Add binop_hint

reid/src/mir/implement.rs

@@ -107,6 +107,16 @@ impl TypeKind {
         }
     }
 
+    pub fn binop_hint(&self, op: &BinaryOperator) -> Option<TypeKind> {
+        match op {
+            BinaryOperator::Add | BinaryOperator::Minus | BinaryOperator::Mult => {
+                Some(self.clone())
+            }
+            BinaryOperator::And => None,
+            BinaryOperator::Cmp(_) => None,
+        }
+    }
+
     pub fn signed(&self) -> bool {
         match self {
             TypeKind::Bool => false,

reid/src/mir/typecheck.rs

@@ -408,7 +408,11 @@ impl Expression {
             ExprKind::BinOp(op, lhs, rhs) => {
                 // TODO make sure lhs and rhs can actually do this binary
                 // operation once relevant
-                let lhs_res = lhs.typecheck(state, &typerefs, hint_t);
+                let lhs_res = lhs.typecheck(
+                    state,
+                    &typerefs,
+                    hint_t.and_then(|t| t.binop_hint(op)).as_ref(),
+                );
                 let lhs_type = state.or_else(lhs_res, TypeKind::Vague(Vague::Unknown), lhs.1);
                 let rhs_res = rhs.typecheck(state, &typerefs, Some(&lhs_type));
                 let rhs_type = state.or_else(rhs_res, TypeKind::Vague(Vague::Unknown), rhs.1);

reid_src/float.reid

@@ -5,5 +5,5 @@ pub fn OneHalf(var1: f32) -> f32 {
 }
 
 pub fn main() -> bool {
-  return 7.5 > 5.5;
+  return (7.5 > 5.5);
 }