Single Abstract Method support: synthesize SAMs

Under `-Xexperimental`, `typedFunction` invokes `synthesizeSAMFunction`
when the expected type for the function literal (`pt`) is not the built-in
`FunctionN` type of the expected arity, but `pt` does have a SAM
with the expected number of arguments.

PS: We'll require `import language.sam` instead of `-Xexperimental`,
as soon as the SIP is ready and there are more tests.

1 files changed, 9 insertions, 0 deletions

diff --git a/test/files/pos/sammy_twice.scala b/test/files/pos/sammy_twice.scala
new file mode 100644
index 0000000000..c91f5b9fd2
--- /dev/null
+++ b/test/files/pos/sammy_twice.scala
@@ -0,0 +1,9 @@
+// test repeated synthesizeSAMFunction where the sam type is not fully defined
+// the naive implementation would enter the same apply$body in the same scope twice
+trait F[T, U] { def apply(x: T): U }
+
+class C {
+  def app[T, U](x: T)(f: F[T, U]): U = f(x)
+  app(1)(x => List(x))
+  app(2)(x => List(x))
+}
\ No newline at end of file