TailRec phase and tests for it.

Ported tailcall phase from scalac with such changes:
  - all transformation is done in the phase itself
     (previously half of the work was done in backend)
  - it is now able to run before uncurry
  - it is now a treeTransform
  - renamed to tailrec to make it more obvious that
     this phase transforms only recursive calls.

For now this is a single phase which speculatively
transforms DefDefs.
Speculation can be potentially removed by
splitting into 2 phases:
  one detecting which methods should be transformed
  second performing transformation.

But, as transformation requires as same amount of work
as detection, I believe it will be simpler to maintain
it as a single phase.

Conflicts:
	tests/pos/typers.scala

1 files changed, 9 insertions, 0 deletions

diff --git a/test/dotc/tests.scala b/test/dotc/tests.scala
index 3228c3474..29c50c556 100644
--- a/test/dotc/tests.scala
+++ b/test/dotc/tests.scala
@@ -47,6 +47,9 @@ class tests extends CompilerTest {
   @Test def pos_i39 = compileFile(posDir, "i39", doErase)
   @Test def pos_overloadedAccess = compileFile(posDir, "overloadedAccess", doErase)
   @Test def pos_approximateUnion = compileFile(posDir, "approximateUnion", doErase)
+  @Test def pos_tailcall = compileDir(posDir + "tailcall/", doErase)
+
+
 
   @Test def pos_all = compileFiles(posDir, twice)
   @Test def new_all = compileFiles(newDir, twice)
@@ -69,6 +72,12 @@ class tests extends CompilerTest {
   @Test def neg_t0625_structural = compileFile(negDir, "t0625", xerrors = 1)
   @Test def neg_t0654_polyalias = compileFile(negDir, "t0654", xerrors = 2)
   @Test def neg_t1192_legalPrefix = compileFile(negDir, "t1192", xerrors = 1)
+  @Test def neg_tailcall_t1672b = compileFile(negDir, "tailcall/t1672b", xerrors = 6)
+  @Test def neg_tailcall_t3275 = compileFile(negDir, "tailcall/t3275", xerrors = 1)
+  @Test def neg_tailcall_t6574 = compileFile(negDir, "tailcall/t6574", xerrors = 4)
+  @Test def neg_tailcall = compileFile(negDir, "tailcall/tailrec", xerrors = 7)
+  @Test def neg_tailcall2 = compileFile(negDir, "tailcall/tailrec-2", xerrors = 2)
+  @Test def neg_tailcall3 = compileFile(negDir, "tailcall/tailrec-3", xerrors = 2)
 
   @Test def dotc = compileDir(dotcDir + "tools/dotc", twice)
   @Test def dotc_ast = compileDir(dotcDir + "tools/dotc/ast", twice)