From 15e9ef8f083e0c0dc75bf51a0784f56df2e2bea8 Mon Sep 17 00:00:00 2001 From: Jason Zaugg Date: Wed, 17 Apr 2013 09:19:21 +0200 Subject: SI-7377 Fix retypechecking of patterns on case companion alias Some ancient code in Typers switches from PATTERNmode to EXPRmode when encountering `stableF(...)`. It just typechecks `stableF` and discards the arguments. To the best of Martin's recollection, this has something to do with the need to typecheck patterns rather late in the compiler, after `a.b` had been translated to `a.b()` in `Uncurry`. I'm not able to motivate this with tests using `-Xoldpatmat`; was there ever an even older pattern matcher that ran *after* uncurry? What changed in 2.10.1 to expose this wrinkle? dfbaaa17 fixed `TypeTree.copyAttrs` to copy the original tree. During the descent of `ResetAttrs`, sub-trees are duplicated before begin further transformed. Duplicating the `Match` in 2.10.0 would forget that the original tree of: pat = (a: Int)Foo(_) `----------` `- TypeTree((a: Int)Foo), with original Select(..., "FooAlias") The retypechecking would operate on the `MethodType`, rather than the `Select`, which was not considered a stable application. For 2.10.x, I've just tightened up the condition to only hit this if `args` is empty. I'm almost certain that the code can be removed altogether, and I'll do that when this is merged to master. --- test/files/pos/t7377/Client_2.scala | 11 +++++++++++ test/files/pos/t7377/Macro_1.scala | 7 +++++++ test/files/pos/t7377b.flags | 1 + test/files/pos/t7377b.scala | 13 +++++++++++++ 4 files changed, 32 insertions(+) create mode 100644 test/files/pos/t7377/Client_2.scala create mode 100644 test/files/pos/t7377/Macro_1.scala create mode 100644 test/files/pos/t7377b.flags create mode 100644 test/files/pos/t7377b.scala (limited to 'test/files') diff --git a/test/files/pos/t7377/Client_2.scala b/test/files/pos/t7377/Client_2.scala new file mode 100644 index 0000000000..5728956cca --- /dev/null +++ b/test/files/pos/t7377/Client_2.scala @@ -0,0 +1,11 @@ +object Test { + M.noop(List(1) match { case Nil => 0; case (x::xs) => x }) + + case class Foo(a: Int) + val FooAlias: Foo.type = Foo + M.noop(Foo(0) match { case FooAlias(_) => 0 }) + + case class Bar() + val BarAlias: Bar.type = Bar + M.noop(Bar() match { case BarAlias() => 0 }) +} diff --git a/test/files/pos/t7377/Macro_1.scala b/test/files/pos/t7377/Macro_1.scala new file mode 100644 index 0000000000..a0ec1d84af --- /dev/null +++ b/test/files/pos/t7377/Macro_1.scala @@ -0,0 +1,7 @@ +import language.experimental._ +import reflect.macros.Context + +object M { + def noopImpl[A](c: Context)(expr: c.Expr[A]): c.Expr[A] = c.Expr(c.typeCheck(c.resetLocalAttrs(expr.tree))) + def noop[A](expr: A): A = macro noopImpl[A] +} diff --git a/test/files/pos/t7377b.flags b/test/files/pos/t7377b.flags new file mode 100644 index 0000000000..cb8324a345 --- /dev/null +++ b/test/files/pos/t7377b.flags @@ -0,0 +1 @@ +-Xoldpatmat \ No newline at end of file diff --git a/test/files/pos/t7377b.scala b/test/files/pos/t7377b.scala new file mode 100644 index 0000000000..aeee800d57 --- /dev/null +++ b/test/files/pos/t7377b.scala @@ -0,0 +1,13 @@ +object Test { + List(1) match { case Nil => 0; case (x::xs) => x } + + case class Foo(a: Int) + val FooAlias: Foo.type = Foo + Foo(0) match { case FooAlias(_) => 0 } + Foo(0) match { case Foo(_) => 0 } + + case class Bar() + val BarAlias: Bar.type = Bar + Bar() match { case BarAlias() => 0 } + Bar() match { case Bar() => 0 } +} -- cgit v1.2.3