diff --git a/src/ast.ts b/src/ast.ts
index 92f636e..ed9b352 100644
--- a/src/ast.ts
+++ b/src/ast.ts
@@ -115,7 +115,7 @@ export type ExprBreak = {
    * The break target block.
    * May be any control flow block, labelled from inside out.
    */
-  target?: number,
+  target?: number;
 };
 
 export type ExprStructLiteral = {
@@ -261,6 +261,7 @@ export const BUILTINS = [
   "print",
   "String",
   "Int",
+  "I32",
   "Bool",
   "true",
   "false",
@@ -282,7 +283,10 @@ export type TyString = {
 
 export type TyInt = {
   kind: "int";
-  signed: boolean;
+};
+
+export type TyI32 = {
+  kind: "i32";
 };
 
 export type TyBool = {
@@ -328,6 +332,7 @@ export type TyNever = {
 export type Ty =
   | TyString
   | TyInt
+  | TyI32
   | TyBool
   | TyList
   | TyTuple
@@ -343,7 +348,8 @@ export function tyIsUnit(ty: Ty): ty is TyUnit {
 export const TY_UNIT: Ty = { kind: "tuple", elems: [] };
 export const TY_STRING: Ty = { kind: "string" };
 export const TY_BOOL: Ty = { kind: "bool" };
-export const TY_INT: Ty = { kind: "int", signed: false };
+export const TY_INT: Ty = { kind: "int" };
+export const TY_I32: Ty = { kind: "i32" };
 export const TY_NEVER: Ty = { kind: "never" };
 
 export type TypeckResults = {
diff --git a/src/index.ts b/src/index.ts
index 25b2923..7c6f023 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -10,11 +10,15 @@ import fs from "fs";
 import { exec } from "child_process";
 
 const input = `
+// import "wasi_snapshot_preview1" "fd_write"(a: I32, b: I32, c: I32, d: I32): I32;
+
 function main() = (
   loop (no(break););
   uwu(10);
 );
 
+function meow(a: I32): I32 = a;
+
 function no(a: !): String = a;
 
 function uwu(a: Int) = if a != 0 then (
diff --git a/src/lower.ts b/src/lower.ts
index b32eb52..0d9b0ee 100644
--- a/src/lower.ts
+++ b/src/lower.ts
@@ -524,6 +524,8 @@ function computeAbi(ty: TyFn): FnAbi {
         todo("fn abi");
       case "int":
         return ["i64"];
+      case "i32":
+        return ["i32"];
       case "bool":
         return ["i32"];
       case "list":
@@ -572,6 +574,8 @@ function wasmTypeForBody(ty: Ty): wasm.ValType[] {
       return STRING_TYPES;
     case "int":
       return ["i64"];
+    case "i32":
+      return ["i32"];
     case "bool":
       return ["i32"];
     case "list":
diff --git a/src/printer.ts b/src/printer.ts
index 4b28fb2..4ecd65c 100644
--- a/src/printer.ts
+++ b/src/printer.ts
@@ -178,6 +178,9 @@ export function printTy(ty: Ty): string {
     case "int": {
       return "Int";
     }
+    case "i32": {
+      return "I32";
+    }
     case "bool": {
       return "Bool";
     }
diff --git a/src/typeck.ts b/src/typeck.ts
index e0eebf1..f15a558 100644
--- a/src/typeck.ts
+++ b/src/typeck.ts
@@ -15,6 +15,7 @@ import {
   Resolution,
   Ty,
   TY_BOOL,
+  TY_I32,
   TY_INT,
   TY_NEVER,
   TY_STRING,
@@ -34,6 +35,9 @@ function builtinAsTy(name: string, span: Span): Ty {
     case "Int": {
       return TY_INT;
     }
+    case "I32": {
+      return TY_I32;
+    }
     case "Bool": {
       return TY_BOOL;
     }
@@ -355,6 +359,10 @@ export class InferContext {
         if (rhs.kind === "int") return;
         break;
       }
+      case "i32": {
+        if (rhs.kind === "i32") return;
+        break;
+      }
       case "bool": {
         if (rhs.kind === "bool") return;
         break;