nac3core/src/codegen/expr.rs

@@ -298,8 +298,40 @@ impl<'ctx, 'a> CodeGenContext<'ctx, 'a> {
             (Operator::BitOr, _) => self.builder.build_or(lhs, rhs, "or").into(),
             (Operator::BitXor, _) => self.builder.build_xor(lhs, rhs, "xor").into(),
             (Operator::BitAnd, _) => self.builder.build_and(lhs, rhs, "and").into(),
-            (Operator::LShift, _) => self.builder.build_left_shift(lhs, rhs, "lshift").into(),
-            (Operator::RShift, _) => self.builder.build_right_shift(lhs, rhs, true, "rshift").into(),
+
+            // Sign-ness of bitshift operators are always determined by the left operand
+            (Operator::LShift, signed) | (Operator::RShift, signed) => {
+                // RHS operand is always 32 bits
+                assert_eq!(rhs.get_type().get_bit_width(), 32);
+
+                let common_type = lhs.get_type();
+                let rhs = if common_type.get_bit_width() > 32 {
+                    if signed {
+                        self.builder.build_int_s_extend(rhs, common_type, "")
+                    } else {
+                        self.builder.build_int_z_extend(rhs, common_type, "")
+                    }
+                } else {
+                    rhs
+                };
+
+                let rhs_gez = self.builder.build_int_compare(IntPredicate::SGE, rhs, common_type.const_zero(), "");
+                self.make_assert(
+                    generator,
+                    rhs_gez,
+                    "ValueError",
+                    "negative shift count",
+                    [None, None, None],
+                    self.current_loc
+                );
+
+                match *op {
+                    Operator::LShift => self.builder.build_left_shift(lhs, rhs, "lshift").into(),
+                    Operator::RShift => self.builder.build_right_shift(lhs, rhs, signed, "rshift").into(),
+                    _ => unreachable!()
+                }
+            }
+
             (Operator::FloorDiv, true) => self.builder.build_int_signed_div(lhs, rhs, "floordiv").into(),
             (Operator::FloorDiv, false) => self.builder.build_int_unsigned_div(lhs, rhs, "floordiv").into(),
             (Operator::Pow, s) => integer_power(generator, self, lhs, rhs, s).into(),
@@ -1085,6 +1117,9 @@ pub fn gen_binop_expr<'ctx, 'a, G: CodeGenerator>(
         Ok(Some(ctx.gen_int_ops(generator, op, left_val, right_val, true).into()))
     } else if ty1 == ty2 && [ctx.primitives.uint32, ctx.primitives.uint64].contains(&ty1) {
         Ok(Some(ctx.gen_int_ops(generator, op, left_val, right_val, false).into()))
+    } else if [Operator::LShift, Operator::RShift].contains(op) {
+        let signed = [ctx.primitives.int32, ctx.primitives.int64].contains(&ty1);
+        Ok(Some(ctx.gen_int_ops(generator, op, left_val, right_val, signed).into()))
     } else if ty1 == ty2 && ctx.primitives.float == ty1 {
         Ok(Some(ctx.gen_float_ops(op, left_val, right_val).into()))
     } else if ty1 == ctx.primitives.float && ty2 == ctx.primitives.int32 {

nac3core/src/typecheck/function_check.rs

@@ -2,7 +2,7 @@ use crate::typecheck::typedef::TypeEnum;
 
 use super::type_inferencer::Inferencer;
 use super::typedef::Type;
-use nac3parser::ast::{self, Expr, ExprKind, Stmt, StmtKind, StrRef};
+use nac3parser::ast::{self, Constant, Expr, ExprKind, Operator::{LShift, RShift}, Stmt, StmtKind, StrRef};
 use std::{collections::HashSet, iter::once};
 
 impl<'a> Inferencer<'a> {
@@ -107,11 +107,28 @@ impl<'a> Inferencer<'a> {
                 self.check_expr(value, defined_identifiers)?;
                 self.should_have_value(value)?;
             }
-            ExprKind::BinOp { left, right, .. } => {
+            ExprKind::BinOp { left, op, right } => {
                 self.check_expr(left, defined_identifiers)?;
                 self.check_expr(right, defined_identifiers)?;
                 self.should_have_value(left)?;
                 self.should_have_value(right)?;
+
+                // Check whether a bitwise shift has a negative RHS constant value
+                if *op == LShift || *op == RShift {
+                    if let ExprKind::Constant { value, .. } = &right.node {
+                        let rhs_val = match value {
+                            Constant::Int(v) => v,
+                            _ => unreachable!(),
+                        };
+
+                        if *rhs_val < 0 {
+                            return Err(format!(
+                                "shift count is negative at {}",
+                                right.location
+                            ));
+                        }
+                    }
+                }
             }
             ExprKind::UnaryOp { operand, .. } => {
                 self.check_expr(operand, defined_identifiers)?;

nac3core/src/typecheck/magic_methods.rs

@@ -96,11 +96,13 @@ pub fn impl_binop(
             let (ty, var_id) = unifier.get_fresh_var_with_range(other_ty, Some("N".into()), None);
             (ty, Some(var_id))
         };
+
         let function_vars = if let Some(var_id) = other_var_id {
             vec![(var_id, other_ty)].into_iter().collect::<HashMap<_, _>>()
         } else {
             HashMap::new()
         };
+
         for op in ops {
             fields.insert(binop_name(op).into(), {
                 (
@@ -224,7 +226,7 @@ pub fn impl_bitwise_arithmetic(unifier: &mut Unifier, store: &PrimitiveStore, ty
 
 /// LShift, RShift
 pub fn impl_bitwise_shift(unifier: &mut Unifier, store: &PrimitiveStore, ty: Type) {
-    impl_binop(unifier, store, ty, &[ty], ty, &[ast::Operator::LShift, ast::Operator::RShift])
+    impl_binop(unifier, store, ty, &[store.int32, store.uint32], ty, &[ast::Operator::LShift, ast::Operator::RShift]);
 }
 
 /// Div
@@ -295,6 +297,7 @@ pub fn set_primitives_magic_methods(store: &PrimitiveStore, unifier: &mut Unifie
         uint64: uint64_t,
         ..
     } = *store;
+
     /* int ======== */
     for t in [int32_t, int64_t, uint32_t, uint64_t] {
         impl_basic_arithmetic(unifier, store, t, &[t], t);

nac3core/src/typecheck/typedef/mod.rs

@@ -116,6 +116,7 @@ impl RecordField {
     }
 }
 
+/// Category of variable and value types.
 #[derive(Clone)]
 pub enum TypeEnum {
     TRigidVar {
@@ -123,6 +124,8 @@ pub enum TypeEnum {
         name: Option<StrRef>,
         loc: Option<Location>,
     },
+
+    /// A type variable.
     TVar {
         id: u32,
         // empty indicates this is not a struct/tuple/list
@@ -132,21 +135,41 @@ pub enum TypeEnum {
         name: Option<StrRef>,
         loc: Option<Location>,
     },
+
+    /// A tuple type.
     TTuple {
+        /// The types of elements present in this tuple.
         ty: Vec<Type>,
     },
+
+    /// A list type.
     TList {
+        /// The type of elements present in this list.
         ty: Type,
     },
+
+    /// An object type.
     TObj {
+        /// The [DefintionId] of this object type.
         obj_id: DefinitionId,
+
+        /// The fields present in this object type.
+        ///
+        /// The key of the [Mapping] is the identifier of the field, while the value is a tuple
+        /// containing the [Type] of the field, and a `bool` indicating whether the field is a
+        /// variable (as opposed to a function).
         fields: Mapping<StrRef, (Type, bool)>,
+
+        /// Mapping between the ID of type variables and the [Type] representing the type variables
+        /// of this object type.
         params: VarMap,
     },
     TVirtual {
         ty: Type,
     },
     TCall(Vec<CallId>),
+
+    /// A function type.
     TFunc(FunSignature),
 }
 
@@ -294,11 +317,16 @@ impl Unifier {
         self.get_fresh_var_with_range(&[], None, None)
     }
 
+    /// Returns a fresh [type variable][TypeEnum::TVar] with no associated range.
+    ///
+    /// This type variable can be instantiated by any type.
     pub fn get_fresh_var(&mut self, name: Option<StrRef>, loc: Option<Location>) -> (Type, u32) {
         self.get_fresh_var_with_range(&[], name, loc)
     }
 
-    /// Get a fresh type variable.
+    /// Returns a fresh [type variable][TypeEnum::TVar] with the range specified by `range`.
+    ///
+    /// This type variable can be instantiated by any type present in `range`.
     pub fn get_fresh_var_with_range(
         &mut self,
         range: &[Type],

nac3standalone/demo/src/numeric_primitives.py

@@ -41,10 +41,10 @@ def u64_max() -> uint64:
     return ~uint64(0)
 
 def i64_min() -> int64:
-    return int64(1) << int64(63)
+    return int64(1) << 63
 
 def i64_max() -> int64:
-    return ~(int64(1) << int64(63))
+    return ~(int64(1) << 63)
 
 def test_u32_bnot():
     output_uint32(~uint32(0))

nac3standalone/demo/src/operators.py

@@ -37,7 +37,9 @@ def test_int32():
     output_int32(a ^ b)
     output_int32(a & b)
     output_int32(a << b)
+    output_int32(a << uint32(b))
     output_int32(a >> b)
+    output_int32(a >> uint32(b))
     output_float64(a / b)
     a += b
     output_int32(a)
@@ -74,7 +76,9 @@ def test_uint32():
     output_uint32(a ^ b)
     output_uint32(a & b)
     output_uint32(a << b)
+    output_uint32(a << int32(b))
     output_uint32(a >> b)
+    output_uint32(a >> int32(b))
     output_float64(a / b)
     a += b
     output_uint32(a)
@@ -108,8 +112,10 @@ def test_int64():
     output_int64(a | b)
     output_int64(a ^ b)
     output_int64(a & b)
-    output_int64(a << b)
-    output_int64(a >> b)
+    output_int64(a << int32(b))
+    output_int64(a << uint32(b))
+    output_int64(a >> int32(b))
+    output_int64(a >> uint32(b))
     output_float64(a / b)
     a += b
     output_int64(a)
@@ -127,9 +133,9 @@ def test_int64():
     output_int64(a)
     a &= b
     output_int64(a)
-    a <<= b
+    a <<= int32(b)
     output_int64(a)
-    a >>= b
+    a >>= int32(b)
     output_int64(a)
 
 def test_uint64():
@@ -143,8 +149,8 @@ def test_uint64():
     output_uint64(a | b)
     output_uint64(a ^ b)
     output_uint64(a & b)
-    output_uint64(a << b)
-    output_uint64(a >> b)
+    output_uint64(a << uint32(b))
+    output_uint64(a >> uint32(b))
     output_float64(a / b)
     a += b
     output_uint64(a)
@@ -162,9 +168,9 @@ def test_uint64():
     output_uint64(a)
     a &= b
     output_uint64(a)
-    a <<= b
+    a <<= uint32(b)
     output_uint64(a)
-    a >>= b
+    a >>= uint32(b)
     output_uint64(a)
 
 class A: