diff --git a/reid/src/mir/mod.rs b/reid/src/mir/mod.rs
index 7024878..194f176 100644
--- a/reid/src/mir/mod.rs
+++ b/reid/src/mir/mod.rs
@@ -67,6 +67,8 @@ pub enum VagueType {
     Unknown,
     #[error("Number")]
     Number,
+    #[error("Hinted({0})")]
+    Hinted(usize),
 }
 
 impl TypeKind {
@@ -158,6 +160,14 @@ impl Literal {
     }
 }
 
+impl VagueLiteral {
+    pub fn as_type(self: &VagueLiteral) -> VagueType {
+        match self {
+            VagueLiteral::Number(_) => VagueType::Number,
+        }
+    }
+}
+
 #[derive(Debug, Clone, Copy)]
 pub enum BinaryOperator {
     Add,
diff --git a/reid/src/mir/scopehints.rs b/reid/src/mir/scopehints.rs
index a8e1773..12eea26 100644
--- a/reid/src/mir/scopehints.rs
+++ b/reid/src/mir/scopehints.rs
@@ -1,46 +1,77 @@
-use std::{cell::RefCell, collections::HashMap};
+use std::{cell::RefCell, collections::HashMap, fmt::Error, rc::Rc};
 
 use super::{
     typecheck::{Collapsable, ErrorKind},
-    TypeKind,
+    BinaryOperator, Literal, TypeKind, VagueLiteral, VagueType,
 };
 
-#[derive(Debug, Clone)]
-pub struct ScopeHint<'scope>(usize, &'scope ScopeHints<'scope>);
+#[derive(Clone)]
+pub struct ScopeHint<'scope>(TypeIdRef, &'scope ScopeHints<'scope>);
 
 impl<'scope> ScopeHint<'scope> {
-    pub fn resolve(&self) -> TypeRef {
-        let mut scope = self.1;
-        while !scope.type_hints.borrow().contains_key(&self.0) {
-            scope = scope.outer.as_ref().unwrap();
-        }
-        let ty = scope.type_hints.borrow().get(&self.0).unwrap().clone();
-        match ty.known() {
-            Ok(narrow) => TypeRef::Literal(narrow),
-            Err(_) => TypeRef::Hint(self.clone()),
+    pub unsafe fn raw_type(&self) -> TypeKind {
+        if let Some(ty) = self.1.types.hints.borrow().get(*self.0.borrow()) {
+            *ty
+        } else {
+            panic!("TODO")
         }
     }
 
-    pub fn narrow(&self, ty_ref: &TypeRef) -> Result<ScopeHint, ErrorKind> {
+    pub fn narrow(&mut self, ty_ref: &TypeRef) -> Result<ScopeHint<'scope>, ErrorKind> {
         match ty_ref {
             TypeRef::Hint(other) => self.1.combine_vars(self, other),
             TypeRef::Literal(ty) => self.1.narrow_to_type(self, ty),
         }
     }
+
+    pub fn as_type(&self) -> TypeKind {
+        TypeKind::Vague(super::VagueType::Hinted(*self.0.borrow()))
+    }
 }
 
+impl<'scope> std::fmt::Debug for ScopeHint<'scope> {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        f.debug_tuple("Hint")
+            .field(&self.0)
+            .field(unsafe { &self.raw_type() })
+            .finish()
+    }
+}
+
+type TypeIdRef = Rc<RefCell<usize>>;
+
 #[derive(Debug, Default)]
+pub struct TypeHints {
+    /// Simple list of types that variables can refrence
+    hints: RefCell<Vec<TypeKind>>,
+    types: RefCell<Vec<TypeIdRef>>,
+}
+
+impl TypeHints {
+    pub fn new(&self, ty: TypeKind) -> TypeIdRef {
+        let idx = self.hints.borrow().len();
+        let typecell = Rc::new(RefCell::new(idx));
+        self.types.borrow_mut().push(typecell.clone());
+        self.hints.borrow_mut().push(ty);
+        typecell
+    }
+}
+
+#[derive(Debug)]
 pub struct ScopeHints<'outer> {
+    types: &'outer TypeHints,
     outer: Option<&'outer ScopeHints<'outer>>,
     /// Mapping of what types variables point to
-    variables: RefCell<HashMap<String, (bool, usize)>>,
-    /// Simple list of types that variables can refrence
-    type_hints: RefCell<HashMap<usize, TypeKind>>,
+    variables: RefCell<HashMap<String, (bool, TypeIdRef)>>,
 }
 
 impl<'outer> ScopeHints<'outer> {
-    fn get_idx(&self) -> usize {
-        self.type_hints.borrow().len() + self.outer.as_ref().map(|o| o.get_idx()).unwrap_or(0)
+    pub fn from(types: &'outer TypeHints) -> ScopeHints<'outer> {
+        ScopeHints {
+            types,
+            outer: Default::default(),
+            variables: Default::default(),
+        }
     }
 
     pub fn new_var(
@@ -52,21 +83,29 @@ impl<'outer> ScopeHints<'outer> {
         if self.variables.borrow().contains_key(&name) {
             return Err(ErrorKind::VariableAlreadyDefined(name));
         }
-        let idx = self.get_idx();
-        self.variables.borrow_mut().insert(name, (mutable, idx));
-        self.type_hints.borrow_mut().insert(idx, initial_ty);
+        let idx = self.types.new(initial_ty);
+        self.variables
+            .borrow_mut()
+            .insert(name, (mutable, idx.clone()));
         Ok(ScopeHint(idx, self))
     }
 
+    fn new_vague(&'outer self, vague: &VagueType) -> ScopeHint<'outer> {
+        let idx = self.types.new(TypeKind::Vague(*vague));
+        ScopeHint(idx, self)
+    }
+
     fn narrow_to_type(
         &'outer self,
         hint: &ScopeHint,
         ty: &TypeKind,
     ) -> Result<ScopeHint<'outer>, ErrorKind> {
-        let mut hints = self.type_hints.borrow_mut();
-        let existing = hints.get_mut(&hint.0).unwrap();
-        *existing = existing.collapse_into(&ty)?;
-        Ok(ScopeHint(hint.0, self))
+        unsafe {
+            let mut hints = self.types.hints.borrow_mut();
+            let existing = hints.get_unchecked_mut(*hint.0.borrow());
+            *existing = existing.collapse_into(&ty)?;
+            Ok(ScopeHint(hint.0.clone(), self))
+        }
     }
 
     fn combine_vars(
@@ -74,21 +113,28 @@ impl<'outer> ScopeHints<'outer> {
         hint1: &ScopeHint,
         hint2: &ScopeHint,
     ) -> Result<ScopeHint<'outer>, ErrorKind> {
-        let ty = self.type_hints.borrow().get(&hint2.0).unwrap().clone();
-        self.narrow_to_type(&hint1, &ty)?;
-        for (_, (_, idx)) in self.variables.borrow_mut().iter_mut() {
-            if *idx == hint2.0 {
-                *idx = hint1.0;
+        unsafe {
+            let ty = self
+                .types
+                .hints
+                .borrow()
+                .get_unchecked(*hint2.0.borrow())
+                .clone();
+            self.narrow_to_type(&hint1, &ty)?;
+            for idx in self.types.types.borrow_mut().iter_mut() {
+                if *idx == hint2.0 {
+                    *idx.borrow_mut() = *hint1.0.borrow();
+                }
             }
+            Ok(ScopeHint(hint1.0.clone(), self))
         }
-        Ok(ScopeHint(hint1.0, self))
     }
 
     pub fn inner(&'outer self) -> ScopeHints<'outer> {
         ScopeHints {
+            types: self.types,
             outer: Some(self),
             variables: Default::default(),
-            type_hints: Default::default(),
         }
     }
 
@@ -96,20 +142,35 @@ impl<'outer> ScopeHints<'outer> {
         self.variables
             .borrow()
             .get(name)
-            .map(|(mutable, idx)| (*mutable, ScopeHint(*idx, self)))
+            .map(|(mutable, idx)| (*mutable, ScopeHint(idx.clone(), self)))
+            .or(self.outer.map(|o| o.find_hint(name)).flatten())
+    }
+
+    pub fn binop(
+        &'outer self,
+        op: &BinaryOperator,
+        lhs: &mut TypeRef<'outer>,
+        rhs: &mut TypeRef<'outer>,
+    ) -> Result<TypeRef<'outer>, ErrorKind> {
+        let ty = lhs.narrow(rhs)?;
+        Ok(match op {
+            BinaryOperator::Add => ty,
+            BinaryOperator::Minus => ty,
+            BinaryOperator::Mult => ty,
+            BinaryOperator::And => TypeRef::Literal(TypeKind::Bool),
+            BinaryOperator::Cmp(_) => TypeRef::Literal(TypeKind::Bool),
+        })
     }
 }
 
+#[derive(Debug)]
 pub enum TypeRef<'scope> {
     Hint(ScopeHint<'scope>),
     Literal(TypeKind),
 }
 
 impl<'scope> TypeRef<'scope> {
-    pub fn narrow(
-        &'scope self,
-        other: &'scope TypeRef<'scope>,
-    ) -> Result<TypeRef<'scope>, ErrorKind> {
+    pub fn narrow(&mut self, other: &mut TypeRef<'scope>) -> Result<TypeRef<'scope>, ErrorKind> {
         match (self, other) {
             (TypeRef::Hint(hint), unk) | (unk, TypeRef::Hint(hint)) => {
                 Ok(TypeRef::Hint(hint.narrow(unk)?))
@@ -119,4 +180,27 @@ impl<'scope> TypeRef<'scope> {
             }
         }
     }
+
+    pub fn from_type(hints: &'scope ScopeHints<'scope>, ty: TypeKind) -> TypeRef<'scope> {
+        match &ty.known() {
+            Ok(ty) => TypeRef::Literal(*ty),
+            Err(vague) => match &vague {
+                super::VagueType::Hinted(idx) => TypeRef::Hint(ScopeHint(
+                    unsafe { hints.types.types.borrow().get_unchecked(*idx).clone() },
+                    hints,
+                )),
+                _ => TypeRef::Hint(hints.new_vague(vague)),
+            },
+        }
+    }
+
+    pub fn from_literal(
+        hints: &'scope ScopeHints<'scope>,
+        lit: Literal,
+    ) -> Result<TypeRef<'scope>, ErrorKind> {
+        Ok(match lit {
+            Literal::Vague(vague) => TypeRef::Hint(hints.new_vague(&vague.as_type())),
+            _ => TypeRef::Literal(lit.as_type()),
+        })
+    }
 }
diff --git a/reid/src/mir/typecheck.rs b/reid/src/mir/typecheck.rs
index 3d4dfc6..6cdb424 100644
--- a/reid/src/mir/typecheck.rs
+++ b/reid/src/mir/typecheck.rs
@@ -1,6 +1,9 @@
 //! This module contains code relevant to doing a type checking pass on the MIR.
 //! During typechecking relevant types are also coerced if possible.
-use std::{cell::RefCell, collections::HashMap, convert::Infallible, iter, marker::PhantomData};
+use std::{
+    cell::RefCell, collections::HashMap, convert::Infallible, iter, marker::PhantomData,
+    thread::scope,
+};
 
 use crate::{mir::*, util::try_all};
 use TypeKind::*;
@@ -8,8 +11,8 @@ use VagueType::*;
 
 use super::{
     pass::{Pass, PassState, ScopeFunction, ScopeVariable, Storage},
-    scopehints::ScopeHints,
-    types::ReturnType,
+    scopehints::{ScopeHints, TypeHints, TypeRef},
+    types::{pick_return, ReturnType},
 };
 
 #[derive(thiserror::Error, Debug, Clone)]
@@ -77,7 +80,16 @@ impl FunctionDefinition {
         let inferred = match &mut self.kind {
             FunctionDefinitionKind::Local(block, _) => {
                 state.scope.return_type_hint = Some(self.return_type);
-                block.typecheck(state, &ScopeHints::default(), Some(return_type))
+
+                let types = TypeHints::default();
+                let hints = ScopeHints::from(&types);
+                if let Ok(_) = block.infer_hints(state, &hints) {
+                    dbg!(&block, &hints);
+                    // block.typecheck(state, &hints, Some(return_type))
+                    Ok(Vague(Unknown))
+                } else {
+                    Ok(Vague(Unknown))
+                }
             }
             FunctionDefinitionKind::Extern => Ok(Vague(Unknown)),
         };
@@ -92,6 +104,69 @@ impl FunctionDefinition {
 }
 
 impl Block {
+    fn infer_hints<'s>(
+        &mut self,
+        state: &mut PassState<ErrorKind>,
+        outer_hints: &'s ScopeHints,
+    ) -> Result<(ReturnKind, TypeRef<'s>), ErrorKind> {
+        let mut state = state.inner();
+        let inner_hints = outer_hints.inner();
+
+        for statement in &mut self.statements {
+            match &mut statement.0 {
+                StmtKind::Let(var, mutable, expr) => {
+                    let mut var_ref =
+                        state.ok(inner_hints.new_var(var.1.clone(), *mutable, var.0), var.2);
+                    if let Some(var_ref) = &var_ref {
+                        var.0 = var_ref.as_type();
+                    }
+                    let inferred = expr.infer_hints(&mut state, &inner_hints);
+                    let mut expr_ty_ref = state.ok(inferred, expr.1);
+                    if let (Some(var_ref), Some(expr_ty_ref)) =
+                        (var_ref.as_mut(), expr_ty_ref.as_mut())
+                    {
+                        state.ok(var_ref.narrow(&expr_ty_ref), var.2 + expr.1);
+                    }
+                }
+                StmtKind::Set(var, expr) => {
+                    let var_ref = inner_hints.find_hint(&var.1);
+                    dbg!(&var_ref);
+                    if let Some((_, var_ref)) = &var_ref {
+                        var.0 = var_ref.as_type()
+                    }
+                    let inferred = expr.infer_hints(&mut state, &inner_hints);
+                    let expr_ty_ref = state.ok(inferred, expr.1);
+                    if let (Some((_, mut var_ref)), Some(expr_ty_ref)) = (var_ref, expr_ty_ref) {
+                        state.ok(var_ref.narrow(&expr_ty_ref), var.2 + expr.1);
+                    }
+                }
+                StmtKind::Import(_) => todo!(),
+                StmtKind::Expression(expr) => {
+                    let expr_res = expr.infer_hints(&mut state, &inner_hints);
+                    state.ok(expr_res, expr.1);
+                }
+            };
+        }
+
+        if let Some(ret_expr) = &mut self.return_expression {
+            let ret_res = ret_expr.1.infer_hints(&mut state, &inner_hints);
+            state.ok(ret_res, ret_expr.1 .1);
+        }
+
+        let (kind, ty) = self.return_type().ok().unwrap_or((ReturnKind::Soft, Void));
+        let mut ret_type_ref = TypeRef::from_type(&outer_hints, ty);
+
+        if kind == ReturnKind::Hard {
+            if let Some(hint) = state.scope.return_type_hint {
+                state.ok(
+                    ret_type_ref.narrow(&mut TypeRef::from_type(outer_hints, hint)),
+                    self.meta,
+                );
+            }
+        }
+        Ok((kind, ret_type_ref))
+    }
+
     fn typecheck(
         &mut self,
         state: &mut PassState<ErrorKind>,
@@ -230,6 +305,92 @@ impl Block {
 }
 
 impl Expression {
+    fn infer_hints<'s>(
+        &mut self,
+        state: &mut PassState<ErrorKind>,
+        hints: &'s ScopeHints<'s>,
+    ) -> Result<TypeRef<'s>, ErrorKind> {
+        match &mut self.0 {
+            ExprKind::Variable(var) => {
+                let hint = hints
+                    .find_hint(&var.1)
+                    .map(|(_, hint)| hint)
+                    .ok_or(ErrorKind::VariableNotDefined(var.1.clone()));
+                if let Ok(hint) = &hint {
+                    var.0 = hint.as_type()
+                }
+                Ok(TypeRef::Hint(hint?))
+            }
+            ExprKind::Literal(literal) => TypeRef::from_literal(hints, *literal),
+            ExprKind::BinOp(op, lhs, rhs) => {
+                let mut lhs_ref = lhs.infer_hints(state, hints)?;
+                let mut rhs_ref = rhs.infer_hints(state, hints)?;
+                hints.binop(op, &mut lhs_ref, &mut rhs_ref)
+            }
+            ExprKind::FunctionCall(function_call) => {
+                let fn_call = state
+                    .scope
+                    .function_returns
+                    .get(&function_call.name)
+                    .ok_or(ErrorKind::FunctionNotDefined(function_call.name.clone()))?
+                    .clone();
+
+                let true_params_iter = fn_call.params.iter().chain(iter::repeat(&Vague(Unknown)));
+
+                for (param_expr, param_t) in
+                    function_call.parameters.iter_mut().zip(true_params_iter)
+                {
+                    let expr_res = param_expr.infer_hints(state, hints);
+                    if let Some(mut param_ref) = state.ok(expr_res, param_expr.1) {
+                        state.ok(
+                            param_ref.narrow(&mut TypeRef::from_type(hints, *param_t)),
+                            param_expr.1,
+                        );
+                    }
+                }
+
+                Ok(TypeRef::from_type(hints, fn_call.ret))
+            }
+            ExprKind::If(IfExpression(cond, lhs, rhs)) => {
+                let cond_res = cond.infer_hints(state, hints);
+                let cond_hints = state.ok(cond_res, cond.1);
+
+                if let Some(mut cond_hints) = cond_hints {
+                    state.ok(cond_hints.narrow(&mut TypeRef::Literal(Bool)), cond.1);
+                }
+
+                let lhs_res = lhs.infer_hints(state, hints);
+                let lhs_hints = state.ok(lhs_res, cond.1);
+
+                if let Some(rhs) = rhs {
+                    let rhs_res = rhs.infer_hints(state, hints);
+                    let rhs_hints = state.ok(rhs_res, cond.1);
+
+                    if let (Some(mut lhs_hints), Some(mut rhs_hints)) = (lhs_hints, rhs_hints) {
+                        state.ok(lhs_hints.1.narrow(&mut rhs_hints.1), self.1);
+                        Ok(pick_return(lhs_hints, rhs_hints).1)
+                    } else {
+                        // Failed to retrieve types from either
+                        Ok(TypeRef::from_type(hints, Vague(Unknown)))
+                    }
+                } else {
+                    if let Some((_, type_ref)) = lhs_hints {
+                        Ok(type_ref)
+                    } else {
+                        Ok(TypeRef::from_type(hints, Vague(Unknown)))
+                    }
+                }
+            }
+            ExprKind::Block(block) => {
+                let block_ref = block.infer_hints(state, hints)?;
+                match block_ref.0 {
+                    ReturnKind::Hard => Ok(TypeRef::from_type(hints, Void)),
+                    ReturnKind::Soft => Ok(block_ref.1),
+                }
+            }
+        }
+    }
+
     fn typecheck(
         &mut self,
         state: &mut PassState<ErrorKind>,
@@ -415,6 +576,7 @@ impl TypeKind {
             Vague(vague_type) => match vague_type {
                 Unknown => Err(ErrorKind::TypeIsVague(*vague_type)),
                 Number => Ok(TypeKind::I32),
+                Hinted(_) => panic!("Hinted default!"),
             },
             _ => Ok(*self),
         }
diff --git a/reid/src/mir/types.rs b/reid/src/mir/types.rs
index 369ec7f..448908b 100644
--- a/reid/src/mir/types.rs
+++ b/reid/src/mir/types.rs
@@ -1,11 +1,14 @@
+use crate::mir::typecheck::Collapsable;
+
 use super::*;
 
 #[derive(Debug, Clone)]
 pub enum ReturnTypeOther {
-    Import(TokenRange),
-    Let(TokenRange),
-    EmptyBlock(TokenRange),
-    NoBlockReturn(TokenRange),
+    Import(Metadata),
+    Let(Metadata),
+    Set(Metadata),
+    EmptyBlock(Metadata),
+    NoBlockReturn(Metadata),
 }
 
 pub trait ReturnType {
@@ -14,9 +17,25 @@ pub trait ReturnType {
 
 impl ReturnType for Block {
     fn return_type(&self) -> Result<(ReturnKind, TypeKind), ReturnTypeOther> {
+        let mut early_return = None;
+
+        for statement in &self.statements {
+            let ret = statement.return_type();
+            if let Ok((ReturnKind::Hard, _)) = ret {
+                early_return = early_return.or(ret.ok());
+            }
+        }
+
+        // TODO should actually probably prune all instructions after this one
+        // as to not cause problems in codegen later (when unable to delete the
+        // block)
+        if let Some((ReturnKind::Hard, ret_ty)) = early_return {
+            return Ok((ReturnKind::Hard, ret_ty));
+        }
+
         self.return_expression
             .as_ref()
-            .ok_or(ReturnTypeOther::NoBlockReturn(self.meta.range))
+            .ok_or(ReturnTypeOther::NoBlockReturn(self.meta))
             .and_then(|(kind, stmt)| Ok((*kind, stmt.return_type()?.1)))
     }
 }
@@ -25,10 +44,16 @@ impl ReturnType for Statement {
     fn return_type(&self) -> Result<(ReturnKind, TypeKind), ReturnTypeOther> {
         use StmtKind::*;
         match &self.0 {
-            Expression(e) => e.return_type(),
-            Set(_, _) => todo!(),
-            Import(_) => Err(ReturnTypeOther::Import(self.1.range)),
-            Let(_, _, _) => Err(ReturnTypeOther::Let(self.1.range)),
+            Let(var, _, expr) => if_hard(
+                expr.return_type()?,
+                Err(ReturnTypeOther::Let(var.2 + expr.1)),
+            ),
+            Set(var, expr) => if_hard(
+                expr.return_type()?,
+                Err(ReturnTypeOther::Set(var.2 + expr.1)),
+            ),
+            Import(_) => todo!(),
+            Expression(expression) => expression.return_type(),
         }
     }
 }
@@ -43,12 +68,7 @@ impl ReturnType for Expression {
                 let then_r = then_e.return_type()?;
                 let else_r = else_e.return_type()?;
 
-                let kind = if then_r.0 == ReturnKind::Hard && else_r.0 == ReturnKind::Hard {
-                    ReturnKind::Hard
-                } else {
-                    ReturnKind::Soft
-                };
-                Ok((kind, then_r.1))
+                Ok(pick_return(then_r, else_r))
             }
             Block(block) => block.return_type(),
             FunctionCall(fcall) => fcall.return_type(),
@@ -87,3 +107,24 @@ impl ReturnType for FunctionCall {
         Ok((ReturnKind::Soft, self.return_type.clone()))
     }
 }
+
+fn if_hard<TErr>(
+    return_type: (ReturnKind, TypeKind),
+    default: Result<(ReturnKind, TypeKind), TErr>,
+) -> Result<(ReturnKind, TypeKind), TErr> {
+    if let (ReturnKind::Hard, _) = return_type {
+        Ok(return_type)
+    } else {
+        default
+    }
+}
+
+pub fn pick_return<T>(lhs: (ReturnKind, T), rhs: (ReturnKind, T)) -> (ReturnKind, T) {
+    use ReturnKind::*;
+    match (lhs.0, rhs.0) {
+        (Hard, Hard) => (Hard, lhs.1),
+        (Hard, Soft) => (Soft, rhs.1),
+        (Soft, Hard) => (Soft, lhs.1),
+        (_, _) => (Soft, lhs.1),
+    }
+}