Merge pull request #4181 from dotty-staging/fix/boolean-eq

Fix #4180: Can't compare Scala and Java Booleans

Author: smarter

library/src/scala/Eq.scala

@@ -55,4 +55,7 @@ object Eq extends Eq[Any, Any] {
   implicit def eqNumFloat : Eq[Number, Float]  = Eq
   implicit def eqDoubleNum: Eq[Double, Number] = Eq
   implicit def eqNumDouble: Eq[Number, Double] = Eq
-}
+
+  implicit def eqSBoolJBool: Eq[Boolean, java.lang.Boolean] = Eq
+  implicit def eqJBoolSBool: Eq[java.lang.Boolean, Boolean] = Eq
+}

tests/neg/equality.scala

@@ -58,8 +58,8 @@ object equality {
 
     1 == true  // error
 
-    null == true // OK by eqProxy
-    true == null // error
+    null == true // OK by eqProxy or eqJBoolSBool
+    true == null // OK by eqSBoolJBool
     null == 1    // OK by eqProxy or eqNumInt
     1 == null    // OK by eqIntNum
 

tests/pos/i4180.scala

@@ -0,0 +1,6 @@
+object Test {
+  def foo(s: Boolean, j: java.lang.Boolean) = {
+    val a = s == j
+    val b = j == s
+  }
+}