S.equals_ :: Setoid a => a -> a -> Boolean

index.js

@@ -550,6 +550,12 @@
   //. ```
   S.equals = def('equals', {}, [a, b, $.Boolean], Z.equals);
 
+  //# equals_ :: Setoid a => a -> a -> Boolean
+  //.
+  //. Variant of [`equals`](#equals) which requires two arguments of the
+  //. same type.
+  S.equals_ = def('equals_', {a: [Z.Setoid]}, [a, a, $.Boolean], Z.equals);
+
   //# concat :: Semigroup a => a -> a -> a
   //.
   //. Curried version of [`Z.concat`][].

test/equals.js

@@ -11,6 +11,7 @@ test('equals', function() {
   eq(S.equals.length, 2);
   eq(S.equals.toString(), 'equals :: a -> b -> Boolean');
 
+  eq(S.equals('foo', 42), false);
   eq(S.equals(S.Nothing, S.Nothing), true);
   eq(S.equals(S.Just(NaN), S.Just(NaN)), true);
   eq(S.equals(S.Just(0), S.Just(-0)), false);

test/equals_.js

@@ -0,0 +1,22 @@
+'use strict';
+
+var S = require('..');
+
+var eq = require('./internal/eq');
+
+
+test('equals_', function() {
+
+  eq(typeof S.equals_, 'function');
+  eq(S.equals_.length, 2);
+  eq(S.equals_.toString(), 'equals_ :: Setoid a => a -> a -> Boolean');
+
+  eq(S.equals_(S.Nothing, S.Nothing), true);
+  eq(S.equals_(S.Just(NaN), S.Just(NaN)), true);
+  eq(S.equals_(S.Just(0), S.Just(-0)), false);
+  eq(S.equals_(S.Left(NaN), S.Left(NaN)), true);
+  eq(S.equals_(S.Left(0), S.Left(-0)), false);
+  eq(S.equals_(S.Right(NaN), S.Right(NaN)), true);
+  eq(S.equals_(S.Right(0), S.Right(-0)), false);
+
+});