ArithmeticExceptions are no more undefined behavior in Scala.js 1.x.

Author: sjrd

doc/semantics.md

@@ -103,7 +103,6 @@ Currently known exhaustive list of exceptions are:
 * `NullPointerException`
 * `ArrayIndexOutOfBoundsException` and `StringIndexOutOfBoundsException`
 * `ClassCastException`
-* `ArithmeticException` (such as integer division by 0)
 * `StackOverflowError` and other `VirtualMachineError`s
 
 Because Scala.js does not receive VM support to detect such erroneous
@@ -112,6 +111,10 @@ conditions, checking them is typically too expensive.
 Therefore, all of these are considered
 [undefined behavior](http://en.wikipedia.org/wiki/Undefined_behavior).
 
+**Scala.js 0.6.x only:**
+In Scala.js 0.6.x, `ArithmeticException`s, such as integer division by 0, are also considered undefined behavior.
+This is not the case in Scala.js 1.x anymore, where they are reliably thrown.
+
 Some of these, however, can be configured to be compliant with the JVM
 specification using sbt settings.
 Currently, only `ClassCastException`s (thrown by invalid `asInstanceOf` calls)