adds Num.subWrap

compiler/builtins/src/std.rs

@@ -104,6 +104,12 @@ pub fn types() -> MutMap<Symbol, (SolvedType, Region)> {
         ),
     );
 
+    // subWrap : Int, Int -> Int
+    add_type(
+        Symbol::NUM_SUB_WRAP,
+        top_level_function(vec![int_type(), int_type()], Box::new(int_type())),
+    );
+
     // mul or (*) : Num a, Num a -> Num a
     add_type(
         Symbol::NUM_MUL,

compiler/builtins/src/unique.rs

@@ -174,6 +174,12 @@ pub fn types() -> MutMap<Symbol, (SolvedType, Region)> {
         unique_function(vec![num_type(u, num), num_type(v, num)], num_type(w, num))
     });
 
+    // subWrap : Num a, Num a -> Num a
+    add_type(Symbol::NUM_SUB_WRAP, {
+        let_tvars! { u, v, w, num };
+        unique_function(vec![num_type(u, num), num_type(v, num)], num_type(w, num))
+    });
+
     // mul or (*) : Num a, Num a -> Num a
     add_type(Symbol::NUM_MUL, {
         let_tvars! { u, v, w, num };

compiler/can/src/builtins.rs

@@ -82,6 +82,7 @@ pub fn builtin_defs_map(symbol: Symbol, var_store: &mut VarStore) -> Option<Def>
         NUM_ADD_CHECKED => num_add_checked,
         NUM_ADD_WRAP => num_add_wrap,
         NUM_SUB => num_sub,
+        NUM_SUB_WRAP => num_sub_wrap,
         NUM_MUL => num_mul,
         NUM_GT => num_gt,
         NUM_GTE => num_gte,
@@ -472,6 +473,11 @@ fn num_sub(symbol: Symbol, var_store: &mut VarStore) -> Def {
     num_binop(symbol, var_store, LowLevel::NumSub)
 }
 
+/// Num.subWrap : Num a, Num a -> Num a
+fn num_sub_wrap(symbol: Symbol, var_store: &mut VarStore) -> Def {
+    num_binop(symbol, var_store, LowLevel::NumSubWrap)
+}
+
 /// Num.mul : Num a, Num a -> Num a
 fn num_mul(symbol: Symbol, var_store: &mut VarStore) -> Def {
     num_binop(symbol, var_store, LowLevel::NumMul)

compiler/gen/src/llvm/build.rs

@@ -3002,7 +3002,7 @@ fn run_low_level<'a, 'ctx, 'env>(
         }
 
         NumAdd | NumSub | NumMul | NumLt | NumLte | NumGt | NumGte | NumRemUnchecked
-        | NumAddWrap | NumAddChecked | NumDivUnchecked | NumPow | NumPowInt => {
+        | NumAddWrap | NumAddChecked | NumDivUnchecked | NumPow | NumPowInt | NumSubWrap => {
             debug_assert_eq!(args.len(), 2);
 
             let (lhs_arg, lhs_layout) = load_symbol_and_layout(env, scope, &args[0]);
@@ -3256,6 +3256,7 @@ fn build_int_binop<'a, 'ctx, 'env>(
 
             sub_result
         }
+        NumSubWrap => bd.build_int_sub(lhs, rhs, "sub_int").into(),
         NumMul => bd.build_int_mul(lhs, rhs, "mul_int").into(),
         NumGt => bd.build_int_compare(SGT, lhs, rhs, "int_gt").into(),
         NumGte => bd.build_int_compare(SGE, lhs, rhs, "int_gte").into(),

compiler/module/src/low_level.rs

@@ -31,6 +31,7 @@ pub enum LowLevel {
     NumAddWrap,
     NumAddChecked,
     NumSub,
+    NumSubWrap,
     NumMul,
     NumGt,
     NumGte,

compiler/module/src/symbol.rs

@@ -798,6 +798,7 @@ define_builtins! {
         55 NUM_ACOS: "acos"
         56 NUM_ASIN: "asin"
         57 NUM_BITWISE_AND: "bitwiseAnd"
+        58 NUM_SUB_WRAP: "subWrap"
     }
     2 BOOL: "Bool" => {
         0 BOOL_BOOL: "Bool" imported // the Bool.Bool type alias

compiler/mono/src/borrow.rs

@@ -539,7 +539,7 @@ pub fn lowlevel_borrow_signature(arena: &Bump, op: LowLevel) -> &[bool] {
         ListWalkBackwards => arena.alloc_slice_copy(&[borrowed, irrelevant, owned]),
         ListSum => arena.alloc_slice_copy(&[borrowed]),
 
-        Eq | NotEq | And | Or | NumAdd | NumAddWrap | NumAddChecked | NumSub | NumMul | NumGt
+        Eq | NotEq | And | Or | NumAdd | NumAddWrap | NumAddChecked | NumSub | NumSubWrap | NumMul | NumGt
         | NumGte | NumLt | NumLte | NumCompare | NumDivUnchecked | NumRemUnchecked | NumPow
         | NumPowInt | NumBitwiseAnd => arena.alloc_slice_copy(&[irrelevant, irrelevant]),