SI-7533 Adds Symbol.isAbstract

Amazingly enough, we've missed the fact that non-type symbols can also
be abstract. Having been enlightened by this, I'm exposing isDeferred
and merging it along with isAbstractType and isAbstractClass into the
unified Symbol.isAbstract method.

1 files changed, 30 insertions, 0 deletions

diff --git a/test/files/run/t7533.check b/test/files/run/t7533.check
new file mode 100644
index 0000000000..fa5b3edc8f
--- /dev/null
+++ b/test/files/run/t7533.check
@@ -0,0 +1,30 @@
+Testing Symbol.isAbstract...
+=======class C=======
+class C => true
+constructor C => false
+value x1 => true
+value x2 => false
+value x2 => false
+method y1 => true
+method y2 => false
+type T1 => true
+type T2 => false
+=======trait T=======
+trait T => true
+method $init$ => false
+value z1 => true
+value z2 => false
+value z2 => false
+method w1 => true
+method w2 => false
+type U1 => true
+type U2 => false
+=======class D=======
+class D => false
+constructor D => false
+value x1 => false
+value x1 => false
+method y1 => false
+=======object M=======
+object M => false
+constructor M => false