@@ -63,7 +63,7 @@ fn int fannkuchredux(int n)
 	}
 }
 
-fn void! main(String[] argv)
+fn void main(String[] argv)
 {
 	int n = argv.len > 1 ? argv[1].to_int()!! : 7;
 	io::printf("Pfannkuchen(%d) = %d\n", n, fannkuchredux(n));
diff --git a/resources/examples/load_world.c3 b/resources/examples/load_world.c3
index 09bd5f063..085bc919e 100644
--- a/resources/examples/load_world.c3
+++ b/resources/examples/load_world.c3
@@ -1,11 +1,11 @@
 module load_world;
 import std::io;
-fn void! main()
+fn void main()
 {
-	File f = file::open("examples/hello_world.txt", "rb")!;
+	File f = file::open("examples/hello_world.txt", "rb")!!;
 	defer f.close()!!;
 	while (!f.eof())
 	{
-		@pool() { io::printn(io::treadline(&f)!); };
+		@pool() { io::printn(io::treadline(&f)!!); };
 	}
 }
\ No newline at end of file
diff --git a/resources/examples/plus_minus.c3 b/resources/examples/plus_minus.c3
index 665b6cf7e..6dc65190f 100644
--- a/resources/examples/plus_minus.c3
+++ b/resources/examples/plus_minus.c3
@@ -10,10 +10,10 @@ fault TokenResult
 
 // While we could have written this with libc
 // the C way, let's showcase some features added to C3.
-fn void! main(String[] args)
+fn void main(String[] args)
 {
 	// Grab a string from stdin
-	String s = io::readline()!;
+	String s = io::readline()!!;
 	// Delete it at scope end [defer]
 	defer s.free();
 
diff --git a/resources/examples/process.c3 b/resources/examples/process.c3
index e633ebb1f..532beeb3e 100644
--- a/resources/examples/process.c3
+++ b/resources/examples/process.c3
@@ -2,11 +2,11 @@ module test;
 import std::os::process;
 import std::io;
 
-fn void! main()
+fn void main()
 {
 	String command = env::WIN32 ? "dir" : "ls";
 	SubProcess x = process::create({ command }, { .search_user_path = true })!!;
-	x.join()!;
+	x.join()!!;
 	InStream stream = &&x.stdout();
 	while (try char b = stream.read_byte())
 	{
diff --git a/src/compiler/ast.c b/src/compiler/ast.c
index 8552cb084..5b7cf961f 100644
--- a/src/compiler/ast.c
+++ b/src/compiler/ast.c
@@ -147,7 +147,7 @@ const char *decl_to_a_name(Decl *decl)
 				case VARDECL_PARAM_CT: return "a compile time parameter";
 				case VARDECL_PARAM_CT_TYPE: return "a compile time type parameter";
 				case VARDECL_PARAM_EXPR: return "a expression parameter";
-				case VARDECL_PARAM_REF: return "a ref parameter";
+				case VARDECL_PARAM_REF: return "a ref parameter"; // DEPRECATED
 				case VARDECL_REWRAPPED: UNREACHABLE
 				case VARDECL_UNWRAPPED: return "an unwrapped variable";
 			}
@@ -373,7 +373,7 @@ bool decl_is_global(Decl *ident)
 		case VARDECL_PARAM:
 		case VARDECL_MEMBER:
 		case VARDECL_BITMEMBER:
-		case VARDECL_PARAM_REF:
+		case VARDECL_PARAM_REF: // DEPRECATED
 		case VARDECL_PARAM_EXPR:
 		case VARDECL_UNWRAPPED:
 		case VARDECL_ERASE:
diff --git a/src/compiler/c_codegen.c b/src/compiler/c_codegen.c
index 92f2ec908..8af3f5e66 100644
--- a/src/compiler/c_codegen.c
+++ b/src/compiler/c_codegen.c
@@ -634,7 +634,7 @@ static void c_emit_local_decl(GenContext *c, Decl *decl, CValue *value)
 		case VARDECL_BITMEMBER:
 			UNREACHABLE;
 		case VARDECL_PARAM:
-		case VARDECL_PARAM_REF:
+		case VARDECL_PARAM_REF: // DEPRECATED
 		{
 			PRINT("/* LOCAL DECL */\n");
 /*
diff --git a/src/compiler/compiler_internal.h b/src/compiler/compiler_internal.h
index cff77f3bf..5397c17a5 100644
--- a/src/compiler/compiler_internal.h
+++ b/src/compiler/compiler_internal.h
@@ -3980,7 +3980,7 @@ static inline bool decl_is_var_local(Decl *decl)
 		   || kind == VARDECL_LOCAL
 		   || kind == VARDECL_LOCAL_CT_TYPE
 		   || kind == VARDECL_LOCAL_CT
-		   || kind == VARDECL_PARAM_REF
+		   || kind == VARDECL_PARAM_REF // DEPRECATED
 		   || kind == VARDECL_PARAM_EXPR
 		   || kind == VARDECL_BITMEMBER
 		   || kind == VARDECL_MEMBER;
diff --git a/src/compiler/expr.c b/src/compiler/expr.c
index 22ac107c0..2d456e3a1 100644
--- a/src/compiler/expr.c
+++ b/src/compiler/expr.c
@@ -102,7 +102,7 @@ bool expr_may_addr(Expr *expr)
 				case VARDECL_LOCAL:
 				case VARDECL_GLOBAL:
 				case VARDECL_PARAM:
-				case VARDECL_PARAM_REF:
+				case VARDECL_PARAM_REF: // DEPRECATED
 				case VARDECL_CONST:
 					return true;
 				case VARDECL_MEMBER:
@@ -462,7 +462,7 @@ static inline bool expr_unary_addr_is_constant_eval(Expr *expr)
 				case VARDECL_BITMEMBER:
 				case VARDECL_PARAM_CT:
 				case VARDECL_PARAM_CT_TYPE:
-				case VARDECL_PARAM_REF:
+				case VARDECL_PARAM_REF: // DEPRECATED
 				case VARDECL_PARAM_EXPR:
 				case VARDECL_LOCAL_CT:
 				case VARDECL_LOCAL_CT_TYPE:
diff --git a/src/compiler/llvm_codegen_expr.c b/src/compiler/llvm_codegen_expr.c
index 60e25ec2e..22794bb38 100644
--- a/src/compiler/llvm_codegen_expr.c
+++ b/src/compiler/llvm_codegen_expr.c
@@ -6142,7 +6142,7 @@ static inline void llvm_emit_macro_block(GenContext *c, BEValue *be_value, Expr
 			case VARDECL_PARAM_CT_TYPE:
 			case VARDECL_PARAM_EXPR:
 				continue;
-			case VARDECL_PARAM_REF:
+			case VARDECL_PARAM_REF: // DEPRECATED
 			case VARDECL_PARAM:
 				break;
 		}
diff --git a/src/compiler/llvm_codegen_stmt.c b/src/compiler/llvm_codegen_stmt.c
index 42773304b..9cdf0268b 100644
--- a/src/compiler/llvm_codegen_stmt.c
+++ b/src/compiler/llvm_codegen_stmt.c
@@ -82,8 +82,8 @@ void llvm_emit_local_decl(GenContext *c, Decl *decl, BEValue *value)
 		case VARDECL_MEMBER:
 		case VARDECL_BITMEMBER:
 			UNREACHABLE;
+		case VARDECL_PARAM_REF: // DEPRECATED
 		case VARDECL_PARAM:
-		case VARDECL_PARAM_REF:
 		{
 			Expr *init_expr = decl->var.init_expr;
 			llvm_emit_expr(c, value, init_expr);
diff --git a/src/compiler/sema_decls.c b/src/compiler/sema_decls.c
index ea631f14b..14accfdfa 100755
--- a/src/compiler/sema_decls.c
+++ b/src/compiler/sema_decls.c
@@ -3423,11 +3423,12 @@ static inline bool sema_analyse_main_function(SemaContext *context, Decl *decl)
 	{
 		if (rtype->optional->type_kind != TYPE_VOID)
 		{
-			SEMA_ERROR(rtype_info, "The return type of 'main' cannot be an optional, unless it is 'void!'.");
+			RETURN_SEMA_ERROR(rtype_info, "The return type of 'main' cannot be an optional, unless it is 'void!'.");
 			return false;
 		}
 		is_int_return = false;
 		is_err_return = true;
+		SEMA_DEPRECATED(rtype_info, "Main functions with 'void!' returns is deprecated, use 'int' or 'void' instead.");
 	}
 
 	if (type_is_void(rtype)) is_int_return = false;
@@ -3669,16 +3670,20 @@ INLINE bool sema_analyse_macro_body(SemaContext *context, Decl **body_parameters
 		VarDeclKind kind = param->var.kind;
 		switch (kind)
 		{
-			case VARDECL_PARAM:
-			case VARDECL_PARAM_EXPR:
-			case VARDECL_PARAM_CT:
 			case VARDECL_PARAM_REF:
-			case VARDECL_PARAM_CT_TYPE:
+				// DEPRECATED
 				if (!type_info) break;
 				if (!sema_resolve_type_info(context, type_info, RESOLVE_TYPE_DEFAULT)) return false;
 				if (kind != VARDECL_PARAM_REF || type_is_pointer(type_info->type)) break;
 				RETURN_SEMA_ERROR(type_info, "A pointer type was expected for a ref argument, did you mean %s?",
 				                  type_quoted_error_string(type_get_ptr(type_info->type)));
+			case VARDECL_PARAM:
+			case VARDECL_PARAM_EXPR:
+			case VARDECL_PARAM_CT:
+			case VARDECL_PARAM_CT_TYPE:
+				if (!type_info) break;
+				if (!sema_resolve_type_info(context, type_info, RESOLVE_TYPE_DEFAULT)) return false;
+				break;
 			case VARDECL_CONST:
 			case VARDECL_GLOBAL:
 			case VARDECL_LOCAL:
@@ -3797,7 +3802,7 @@ static bool sema_analyse_attributes_for_var(SemaContext *context, Decl *decl, bo
 			domain = ATTR_GLOBAL;
 			break;
 		case VARDECL_PARAM:
-		case VARDECL_PARAM_REF:
+		case VARDECL_PARAM_REF: // DEPRECATED
 		case VARDECL_PARAM_CT_TYPE:
 		case VARDECL_PARAM_CT:
 			domain = ATTR_PARAM;
diff --git a/src/compiler/sema_expr.c b/src/compiler/sema_expr.c
index c31ba76cc..b13593e10 100644
--- a/src/compiler/sema_expr.c
+++ b/src/compiler/sema_expr.c
@@ -10134,6 +10134,7 @@ bool sema_insert_method_call(SemaContext *context, Expr *method_call, Decl *meth
 	// Deref / addr as needed.
 	if (first_param->var.kind == VARDECL_PARAM_REF)
 	{
+		// DEPRECATED
 		ASSERT_SPAN(method_call, first->type_kind == TYPE_POINTER);
 		first = first->pointer;
 	}
@@ -10150,6 +10151,7 @@ bool sema_insert_method_call(SemaContext *context, Expr *method_call, Decl *meth
 	}
 	else if (first_param->var.kind == VARDECL_PARAM_REF || !expr_may_ref(parent))
 	{
+		// DEPRECATED
 		Expr *inner = expr_copy(parent);
 		parent->expr_kind = EXPR_UNARY;
 		Type *inner_type = inner->type;
diff --git a/src/compiler/sema_liveness.c b/src/compiler/sema_liveness.c
index 8b68c2cc8..e2c66b909 100644
--- a/src/compiler/sema_liveness.c
+++ b/src/compiler/sema_liveness.c
@@ -659,8 +659,8 @@ RETRY:
 				case VARDECL_PARAM_EXPR:
 					// These are never traced, they are folded in use.
 					break;
+				case VARDECL_PARAM_REF: // DEPRECATED
 				case VARDECL_PARAM_CT:
-				case VARDECL_PARAM_REF:
 				case VARDECL_PARAM:
 					sema_trace_type_liveness(decl->type);
 					if (decl->var.init_expr && decl->var.init_expr->resolve_status == RESOLVE_DONE)
diff --git a/test/test_suite/any/casting_voidptr_to_any.c3 b/test/test_suite/any/casting_voidptr_to_any.c3
index 154abb335..e4999e63a 100644
--- a/test/test_suite/any/casting_voidptr_to_any.c3
+++ b/test/test_suite/any/casting_voidptr_to_any.c3
@@ -20,7 +20,7 @@ fn void test(void* tptr){
     iop = tptr; // #error: Casting a 'void*' to 'IOp' is not permitted
     iop.op();
 }
-fn void! main(String[] args) {
+fn void main(String[] args) {
     Op(<int>)* t = mem::new(Op(<int>), {.data = 1});
     test(&t);
 }
diff --git a/test/test_suite/arrays/array_bounds_check.c3t b/test/test_suite/arrays/array_bounds_check.c3t
index 433fd9f66..77553df82 100644
--- a/test/test_suite/arrays/array_bounds_check.c3t
+++ b/test/test_suite/arrays/array_bounds_check.c3t
@@ -10,7 +10,7 @@ struct Foo
 	int x;
 }
 
-fn void! main()
+fn void main()
 {
 	for (usz i = 0; i < 20; i++)
 	{
@@ -24,6 +24,7 @@ loop.cond:                                        ; preds = %checkok, %entry
   %0 = load i64, ptr %i, align 8
   %gt = icmp ugt i64 20, %0
   br i1 %gt, label %loop.body, label %loop.exit
+
 loop.body:                                        ; preds = %loop.cond
   %1 = load i64, ptr %i, align 8
   %ge = icmp uge i64 %1, 2
@@ -40,7 +41,7 @@ checkok:                                          ; preds = %loop.body
   br label %loop.cond
 
 loop.exit:                                        ; preds = %loop.cond
-  ret i64 0
+  ret void
 
 panic:                                            ; preds = %loop.body
   store i64 2, ptr %taddr, align 8
diff --git a/test/test_suite/assert/assert_with_void.c3 b/test/test_suite/assert/assert_with_void.c3
index 671803880..1725e0bd2 100644
--- a/test/test_suite/assert/assert_with_void.c3
+++ b/test/test_suite/assert/assert_with_void.c3
@@ -1,7 +1,7 @@
 module testing;
 import std::io;
 
-fn void! main()
+fn void main()
 {
     String[] s1;
     String[] s2;
diff --git a/test/test_suite/assert/assertf.c3t b/test/test_suite/assert/assertf.c3t
index bcbe59204..4920c5979 100644
--- a/test/test_suite/assert/assertf.c3t
+++ b/test/test_suite/assert/assertf.c3t
@@ -2,7 +2,7 @@
 // #safe: yes
 module main;
 
-fn void! main()
+fn void main()
 {
 	for (usz i = 0; i < 100000000; i++)
 	{
@@ -12,8 +12,6 @@ fn void! main()
 
 /* #expect: main.ll
 
-define i64 @main.main() #0 {
-entry:
   %i = alloca i64, align 8
   %taddr = alloca i64, align 8
   %varargslots = alloca [2 x %any], align 16
@@ -50,6 +48,4 @@ assert_ok:                                        ; preds = %loop.body
   store i64 %add, ptr %i, align 8
   br label %loop.cond
 loop.exit:                                        ; preds = %loop.cond
-  ret i64 0
-}
 
diff --git a/test/test_suite/bitstruct/bitstruct_in_subarray.c3t b/test/test_suite/bitstruct/bitstruct_in_subarray.c3t
index bb264a6a2..0e5396d88 100644
--- a/test/test_suite/bitstruct/bitstruct_in_subarray.c3t
+++ b/test/test_suite/bitstruct/bitstruct_in_subarray.c3t
@@ -6,14 +6,15 @@ bitstruct StructFieldKind : char
     bool is_union : 1;
 }
 
-fn void! main()
+fn void main()
 {
     StructFieldKind[] xx = { { .is_union = true } };
 }
 
 /* #expect: test.ll
 
-define i64 @test.main() #0 {
+
+define void @test.main() #0 {
 entry:
   %xx = alloca %"char[]", align 8
   %literal = alloca [1 x i8], align 1
@@ -21,5 +22,5 @@ entry:
   %0 = insertvalue %"char[]" undef, ptr %literal, 0
   %1 = insertvalue %"char[]" %0, i64 1, 1
   store %"char[]" %1, ptr %xx, align 8
-  ret i64 0
+  ret void
 }
\ No newline at end of file
diff --git a/test/test_suite/cast/cast_bitstruct_etc.c3t b/test/test_suite/cast/cast_bitstruct_etc.c3t
index e34922498..daee17bd4 100644
--- a/test/test_suite/cast/cast_bitstruct_etc.c3t
+++ b/test/test_suite/cast/cast_bitstruct_etc.c3t
@@ -1,7 +1,7 @@
 // #target: macos-x64
 module test;
 
-fn void! main()
+fn void main()
 {
 	Enum e = ENUM1;
 	ushort x = (ushort)Foo{ .x = e };
@@ -32,5 +32,3 @@ bitstruct Foo : ushort
   %zext1 = zext i8 %2 to i16
   %3 = and i16 %zext1, 255
   store i16 %3, ptr %z, align 2
-  ret i64 0
-}
\ No newline at end of file
diff --git a/test/test_suite/cast/cast_narrow_alias.c3t b/test/test_suite/cast/cast_narrow_alias.c3t
index c8c06de5e..c20d40af7 100644
--- a/test/test_suite/cast/cast_narrow_alias.c3t
+++ b/test/test_suite/cast/cast_narrow_alias.c3t
@@ -1,7 +1,7 @@
 // #target: macos-x64
 module abc;
 def UInt8 = char;
-fn void! main()
+fn void main()
 {
 	UInt8 x = 17;
 	UInt8 y = 5;
@@ -9,7 +9,6 @@ fn void! main()
 }
 /* #expect: abc.ll
 
-define i64 @abc.main() #0 {
 entry:
   %x = alloca i8, align 1
   %y = alloca i8, align 1
@@ -25,5 +24,3 @@ entry:
   %and = and i32 %2, 1
   %trunc = trunc i32 %and to i8
   store i8 %trunc, ptr %z, align 1
-  ret i64 0
-}
diff --git a/test/test_suite/compile_time/ct_assert_bug.c3 b/test/test_suite/compile_time/ct_assert_bug.c3
index a5a6370c0..5b6582bbc 100644
--- a/test/test_suite/compile_time/ct_assert_bug.c3
+++ b/test/test_suite/compile_time/ct_assert_bug.c3
@@ -2,7 +2,7 @@
 module testing;
 import std::io;
 
-fn void! main()
+fn void main()
 {
     String[] s1;
     String[] s2;
diff --git a/test/test_suite/compile_time_introspection/defined_2.c3t b/test/test_suite/compile_time_introspection/defined_2.c3t
index 743cba38f..fec0f75d8 100644
--- a/test/test_suite/compile_time_introspection/defined_2.c3t
+++ b/test/test_suite/compile_time_introspection/defined_2.c3t
@@ -3,7 +3,7 @@
 module testing;
 import std::io;
 
-fn void! main()
+fn void main()
 {
     Bits b1;
     Bits b2;
@@ -22,7 +22,6 @@ fn bool Bits.equals(a, Bits b)
 
 /* #expect: testing.ll
 
-define i64 @testing.main() #0 {
 entry:
   %b1 = alloca i8, align 1
   %b2 = alloca i8, align 1
@@ -39,5 +38,3 @@ entry:
   %3 = load i8, ptr %b, align 1
   %4 = call i8 @testing.Bits.equals(i8 zeroext %2, i8 zeroext %3)
   store i8 %4, ptr %x, align 1
-  ret i64 0
-}
\ No newline at end of file
diff --git a/test/test_suite/constants/constant_struct.c3 b/test/test_suite/constants/constant_struct.c3
index 109b79ae9..2bb0f1190 100644
--- a/test/test_suite/constants/constant_struct.c3
+++ b/test/test_suite/constants/constant_struct.c3
@@ -12,7 +12,7 @@ struct Bcd
 
 const Abc FOO = { 2 };
 
-fn void! main()
+fn void main()
 {
 	Bcd a = { FOO };
 }
diff --git a/test/test_suite/contracts/macro_ensure_static.c3 b/test/test_suite/contracts/macro_ensure_static.c3
index bd4368086..883f5bb36 100644
--- a/test/test_suite/contracts/macro_ensure_static.c3
+++ b/test/test_suite/contracts/macro_ensure_static.c3
@@ -8,7 +8,7 @@ macro check(int a)
 	if (a < 0) return -1; // #error: @ensure
 	return 100;
 }
-fn void! main()
+fn void main()
 {
 	check(43);
 }
\ No newline at end of file
diff --git a/test/test_suite/defer/defer_catch_mix.c3t b/test/test_suite/defer/defer_catch_mix.c3t
index ba7fe7395..20402f275 100644
--- a/test/test_suite/defer/defer_catch_mix.c3t
+++ b/test/test_suite/defer/defer_catch_mix.c3t
@@ -12,7 +12,7 @@ fn char[]! fileReader(String filename, char[] buffer)
     return buffer;
 }
 
-fn void! main()
+fn void main()
 {
     char[] !buffer = mem::new_array(char, 12);
     buffer = fileReader("not_found.txt", buffer);
@@ -232,7 +232,7 @@ voiderr76:                                        ; preds = %noerr_block74, %gua
   ret i64 0
 }
 ; Function Attrs: nounwind uwtable(sync)
-define i64 @test.main() #0 {
+define void @test.main() #0 {
 entry:
   %buffer = alloca %"char[]", align 8
   %buffer.f = alloca i64, align 8
@@ -254,7 +254,6 @@ entry:
   %taddr10 = alloca %"any[]", align 8
   %retparam14 = alloca %"char[]", align 8
   %taddr15 = alloca %"char[]", align 8
-  %reterr = alloca i64, align 8
   store ptr null, ptr %.cachedtype, align 8
   call void @llvm.memcpy.p0.p0.i32(ptr align 8 %allocator, ptr align 8 @std.core.mem.allocator.thread_allocator, i32 16, i1 false)
   call void @llvm.memcpy.p0.p0.i32(ptr align 8 %allocator1, ptr align 8 %allocator, i32 16, i1 false)
@@ -349,36 +348,11 @@ after_check18:                                    ; preds = %after_check13
   store i64 0, ptr %buffer.f, align 8
   br label %after_assign
 after_assign:                                     ; preds = %after_check18, %assign_optional17, %assign_optional12
-  ret i64 0
+  ret void
 }
-; Function Attrs: nounwind uwtable(sync)
+
 define i32 @main(i32 %0, ptr %1) #0 {
 entry:
-  %blockret = alloca i32, align 4
-  %temp_err = alloca i64, align 8
-  br label %testblock
-testblock:                                        ; preds = %entry
-  %2 = call i64 @test.main()
-  %not_err = icmp eq i64 %2, 0
-  %3 = call i1 @llvm.expect.i1(i1 %not_err, i1 true)
-  br i1 %3, label %after_check, label %assign_optional
-assign_optional:                                  ; preds = %testblock
-  store i64 %2, ptr %temp_err, align 8
-  br label %end_block
-after_check:                                      ; preds = %testblock
-  store i64 0, ptr %temp_err, align 8
-  br label %end_block
-end_block:                                        ; preds = %after_check, %assign_optional
-  %4 = load i64, ptr %temp_err, align 8
-  %i2b = icmp ne i64 %4, 0
-  br i1 %i2b, label %if.then, label %if.exit
-if.then:                                          ; preds = %end_block
-  store i32 1, ptr %blockret, align 4
-  br label %expr_block.exit
-if.exit:                                          ; preds = %end_block
-  store i32 0, ptr %blockret, align 4
-  br label %expr_block.exit
-expr_block.exit:                                  ; preds = %if.exit, %if.then
-  %5 = load i32, ptr %blockret, align 4
-  ret i32 %5
+  call void @test.main()
+  ret i32 0
 }
diff --git a/test/test_suite/dynamic/duplicate_definition.c3 b/test/test_suite/dynamic/duplicate_definition.c3
index 139d90658..5d0e5583e 100644
--- a/test/test_suite/dynamic/duplicate_definition.c3
+++ b/test/test_suite/dynamic/duplicate_definition.c3
@@ -5,7 +5,7 @@ interface Abc
 	fn void abc();
 	fn void abc(); // #error: Duplicate definition
 }
-fn void! main()
+fn void main()
 {
 	Abc* g;
 	g.abc();
diff --git a/test/test_suite/enumerations/introspection_data_error.c3t b/test/test_suite/enumerations/introspection_data_error.c3t
index d20614c2d..6d642f7f2 100644
--- a/test/test_suite/enumerations/introspection_data_error.c3t
+++ b/test/test_suite/enumerations/introspection_data_error.c3t
@@ -6,7 +6,7 @@ enum Boom: int (String a) {
 
 module app;
 import std::io, boom;
-fn void! main(String[] args) {
+fn void main(String[] args) {
 	io::printn(Boom.BOOM);
 }
 /* #expect: boom.ll
diff --git a/test/test_suite/errors/optional_designated.c3 b/test/test_suite/errors/optional_designated.c3
index 866bed82b..ccc65c05a 100644
--- a/test/test_suite/errors/optional_designated.c3
+++ b/test/test_suite/errors/optional_designated.c3
@@ -2,7 +2,7 @@ module foo;
 
 struct Foo { int a; }
 struct Bar { int b; Foo f; }
-fn void! main()
+fn void main()
 {
 	Bar { .f = Foo { foo() } }; // #error: not be discarded
 }
diff --git a/test/test_suite/expressions/incdec_overload.c3t b/test/test_suite/expressions/incdec_overload.c3t
index a9a6fa585..fefc8c27b 100644
--- a/test/test_suite/expressions/incdec_overload.c3t
+++ b/test/test_suite/expressions/incdec_overload.c3t
@@ -4,20 +4,19 @@ import std;
 
 def Abc = HashMap(<int, int>);
 Abc m;
-fn void! main()
+fn void main()
 {
 	m[3] = 100;
 	int! x = m[3]--;
-	assert(m[3]! == 99);
-	assert(x! == 100);
+	assert(m[3]!! == 99);
+	assert(x!! == 100);
 	x = ++m[3];
-	assert(m[3]! == 100);
-	assert(x! == 100);
+	assert(m[3]!! == 100);
+	assert(x!! == 100);
 }
 
 /* #expect: test.ll
 
-define i64 @test.main() #0 {
 entry:
   %x = alloca i32, align 4
   %x.f = alloca i64, align 8
@@ -176,44 +175,5 @@ after_check43:                                    ; preds = %after_check39
   br label %after_assign44
 
 after_assign44:                                   ; preds = %after_check43, %assign_optional42, %assign_optional38, %optional_assign_jump33, %optional_assign_jump24
-  ret i64 0
+  ret void
 }
-
-; Function Attrs: nounwind uwtable
-define i32 @main(i32 %0, ptr %1) #0 {
-entry:
-  %blockret = alloca i32, align 4
-  %temp_err = alloca i64, align 8
-  br label %testblock
-
-testblock:                                        ; preds = %entry
-  %2 = call i64 @test.main()
-  %not_err = icmp eq i64 %2, 0
-  %3 = call i1 @llvm.expect.i1(i1 %not_err, i1 true)
-  br i1 %3, label %after_check, label %assign_optional
-
-assign_optional:                                  ; preds = %testblock
-  store i64 %2, ptr %temp_err, align 8
-  br label %end_block
-
-after_check:                                      ; preds = %testblock
-  store i64 0, ptr %temp_err, align 8
-  br label %end_block
-
-end_block:                                        ; preds = %after_check, %assign_optional
-  %4 = load i64, ptr %temp_err, align 8
-  %i2b = icmp ne i64 %4, 0
-  br i1 %i2b, label %if.then, label %if.exit
-
-if.then:                                          ; preds = %end_block
-  store i32 1, ptr %blockret, align 4
-  br label %expr_block.exit
-
-if.exit:                                          ; preds = %end_block
-  store i32 0, ptr %blockret, align 4
-  br label %expr_block.exit
-
-expr_block.exit:                                  ; preds = %if.exit, %if.then
-  %5 = load i32, ptr %blockret, align 4
-  ret i32 %5
-}
\ No newline at end of file
diff --git a/test/test_suite/expressions/optional_and_error.c3 b/test/test_suite/expressions/optional_and_error.c3
index e9861d494..aa9ce69ed 100644
--- a/test/test_suite/expressions/optional_and_error.c3
+++ b/test/test_suite/expressions/optional_and_error.c3
@@ -1,7 +1,7 @@
 module testing;
 import std::io;
 
-fn void! main()
+fn void main()
 {
     bool ok;
     if (ok && !foo()) io::printfn("nok"); // #error: The expression may not be an optional
diff --git a/test/test_suite/functions/function_alias_llvm_check.c3t b/test/test_suite/functions/function_alias_llvm_check.c3t
index 7214c2e14..bc95ffdb8 100644
--- a/test/test_suite/functions/function_alias_llvm_check.c3t
+++ b/test/test_suite/functions/function_alias_llvm_check.c3t
@@ -24,7 +24,7 @@ fn void Foo.add_fn_b(&self, FnB f) => self.bFuncs.push(f);
 fn void a_func(Foo* foo) {}
 fn void b_func(Foo* foo) {}
 
-fn void! main()
+fn void main()
 {
     Foo foo;
     defer foo.deinit()!!;
@@ -34,7 +34,8 @@ fn void! main()
 
 /* #expect: repro.ll
 
-define i64 @repro.main() #0 {
+
+define void @repro.main() #0 {
 entry:
   %foo = alloca %Foo, align 8
   %error_var = alloca i64, align 8
diff --git a/test/test_suite/functions/recursive_through_generic.c3 b/test/test_suite/functions/recursive_through_generic.c3
index 919fac100..ebdb41ff8 100644
--- a/test/test_suite/functions/recursive_through_generic.c3
+++ b/test/test_suite/functions/recursive_through_generic.c3
@@ -1,7 +1,7 @@
 module oups;
 import std::collections::map;
 
-fn void! main()
+fn void main()
 {
 }
 
diff --git a/test/test_suite/generic/generic_builtin.c3t b/test/test_suite/generic/generic_builtin.c3t
index baaa28f29..5643b3c2d 100644
--- a/test/test_suite/generic/generic_builtin.c3t
+++ b/test/test_suite/generic/generic_builtin.c3t
@@ -9,7 +9,7 @@ fn int iadd(int a, int b) @builtin =>
 module main;
 import std::io, add, iadd;
 
-fn void! main()
+fn void main()
 {
   io::printfn("%s", iadd(1,2)); // Fine
   io::printfn("%s", add(<int>)(1,2)); // Error
diff --git a/test/test_suite/generic/generic_lambda_complex.c3t b/test/test_suite/generic/generic_lambda_complex.c3t
index cb9239391..90b686df6 100644
--- a/test/test_suite/generic/generic_lambda_complex.c3t
+++ b/test/test_suite/generic/generic_lambda_complex.c3t
@@ -154,12 +154,12 @@ struct Bar
 	String bar;
 }
 
-fn void! main()
+fn void main()
 {
 
 	String foo_tmpl = "<<{{foo}} | {{bar}}>>";
 	FooTmpl ft;
-	ft.init(foo_tmpl, using: allocator::temp())!;
+	ft.init(foo_tmpl, using: allocator::temp())!!;
 	defer ft.free()!!;
 
 
@@ -167,18 +167,18 @@ fn void! main()
 
 /* #expect: text_test.ll
 
-
-
-define i64 @text_test.main() #0 {
+define void @text_test.main() #0 {
 entry:
   %foo_tmpl = alloca %"char[]", align 8
   %ft = alloca %TextTemplate, align 8
   %error_var = alloca i64, align 8
   %indirectarg = alloca %"char[]", align 8
   %indirectarg1 = alloca %any, align 8
-  %error_var2 = alloca i64, align 8
   %varargslots = alloca [1 x %any], align 16
-  %indirectarg6 = alloca %"any[]", align 8
+  %indirectarg2 = alloca %"any[]", align 8
+  %error_var3 = alloca i64, align 8
+  %varargslots8 = alloca [1 x %any], align 16
+  %indirectarg10 = alloca %"any[]", align 8
   store %"char[]" { ptr @.str, i64 21 }, ptr %foo_tmpl, align 8
   call void @llvm.memset.p0.i64(ptr align 8 %ft, i8 0, i64 72, i1 false)
   %0 = load ptr, ptr @std.core.mem.allocator.thread_temp_allocator, align 8
@@ -205,38 +205,44 @@ if.exit:                                          ; preds = %if.then, %entry
 
 assign_optional:                                  ; preds = %if.exit
   store i64 %4, ptr %error_var, align 8
-  br label %guard_block
+  br label %panic_block
 
 after_check:                                      ; preds = %if.exit
   br label %noerr_block
 
-guard_block:                                      ; preds = %assign_optional
-  %6 = load i64, ptr %error_var, align 8
-  ret i64 %6
-
-noerr_block:                                      ; preds = %after_check
-  %7 = call i64 @"abc$text_test.Foo$.TextTemplate.free"(ptr %ft)
-  %not_err3 = icmp eq i64 %7, 0
-  %8 = call i1 @llvm.expect.i1(i1 %not_err3, i1 true)
-  br i1 %8, label %after_check5, label %assign_optional4
-
-assign_optional4:                                 ; preds = %noerr_block
-  store i64 %7, ptr %error_var2, align 8
-  br label %panic_block
-
-after_check5:                                     ; preds = %noerr_block
-  br label %noerr_block7
-
-panic_block:                                      ; preds = %assign_optional4
-  %9 = insertvalue %any undef, ptr %error_var2, 0
-  %10 = insertvalue %any %9, i64 ptrtoint (ptr @"$ct.anyfault" to i64), 1
-  store %any %10, ptr %varargslots, align 16
-  %11 = insertvalue %"any[]" undef, ptr %varargslots, 0
-  %"$$temp" = insertvalue %"any[]" %11, i64 1, 1
-  store %"any[]" %"$$temp", ptr %indirectarg6, align 8
-  call void @std.core.builtin.panicf(ptr @.panic_msg, i64 36, ptr @.file, i64 25
+panic_block:                                      ; preds = %assign_optional
+  %6 = insertvalue %any undef, ptr %error_var, 0
+  %7 = insertvalue %any %6, i64 ptrtoint (ptr @"$ct.anyfault" to i64), 1
+  store %any %7, ptr %varargslots, align 16
+  %8 = insertvalue %"any[]" undef, ptr %varargslots, 0
+  %"$$temp" = insertvalue %"any[]" %8, i64 1, 1
+  store %"any[]" %"$$temp", ptr %indirectarg2, align 8
+  call void @std.core.builtin.panicf(ptr @.panic_msg, i64 36, ptr @.file, i64 25, ptr @.func, i64 4, i32 161, ptr byval(%"any[]") align 8 %indirectarg2)
   unreachable
 
-noerr_block7:                                     ; preds = %after_check5
-  ret i64 0
+noerr_block:                                      ; preds = %after_check
+  %9 = call i64 @"abc$text_test.Foo$.TextTemplate.free"(ptr %ft)
+  %not_err4 = icmp eq i64 %9, 0
+  %10 = call i1 @llvm.expect.i1(i1 %not_err4, i1 true)
+  br i1 %10, label %after_check6, label %assign_optional5
+
+assign_optional5:                                 ; preds = %noerr_block
+  store i64 %9, ptr %error_var3, align 8
+  br label %panic_block7
+
+after_check6:                                     ; preds = %noerr_block
+  br label %noerr_block11
+
+panic_block7:                                     ; preds = %assign_optional5
+  %11 = insertvalue %any undef, ptr %error_var3, 0
+  %12 = insertvalue %any %11, i64 ptrtoint (ptr @"$ct.anyfault" to i64), 1
+  store %any %12, ptr %varargslots8, align 16
+  %13 = insertvalue %"any[]" undef, ptr %varargslots8, 0
+  %"$$temp9" = insertvalue %"any[]" %13, i64 1, 1
+  store %"any[]" %"$$temp9", ptr %indirectarg10, align 8
+  call void @std.core.builtin.panicf(ptr @.panic_msg, i64 36, ptr @.file, i64 25, ptr @.func, i64 4, i32 162, ptr byval(%"any[]") align 8 %indirectarg10)
+  unreachable
+
+noerr_block11:                                    ; preds = %after_check6
+  ret void
 }
diff --git a/test/test_suite/import/import_twice.c3 b/test/test_suite/import/import_twice.c3
index da7fed2ec..815d41040 100644
--- a/test/test_suite/import/import_twice.c3
+++ b/test/test_suite/import/import_twice.c3
@@ -2,7 +2,7 @@ module foo;
 import std::io;
 import std::io; // #error: imported more than
 
-fn void! main()
+fn void main()
 {
 	io::printn("Hello world");
 }
diff --git a/test/test_suite/macros/implicit_return_opt.c3 b/test/test_suite/macros/implicit_return_opt.c3
index d92ffb5d6..91c5cb20e 100644
--- a/test/test_suite/macros/implicit_return_opt.c3
+++ b/test/test_suite/macros/implicit_return_opt.c3
@@ -1,9 +1,9 @@
 module test;
 import std::io;
 
-fn void! main()
+fn void main()
 {
-	int x = run()!; // #error: You cannot cast
+	int x = run()!!; // #error: You cannot cast
 	io::printfn("x=%d", x);
 }
 
diff --git a/test/test_suite/macros/macro_body_defer.c3t b/test/test_suite/macros/macro_body_defer.c3t
index e20d0e336..a3fae041b 100644
--- a/test/test_suite/macros/macro_body_defer.c3t
+++ b/test/test_suite/macros/macro_body_defer.c3t
@@ -17,7 +17,7 @@ macro foo_defer()
 	printf("B\n");
 	defer printf("C\n");
 }
-fn void! main()
+fn void main()
 {
     foo_defer();
 	@foo_test(34) {
@@ -54,10 +54,8 @@ entry:
   store i32 1, ptr %0, align 4
   ret i64 0
 }
-
-define i64 @foo.main() #0 {
+define void @foo.main() #0 {
 entry:
-  %reterr = alloca i64, align 8
   call void (ptr, ...) @printf(ptr @.str)
   call void (ptr, ...) @printf(ptr @.str.1)
   call void (ptr, ...) @printf(ptr @.str.2)
@@ -65,61 +63,25 @@ entry:
   call void (ptr, ...) @printf(ptr @.str.4, i32 34)
   call void (ptr, ...) @printf(ptr @.str.5, i32 34)
   br label %loop.body
-
 loop.body:                                        ; preds = %entry
   call void (ptr, ...) @printf(ptr @.str.6)
   call void (ptr, ...) @printf(ptr @.str.7)
   call void (ptr, ...) @printf(ptr @.str.8, i32 3)
   call void (ptr, ...) @printf(ptr @.str.9)
   br label %loop.exit
-
 loop.exit:                                        ; preds = %loop.body
   br label %loop.body1
-
 loop.body1:                                       ; preds = %loop.exit
   call void (ptr, ...) @printf(ptr @.str.10)
   call void (ptr, ...) @printf(ptr @.str.11)
   call void (ptr, ...) @printf(ptr @.str.12)
   call void (ptr, ...) @printf(ptr @.str.13, i32 3)
   call void (ptr, ...) @printf(ptr @.str.14)
-  ret i64 0
+  ret void
 }
 
-
 define i32 @main(i32 %0, ptr %1) #0 {
 entry:
-  %blockret = alloca i32, align 4
-  %temp_err = alloca i64, align 8
-  br label %testblock
-
-testblock:                                        ; preds = %entry
-  %2 = call i64 @foo.main()
-  %not_err = icmp eq i64 %2, 0
-  %3 = call i1 @llvm.expect.i1(i1 %not_err, i1 true)
-  br i1 %3, label %after_check, label %assign_optional
-
-assign_optional:                                  ; preds = %testblock
-  store i64 %2, ptr %temp_err, align 8
-  br label %end_block
-
-after_check:                                      ; preds = %testblock
-  store i64 0, ptr %temp_err, align 8
-  br label %end_block
-
-end_block:                                        ; preds = %after_check, %assign_optional
-  %4 = load i64, ptr %temp_err, align 8
-  %i2b = icmp ne i64 %4, 0
-  br i1 %i2b, label %if.then, label %if.exit
-
-if.then:                                          ; preds = %end_block
-  store i32 1, ptr %blockret, align 4
-  br label %expr_block.exit
-
-if.exit:                                          ; preds = %end_block
-  store i32 0, ptr %blockret, align 4
-  br label %expr_block.exit
-
-expr_block.exit:                                  ; preds = %if.exit, %if.then
-  %5 = load i32, ptr %blockret, align 4
-  ret i32 %5
+  call void @foo.main()
+  ret i32 0
 }
diff --git a/test/test_suite/macros/unifying_implicit_void.c3t b/test/test_suite/macros/unifying_implicit_void.c3t
index 319c69343..4c815c827 100644
--- a/test/test_suite/macros/unifying_implicit_void.c3t
+++ b/test/test_suite/macros/unifying_implicit_void.c3t
@@ -2,11 +2,11 @@
 module oups;
 import std::io;
 
-fn void! main()
+fn void main()
 {
 	ByteReader r;
 	InStream s = &r;
-	s.foo()!;
+	s.foo()!!;
 }
 
 macro InStream.foo(&self)
@@ -22,8 +22,7 @@ macro InStream.foo(&self)
 
 /* #expect: oups.ll
 
-
-define i64 @oups.main() #0 {
+define void @oups.main() #0 {
 entry:
   %r = alloca %ByteReader, align 8
   %s = alloca %any, align 8
@@ -34,6 +33,8 @@ entry:
   %.cachedtype = alloca ptr, align 8
   %retparam = alloca i8, align 1
   %err = alloca i64, align 8
+  %varargslots = alloca [1 x %any], align 16
+  %indirectarg = alloca %"any[]", align 8
   store ptr null, ptr %.cachedtype, align 8
   call void @llvm.memset.p0.i64(ptr align 8 %r, i8 0, i64 24, i1 false)
   %0 = insertvalue %any undef, ptr %r, 0
@@ -97,12 +98,18 @@ end_block:                                        ; preds = %after_check4, %assi
 if.then:                                          ; preds = %end_block
   %16 = load i64, ptr %err, align 8
   store i64 %16, ptr %error_var, align 8
-  br label %guard_block
+  br label %panic_block
 if.exit:                                          ; preds = %end_block
   br label %noerr_block
-guard_block:                                      ; preds = %if.then
-  %17 = load i64, ptr %error_var, align 8
-  ret i64 %17
+panic_block:                                      ; preds = %if.then
+  %17 = insertvalue %any undef, ptr %error_var, 0
+  %18 = insertvalue %any %17, i64 ptrtoint (ptr @"$ct.anyfault" to i64), 1
+  store %any %18, ptr %varargslots, align 16
+  %19 = insertvalue %"any[]" undef, ptr %varargslots, 0
+  %"$$temp" = insertvalue %"any[]" %19, i64 1, 1
+  store %"any[]" %"$$temp", ptr %indirectarg, align 8
+  call void @std.core.builtin.panicf(ptr @.panic_msg.1, i64 36, ptr @.file, i64 25, ptr @.func, i64 4, i32 8, ptr byval(%"any[]") align 8 %indirectarg)
+  unreachable
 noerr_block:                                      ; preds = %if.exit
-  ret i64 0
+  ret void
 }
\ No newline at end of file
diff --git a/test/test_suite/slices/slice_inline.c3t b/test/test_suite/slices/slice_inline.c3t
index 5e395737f..8a4ca0027 100644
--- a/test/test_suite/slices/slice_inline.c3t
+++ b/test/test_suite/slices/slice_inline.c3t
@@ -10,7 +10,7 @@ fn void Data.not_working(self) {
 fn void Data.working(self) {
     self.data[:self.data.len];
 }
-fn void! main(String[] args) {
+fn void main(String[] args) {
     Data d;
     d.not_working();
     d.working();
diff --git a/test/test_suite/statements/nextcase_const.c3t b/test/test_suite/statements/nextcase_const.c3t
index 571f7befe..1a444efb3 100644
--- a/test/test_suite/statements/nextcase_const.c3t
+++ b/test/test_suite/statements/nextcase_const.c3t
@@ -1,7 +1,7 @@
 // #target: macos-x64
 module test;
 
-fn void! main()
+fn void main()
 {
 	int a;
 	switch (a)
@@ -17,7 +17,6 @@ fn void! main()
 
 /* #expect: test.ll
 
-define i64 @test.main() #0 {
 entry:
   %a = alloca i32, align 4
   %switch = alloca i32, align 4
@@ -51,5 +50,3 @@ switch.default:                                   ; preds = %next_if4
   store i32 %sub, ptr %a, align 4
   br label %switch.exit
 switch.exit:                                      ; preds = %switch.default
-  ret i64 0
-}
\ No newline at end of file
diff --git a/test/test_suite/statements/nextcase_missing_case.c3 b/test/test_suite/statements/nextcase_missing_case.c3
index 01f3e90ee..1b2871b5b 100644
--- a/test/test_suite/statements/nextcase_missing_case.c3
+++ b/test/test_suite/statements/nextcase_missing_case.c3
@@ -1,7 +1,7 @@
 module test;
 import std::io;
 
-fn void! main()
+fn void main()
 {
 	int a;
 	switch (a)