Change of TERMREFsymbol/TYPEREFsymbol semantics

Used to be "with fixed sym". Now it is: With initial symbol
as given in the serialized info.

It turns out the only previous uses of (TERM|TYPE)REFsymbol were
types that were made symbolic in self types. But exactly that caused
that problems in unpickling which we tried to workaround by changing
WithFixedSym#newLikeThis. And these fixes became less and less intuitive and
still could not solve the problem for good. Last hurdle was pickle-testing
all files in ast together.

It's much simpler to reserve (TERM|TYPE)REFsymbol for NamedTypes that have
an initial symbol. Like the previous "WithFixedSym" pickling, this avoids
inifinite recursions in pickling/extmethods.scala. But it also avoids problens
with unpickling ast/*.scala. The reason it is better is that it more accurately
models that types that exist before pickling.

This change also undoes previous changes to WithFixedSym#newlikeThis. Better to keep
the more restrictive contract for these.

1 files changed, 2 insertions, 3 deletions

diff --git a/test/dotc/tests.scala b/test/dotc/tests.scala
index 388f5ae23..d1b5538dc 100644
--- a/test/dotc/tests.scala
+++ b/test/dotc/tests.scala
@@ -39,9 +39,8 @@ class tests extends CompilerTest {
 
   @Test def pickle_pickleOK = compileDir(picklingDir, testPickling)
   @Test def pickle_pickling = compileDir(dotcDir + "tools/dotc/core/pickling/", testPickling)
-  @Test def pickle_Trees = compileFile(dotcDir, "tools/dotc/ast/Trees", testPickling)
-  @Test def pickle_untpd = compileFile(dotcDir, "tools/dotc/ast/untpd", testPickling)
-
+  @Test def pickle_ast = compileDir(dotcDir + "tools/dotc/ast/", testPickling)
+  
   //@Test def pickle_core = compileDir(dotcDir + "tools/dotc/core", testPickling, xerrors = 2) // two spurious comparison errors in Types and TypeOps
 
   @Test def pos_t2168_pat = compileFile(posDir, "t2168", twice)