Make fake function end unreachable so the compiler doesn't complain about missing return

rt/include/python/builtins.hpp

@@ -10,6 +10,14 @@
 #include <ostream>
 #include <string>
 
+#ifdef __cpp_lib_unreachable
+#include <utility>
+[[noreturn]] inline void TYPON_UNREACHABLE() { std::unreachable(); }
+#else
+#include <cstdlib>
+[[noreturn]] inline void TYPON_UNREACHABLE() { std::abort(); }
+#endif
+
 using namespace std::literals;
 
 // typon_len

trans/transpiler/__init__.py

@@ -408,9 +408,13 @@ class BlockVisitor(NodeVisitor):
             return result
         except UnsupportedNodeError as e:
             if isinstance(e.node, ast.Yield):
-                return chain(self.visit_func(node, CoroutineMode.FAKE), self.visit_func(node, CoroutineMode.GENERATOR))
+                return self.visit_coroutine(node)
             raise
 
+    def visit_coroutine(self, node: ast.FunctionDef) -> Iterable[str]:
+        yield from self.visit_func(node, CoroutineMode.FAKE)
+        yield from self.visit_func(node, CoroutineMode.GENERATOR)
+
     def visit_func(self, node: ast.FunctionDef, generator: CoroutineMode) -> Iterable[str]:
         templ, args, names = self.process_args(node.args)
         if templ:
@@ -478,6 +482,8 @@ class BlockVisitor(NodeVisitor):
                 elif decl.kind in (VarKind.GLOBAL, VarKind.NONLOCAL):  # `global` and `nonlocal` just get hoisted as-is.
                     inner_scope.vars[var] = decl
             yield from child_code  # Yeet back the child node code.
+        if generator == CoroutineMode.FAKE:
+            yield "TYPON_UNREACHABLE();"  # So the compiler doesn't complain about missing return statements.
         yield "}"
 
     def visit_lvalue(self, lvalue: ast.expr, val: Optional[ast.AST] = None) -> Iterable[str]: