TreeCheckers use re-typing...

... to check whether tree types make sense. Still produces errors when enabled.

1 files changed, 31 insertions, 6 deletions

diff --git a/src/dotty/tools/dotc/transform/TreeChecker.scala b/src/dotty/tools/dotc/transform/TreeChecker.scala
index 5913875b8..f52c5bc1c 100644
--- a/src/dotty/tools/dotc/transform/TreeChecker.scala
+++ b/src/dotty/tools/dotc/transform/TreeChecker.scala
@@ -12,8 +12,10 @@ import core.Constants._
 import core.StdNames._
 import core.Decorators._
 import core.transform.Erasure.isUnboundedGeneric
+import typer._
 import typer.ErrorReporting._
 import ast.Trees._
+import ast.{tpd, untpd}
 
 /** This transform eliminates patterns. Right now it's a dummy.
  *  Awaiting the real pattern matcher.
@@ -23,14 +25,37 @@ class TreeChecker {
 
   def check(ctx: Context) = {
     println(s"checking ${ctx.compilationUnit} after phase ${ctx.phase.prev}")
-    Checker.transform(ctx.compilationUnit.tpdTree)(ctx)
+    Checker.typedExpr(ctx.compilationUnit.tpdTree)(ctx)
   }
 
-  object Checker extends TreeMap {
-    override def transform(tree: Tree)(implicit ctx: Context) = {
-      println(i"checking $tree")
-      assert(tree.isEmpty || tree.hasType, tree.show)
-      super.transform(tree)
+  object Checker extends ReTyper {
+    override def typed(tree: untpd.Tree, pt: Type)(implicit ctx: Context) =
+      if (tree.isEmpty) tree.asInstanceOf[Tree]
+      else {
+        assert(tree.hasType, tree.show)
+        val tree1 = super.typed(tree, pt)
+        def sameType(tp1: Type, tp2: Type) =
+          (tp1 eq tp2) || // accept NoType / NoType
+          (tp1 =:= tp2)
+        def divergenceMsg =
+          s"""Types differ
+           |Original type : ${tree.typeOpt.show}
+           |After checking: ${tree1.tpe.show}
+           |Original tree : ${tree.show}
+           |After checking: ${tree1.show}
+        """.stripMargin
+        assert(sameType(tree1.tpe, tree.typeOpt), divergenceMsg)
+        tree1
+      }
+
+    override def typedIdent(tree: untpd.Ident, pt: Type)(implicit ctx: Context): Tree = {
+      assert(tree.isTerm, tree.show)
+      super.typedIdent(tree, pt)
+    }
+
+    override def typedSelect(tree: untpd.Select, pt: Type)(implicit ctx: Context): Tree = {
+      assert(tree.isTerm, tree.show)
+      super.typedSelect(tree, pt)
     }
   }
 }