diff --git a/src/fun/builtins.bend b/src/fun/builtins.bend
index 973f7835..4e7dd8d2 100644
--- a/src/fun/builtins.bend
+++ b/src/fun/builtins.bend
@@ -180,7 +180,7 @@ def IO/MAGIC -> (u24, u24):
 def IO/wrap(x: T) -> IO(T):
   return IO/Done(IO/MAGIC, x)
 
-def IO/bind(a: IO(A), b: A -> IO(B)) -> IO(B):
+def IO/bind(a: IO(A), b: (id -> id) -> A -> IO(B)) -> IO(B):
   match a:
     case IO/Done:
       b = undefer(b)
diff --git a/src/fun/transform/resolve_type_ctrs.rs b/src/fun/transform/resolve_type_ctrs.rs
index 2c1a57fe..9829f751 100644
--- a/src/fun/transform/resolve_type_ctrs.rs
+++ b/src/fun/transform/resolve_type_ctrs.rs
@@ -7,7 +7,7 @@ use crate::{
 };
 
 impl Ctx<'_> {
-  /// Resolves type constructors in the book and adds for alls for the free type vars.
+  /// Resolves type constructors in the book and adds for-alls for the free type vars.
   pub fn resolve_type_ctrs(&mut self) -> Result<(), Diagnostics> {
     for def in self.book.defs.values_mut() {
       let mut free_vars = Default::default();
diff --git a/src/fun/transform/type_check.rs b/src/fun/transform/type_check.rs
index 1d14b267..12f63dbc 100644
--- a/src/fun/transform/type_check.rs
+++ b/src/fun/transform/type_check.rs
@@ -374,7 +374,7 @@ fn ctr_to_kindc(ctr_nam: &Name, adt: &Adt, counter: &mut u64, book: &mut KindCBo
     typ: Box::new(KT::Set),
     bod: Box::new(typ),
   });
-  let term = KT::Ann { chk: true, bod: Box::new(term), typ: Box::new(typ) };
+  let term = KT::Ann { chk: false, bod: Box::new(term), typ: Box::new(typ) };
   book.insert(src, (ctr_nam.to_string(), term));
 }
 
@@ -425,7 +425,7 @@ fn adt_to_kindc(adt: &Adt, counter: &mut u64, book: &mut KindCBook) {
     bod: Box::new(typ),
   });
 
-  let term = KT::Ann { chk: true, bod: Box::new(term), typ: Box::new(typ) };
+  let term = KT::Ann { chk: false, bod: Box::new(term), typ: Box::new(typ) };
   book.insert(src, (adt.name.to_string(), term));
 }
 
@@ -695,7 +695,7 @@ impl Type {
       Type::Tup(els) => els.iter().fold(KT::Ref { nam: format!("kindc__tup{}", els.len()) }, |typ, el| {
         KT::App { fun: Box::new(typ), arg: Box::new(el.to_kindc(counter, src)) }
       }),
-      Type::None => KT::Ref { nam: "None".to_string() },
+      Type::None => KT::Ref { nam: "kindc__none".to_string() },
     });
     KT::Src { src, bod: Box::new(kt) }
   }
diff --git a/src/lib.rs b/src/lib.rs
index 8dfc79b3..ff34c8ec 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -103,7 +103,6 @@ pub fn desugar_book(
   ctx.book.encode_builtins();
 
   ctx.resolve_refs()?;
-  ctx.resolve_type_ctrs()?;
 
   ctx.desugar_match_defs()?;
 
@@ -128,7 +127,9 @@ pub fn desugar_book(
   // Manual match linearization
   ctx.book.linearize_match_with();
 
-  type_check_book(&mut ctx)?;
+  if opts.type_check {
+    type_check_book(&mut ctx)?;
+  }
 
   ctx.book.encode_matches(opts.adt_encoding);
 
@@ -172,6 +173,7 @@ pub fn type_check_book(ctx: &mut Ctx) -> Result<(), Diagnostics> {
   let old_book = std::mem::replace(ctx.book, ctx.book.clone());
   ctx.make_native_defs();
   ctx.book.encode_adts(AdtEncoding::Scott);
+  ctx.resolve_type_ctrs()?;
   let res = ctx.type_check();
   *ctx.book = old_book;
   res?;
@@ -365,6 +367,9 @@ pub struct CompileOpts {
   /// Enables [hvm::check_net_size].
   pub check_net_size: bool,
 
+  /// Enables [type_check_book].
+  pub type_check: bool,
+
   /// Determines the encoding of constructors and matches.
   pub adt_encoding: AdtEncoding,
 }
@@ -378,8 +383,9 @@ impl CompileOpts {
       prune: true,
       float_combinators: true,
       merge: true,
-      inline: true,
       linearize_matches: OptLevel::Enabled,
+      type_check: true,
+      inline: self.inline,
       check_net_size: self.check_net_size,
       adt_encoding: self.adt_encoding,
     }
@@ -395,6 +401,7 @@ impl CompileOpts {
       float_combinators: false,
       merge: false,
       inline: false,
+      type_check: self.type_check,
       check_net_size: self.check_net_size,
       adt_encoding: self.adt_encoding,
     }
@@ -426,6 +433,7 @@ impl Default for CompileOpts {
       merge: false,
       inline: false,
       check_net_size: false,
+      type_check: true,
       adt_encoding: AdtEncoding::NumScott,
     }
   }
diff --git a/src/main.rs b/src/main.rs
index 7acf47c3..1a2882bf 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -188,6 +188,8 @@ pub enum OptArgs {
   NoCheckNetSize,
   AdtScott,
   AdtNumScott,
+  TypeCheck,
+  NoTypeCheck,
 }
 
 fn compile_opts_from_cli(args: &Vec<OptArgs>) -> CompileOpts {
@@ -210,6 +212,8 @@ fn compile_opts_from_cli(args: &Vec<OptArgs>) -> CompileOpts {
       NoInline => opts.inline = false,
       CheckNetSize => opts.check_net_size = true,
       NoCheckNetSize => opts.check_net_size = false,
+      TypeCheck => opts.type_check = true,
+      NoTypeCheck => opts.type_check = false,
 
       LinearizeMatches => opts.linearize_matches = OptLevel::Enabled,
       LinearizeMatchesAlt => opts.linearize_matches = OptLevel::Alt,