diff --git a/src/testdir/test_vim9_script.vim b/src/testdir/test_vim9_script.vim
index fd1dbc8..4284aad 100644
--- a/src/testdir/test_vim9_script.vim
+++ b/src/testdir/test_vim9_script.vim
@@ -14,6 +14,8 @@
 let g:existing = 'yes'
 let g:inc_counter = 1
 let $SOME_ENV_VAR = 'some'
+let g:alist = [7]
+let g:astring = 'text'
 
 def Test_assignment()
   let bool1: bool = true
@@ -95,7 +97,12 @@
   assert_equal(2, &ts)
   call CheckDefFailure(['&notex += 3'], 'E113:')
   call CheckDefFailure(['&ts ..= "xxx"'], 'E1019:')
+  call CheckDefFailure(['&ts = [7]'], 'E1013:')
+  call CheckDefExecFailure(['&ts = g:alist'], 'E1029: Expected number but got list')
+  call CheckDefFailure(['&ts = "xx"'], 'E1013:')
+  call CheckDefExecFailure(['&ts = g:astring'], 'E1029: Expected number but got string')
   call CheckDefFailure(['&path += 3'], 'E1013:')
+  call CheckDefExecFailure(['&bs = "asdf"'], 'E474:')
   # test freeing ISN_STOREOPT
   call CheckDefFailure(['&ts = 3', 'let asdf'], 'E1022:')
   &ts = 8
diff --git a/src/version.c b/src/version.c
index 94db9b8..b361ded 100644
--- a/src/version.c
+++ b/src/version.c
@@ -747,6 +747,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    764,
+/**/
     763,
 /**/
     762,
diff --git a/src/vim9compile.c b/src/vim9compile.c
index 4b294df..416198a 100644
--- a/src/vim9compile.c
+++ b/src/vim9compile.c
@@ -3490,7 +3490,7 @@
 	    type_T	**typep;
 
 	    // list index: list[123]
-	    // list member: dict[key]
+	    // dict member: dict[key]
 	    // TODO: blob index
 	    // TODO: more arguments
 	    // TODO: recognize list or dict at runtime
@@ -4999,8 +4999,8 @@
 			goto theend;
 		}
 	    }
-	    else if (*p != '=' && check_type(member_type, stacktype, TRUE)
-								       == FAIL)
+	    else if (*p != '=' && need_type(stacktype, member_type, -1,
+								 cctx) == FAIL)
 		goto theend;
 	}
     }
diff --git a/src/vim9execute.c b/src/vim9execute.c
index f50f8c6..398c94c 100644
--- a/src/vim9execute.c
+++ b/src/vim9execute.c
@@ -1164,13 +1164,9 @@
 			if (s == NULL)
 			    s = (char_u *)"";
 		    }
-		    else if (tv->v_type == VAR_NUMBER)
-			n = tv->vval.v_number;
 		    else
-		    {
-			emsg(_("E1051: Expected string or number"));
-			goto failed;
-		    }
+			// must be VAR_NUMBER, CHECKTYPE makes sure
+			n = tv->vval.v_number;
 		    msg = set_option_value(iptr->isn_arg.storeopt.so_name,
 					n, s, iptr->isn_arg.storeopt.so_flags);
 		    if (msg != NULL)