Fix kill-a-word kill-inner-word bounds checks if at end of command line

These commands are meant to be used in Vi mode when the cursor is on
a valid character, so there's not much reason to try to make them do
something when the cursor is past-end.  Do nothing, like we already
do for the empty commandline.

Reported in #12430

src/reader/reader.rs

@@ -2320,11 +2320,11 @@ fn move_word(
 
     fn delete_a_word(&mut self, elt: EditableLineTag, style: MoveWordStyle, newv: bool) {
         let el = self.edit_line(elt);
-        if el.is_empty() {
+        let pos = el.position();
+        if pos == el.len() {
             return;
         }
         let text_slice = el.text().as_char_slice();
-        let pos = el.position();
         let on_blank = is_blank(text_slice[pos]);
 
         if on_blank {
@@ -2396,10 +2396,10 @@ fn delete_a_word(&mut self, elt: EditableLineTag, style: MoveWordStyle, newv: bo
     fn delete_inner_word(&mut self, elt: EditableLineTag, style: MoveWordStyle, newv: bool) {
         let el = self.edit_line(elt);
         let len = el.len();
-        if len == 0 {
+        let pos = el.position();
+        if pos == len {
             return;
         }
-        let pos = el.position();
         let text_slice = el.text().as_char_slice();
         if is_blank(text_slice[pos]) {
             // Cursor is on whitespace: delete whitespace only

tests/pexpects/bind.py

@@ -666,6 +666,22 @@ expect_prompt()
 send("\x07")  # ctrl-g
 send("\x1b[27u")  # escape, to close pager
 
+sendline("bind ctrl-g kill-inner-word")
+expect_prompt()
+send("echo foo-bar")
+send("\x07")  # ctrl-g
+sendline("baz")
+expect_str("foo-barbaz")
+expect_prompt()
+
+sendline("bind ctrl-g kill-a-word")
+expect_prompt()
+send("echo foo-bar")
+send("\x07")  # ctrl-g
+sendline("qux")
+expect_str("foo-barqux")
+expect_prompt()
+
 # Check that the builtin version of `exit` works
 # (for obvious reasons this MUST BE LAST)
 sendline("function myexit; echo exit; exit; end; bind ctrl-z myexit")