patch 9.0.2076: Vim9: No support for type aliases Commit: https://github.com/vim/vim/commit/ec3cebbd2b6b7583d2f683f5e66345163ec122aa Author: Yegappan Lakshmanan <yegappan@yahoo.com> Date: Fri Oct 27 19:35:26 2023 +0200 patch 9.0.2076: Vim9: No support for type aliases Problem: Vim9: No support for type aliases Solution: Implement :type command A type definition is giving a name to a type specification. This also known type alias. :type ListOfStrings = list<string> The type alias can be used wherever a built-in type can be used. The type alias name must start with an upper case character. closes: #13407 Signed-off-by: Christian Brabandt <cb@256bit.org> Signed-off-by: Yegappan Lakshmanan <yegappan@yahoo.com>

--- a/src/vim9execute.c
+++ b/src/vim9execute.c
@@ -3807,6 +3807,13 @@ exec_instructions(ectx_T *ectx)
 	    case ISN_STORE:
 		--ectx->ec_stack.ga_len;
 		tv = STACK_TV_VAR(iptr->isn_arg.number);
+		if (STACK_TV_BOT(0)->v_type == VAR_TYPEALIAS)
+		{
+		    semsg(_(e_using_typealias_as_variable),
+				STACK_TV_BOT(0)->vval.v_typealias->ta_name);
+		    clear_tv(STACK_TV_BOT(0));
+		    goto on_error;
+		}
 		clear_tv(tv);
 		*tv = *STACK_TV_BOT(0);
 		break;
@@ -7517,6 +7524,7 @@ tv2bool(typval_T *tv)
 	case VAR_INSTR:
 	case VAR_CLASS:
 	case VAR_OBJECT:
+	case VAR_TYPEALIAS:
 	    break;
     }
     return FALSE;