diff options
author | James Iry <jamesiry@gmail.com> | 2013-02-20 15:31:32 -0800 |
---|---|---|
committer | James Iry <jamesiry@gmail.com> | 2013-02-21 09:02:37 -0800 |
commit | 1b6661b8b586637ba5d54510c7bda1144acab23b (patch) | |
tree | 8abb70e9fd764f4dd4aff09dd12c015cdd723fdf /test/files | |
parent | 70956e560a11996e1d801d59b312dfe9d56b7a74 (diff) | |
download | scala-1b6661b8b586637ba5d54510c7bda1144acab23b.tar.gz scala-1b6661b8b586637ba5d54510c7bda1144acab23b.tar.bz2 scala-1b6661b8b586637ba5d54510c7bda1144acab23b.zip |
SI-7015 Removes redundant aconst_null; pop; aconst_null creation
In an effort to adapt methods and field accesses of type Null to
other types, we were always emitting
aconst_null
pop
aconst_null
The problem is we were doing that even when the JVM was in a position
to know it had null value, e.g. when the user had written a null
constant. This commit fixes that and includes a test to show that the
resulting byte code still works even without repeating ourselves and/or
repeating ourselves.
This commit also makes the scala.runtim.Null$ constructor private. It
was a sealed abstract class which prevented subclassing in Scala, but
it didn't prevent subclassing in Java. A private constructor takes care
of that hole so now the only value of type Null$ should be null.
Along the way I found some other questionable things in adapt and I've
added TODO's and issue https://issues.scala-lang.org/browse/SI-7159 to
track.
Diffstat (limited to 'test/files')
-rw-r--r-- | test/files/run/t7015.check | 11 | ||||
-rw-r--r-- | test/files/run/t7015.scala | 49 |
2 files changed, 60 insertions, 0 deletions
diff --git a/test/files/run/t7015.check b/test/files/run/t7015.check new file mode 100644 index 0000000000..7651fe06b0 --- /dev/null +++ b/test/files/run/t7015.check @@ -0,0 +1,11 @@ +Method returns Null type: null +Method takes non Null type: null +call through method null +call through bridge null +fetch field: null +fetch field on companion: null +fetch local: null +fetch array element: null +method that takes object: null +method that takes anyref: null +method that takes any: null diff --git a/test/files/run/t7015.scala b/test/files/run/t7015.scala new file mode 100644 index 0000000000..9344ca2906 --- /dev/null +++ b/test/files/run/t7015.scala @@ -0,0 +1,49 @@ +object Test { + def main(args : Array[String]) : Unit = { + println(s"Method returns Null type: $f") + println(s"Method takes non Null type: ${g(null)}") + + // pass things through the g function because it expects + // a string. If we haven't adapted properly then we'll + // get verify errors + val b = new B + println(s"call through method ${g(b.f(null))}") + println(s"call through bridge ${g((b: A).f(null))}") + + println(s"fetch field: ${g(b.nullField)}") + println(s"fetch field on companion: ${g(B.nullCompanionField)}") + + val x = f + println(s"fetch local: ${g(x)}") + + val nulls = Array(f, f, f) + println(s"fetch array element: ${g(nulls(0))}") + + println(s"method that takes object: ${q(f)}") + println(s"method that takes anyref: ${r(f)}") + println(s"method that takes any: ${s(f)}") + } + + def f = null + + def g(x: String) = x + + def q(x: java.lang.Object) = x + def r(x: AnyRef) = x + def s(x: Any) = x +} + +abstract class A { + def f(x: String): String +} + +class B extends A { + val nullField = null + + // this forces a bridge method because the return type is different + override def f(x: String) : Null = null +} + +object B { + val nullCompanionField = null +}
\ No newline at end of file |