diff --git a/cpp/src/ast.hpp b/cpp/src/ast.hpp
index ed6477b..5fb8cb7 100644
--- a/cpp/src/ast.hpp
+++ b/cpp/src/ast.hpp
@@ -20,7 +20,8 @@ struct ast
 				type == lexer::token::type::bitwise_complement ||
 				type == lexer::token::type::logical_negation ||
 				type == lexer::token::type::ref ||
-				type == lexer::token::type::deref,
+				type == lexer::token::type::deref ||
+				type == lexer::token::type::defer,
 				"internal compiler error: parsed a unary_operator via lexer token type that doesn't represent a unary operator."
 			);
 			return std::format("unary-operator \"{}\"", lexer::token_type_names[static_cast<int>(this->type)]);
diff --git a/cpp/src/codegen.cpp b/cpp/src/codegen.cpp
index b01b44a..f0b14d0 100644
--- a/cpp/src/codegen.cpp
+++ b/cpp/src/codegen.cpp
@@ -1,6 +1,7 @@
 #include "codegen.hpp"
 #include "diag.hpp"
 #include "semantic.hpp"
+#include "llvm/IR/Intrinsics.h"
 #include "llvm/IR/LLVMContext.h"
 
 #include "llvm/ADT/APInt.h"
@@ -1364,6 +1365,12 @@ namespace codegen
 			type ty = this->state.try_get_type_from_payload(ptr_expr, this->tree, this->path);
 			ret = string_literal(*this, {.val = ty.name()});
 		}
+		if(call.function_name == "__builtin_debugbreak")
+		{
+			this->assert_that(call.params.empty(), "debugbreak takes no arguments.");
+			ret.llv = builder->CreateCall(llvm::Intrinsic::getDeclaration(program.get(), llvm::Intrinsic::trap));
+			ret.ty = type::from_primitive(primitive_type::u0);
+		}
 		if(call.function_name == "__builtin_sizeof")
 		{
 			this->assert_that(call.params.size() == 1, "__builtin_typename requires one argument.");
diff --git a/cpp/src/parse.cpp b/cpp/src/parse.cpp
index fc1d358..c94524a 100644
--- a/cpp/src/parse.cpp
+++ b/cpp/src/parse.cpp
@@ -559,8 +559,11 @@ namespace parser
 				return std::nullopt;
 			}
 			std::string function_name = this->last_value();
-			this->must_match(lexer::token::type::colon);
-			this->must_match(lexer::token::type::open_paren);
+			if(!(this->match(lexer::token::type::colon) && this->match(lexer::token::type::open_paren)))
+			{
+				this->restore_index();
+				return std::nullopt;
+			}
 			std::vector<ast::variable_declaration> params = {};
 			while(!this->match(lexer::token::type::close_paren))
 			{
diff --git a/samples/scratchpad.psy b/samples/scratchpad.psy
index 429013d..2f3ca02 100644
--- a/samples/scratchpad.psy
+++ b/samples/scratchpad.psy
@@ -21,6 +21,7 @@ main : (argc : i64, argv : i8**) -> i64
 	defer default_free(shape_ptr);
 	= shape_ptr->base 'A';
 	= shape_ptr->height 19;
+	__builtin_debugbreak();
 
 	puts("the value is: ");
 	putchar(shape_ptr->get_half_perimeter());