diff --git a/shard.yml b/shard.yml
index c537668..6d8f8df 100644
--- a/shard.yml
+++ b/shard.yml
@@ -1,6 +1,6 @@
 name: fancyline
 description: Readline-esque library with fancy features
-version: 0.3.1
+version: 0.3.2
 
 authors:
   - Stefan Merettig <stefan-merettig@nuriaproject.org>
@@ -10,6 +10,6 @@ dependencies:
     github: Papierkorb/cute
     version: ">= 0.3.1"
 
-crystal: 0.32.1
+crystal: 0.34.0
 
 license: MPL-2
diff --git a/src/fancyline.cr b/src/fancyline.cr
index 914aaf4..e42ff49 100644
--- a/src/fancyline.cr
+++ b/src/fancyline.cr
@@ -184,7 +184,7 @@ class Fancyline
   # Copied from IO::FileDescriptor, as this method is sadly `private`.
   protected def preserving_tc_mode(fd)
     if LibC.tcgetattr(fd, out mode) != 0
-      raise Errno.new("Failed to enable raw mode on output")
+      raise RuntimeError.from_errno("Failed to enable raw mode on output")
     end
 
     before = mode
diff --git a/src/fancyline/key.cr b/src/fancyline/key.cr
index 89bbb47..7f9e290 100644
--- a/src/fancyline/key.cr
+++ b/src/fancyline/key.cr
@@ -4,11 +4,11 @@ class Fancyline
   module Key
     enum Control
       Backspace = 127
-      Return = 13 # Same as Ctrl-M
+      Return    =  13 # Same as Ctrl-M
       AltReturn
-      Tab = 9
+      Tab       = 9
       ShiftTab
-      Escape = 27
+      Escape    = 27
 
       CtrlA = 1
       CtrlB = 2
@@ -156,6 +156,8 @@ class Fancyline
         when 81 then Control::F2
         when 82 then Control::F3
         when 83 then Control::F4
+        else
+          nil
         end
       when 91 # Movement and F-keys
         case yield.try(&.ord)
@@ -244,6 +246,8 @@ class Fancyline
         when 70 then Control::End
         when 72 then Control::Home
         when 90 then Control::ShiftTab
+        else
+          nil
         end
       # Alt-Letter keys
       when 97 then Control::AltA
@@ -272,6 +276,8 @@ class Fancyline
       when 120 then Control::AltX
       when 121 then Control::AltY
       when 122 then Control::AltZ
+      else
+        nil
       end
     end
   end