diff --git a/src/bin/fish_key_reader.rs b/src/bin/fish_key_reader.rs
index b401621b1..7412b27fc 100644
--- a/src/bin/fish_key_reader.rs
+++ b/src/bin/fish_key_reader.rs
@@ -23,7 +23,7 @@
         terminal_protocol_hacks, terminal_protocols_enable_ifn, CharEvent, InputEventQueue,
         InputEventQueuer,
     },
-    key::{self, char_to_symbol, Key},
+    key::{char_to_symbol, Key},
     panic::panic_handler,
     print_help::print_help,
     printf,
@@ -101,9 +101,6 @@ fn process_input(continuous_mode: bool, verbose: bool) -> i32 {
             continue;
         };
         let c = kevt.key.codepoint;
-        if c == key::Invalid {
-            continue;
-        }
         if verbose {
             printf!("# decoded from: ");
             for byte in kevt.seq.chars() {
diff --git a/src/input_common.rs b/src/input_common.rs
index 704bfbb72..eaa253dfc 100644
--- a/src/input_common.rs
+++ b/src/input_common.rs
@@ -691,6 +691,7 @@ fn try_readch(&mut self, blocking: bool) -> Option<CharEvent> {
                     if key == Some(Key::from_raw(key::Invalid)) {
                         continue;
                     }
+                    assert!(key.map_or(true, |key| key.codepoint != key::Invalid));
                     let mut consumed = 0;
                     let mut state = zero_mbstate();
                     let mut i = 0;
@@ -767,10 +768,13 @@ fn parse_escape_sequence(
             return Some(
                 match self.parse_escape_sequence(buffer, have_escape_prefix) {
                     Some(mut nested_sequence) => {
+                        if nested_sequence == invalid {
+                            return Some(Key::from_raw(key::Escape));
+                        }
                         nested_sequence.modifiers.alt = true;
                         nested_sequence
                     }
-                    None => invalid,
+                    _ => invalid,
                 },
             );
         }
diff --git a/src/key.rs b/src/key.rs
index 7b8346ff5..59a8ce56e 100644
--- a/src/key.rs
+++ b/src/key.rs
@@ -23,7 +23,7 @@
 pub(crate) const Insert: char = '\u{F50c}';
 pub(crate) const Tab: char = '\u{F50d}';
 pub(crate) const Space: char = '\u{F50e}';
-pub const Invalid: char = '\u{F50f}';
+pub(crate) const Invalid: char = '\u{F50f}';
 pub(crate) fn function_key(n: u32) -> char {
     assert!((1..=12).contains(&n));
     char::from_u32(u32::from(Invalid) + n).unwrap()