Check AppliedTypeTrees bounds inside AppliedTypeTree

Author: smarter

src/dotty/tools/dotc/typer/Checking.scala

@@ -50,13 +50,16 @@ object Checking {
 
   /** Check all AppliedTypeTree nodes in this tree for legal bounds */
   val boundsChecker = new TreeTraverser {
-    def traverse(tree: Tree)(implicit ctx: Context) = tree match {
-      case AppliedTypeTree(tycon, args) =>
-        val tparams = tycon.tpe.typeSymbol.typeParams
-        val bounds = tparams.map(tparam =>
-          tparam.info.asSeenFrom(tycon.tpe.normalizedPrefix, tparam.owner.owner).bounds)
-        checkBounds(args, bounds, _.substDealias(tparams, _))
-      case _ => traverseChildren(tree)
+    def traverse(tree: Tree)(implicit ctx: Context) = {
+      tree match {
+        case AppliedTypeTree(tycon, args) =>
+          val tparams = tycon.tpe.typeSymbol.typeParams
+          val bounds = tparams.map(tparam =>
+            tparam.info.asSeenFrom(tycon.tpe.normalizedPrefix, tparam.owner.owner).bounds)
+          checkBounds(args, bounds, _.substDealias(tparams, _))
+        case _ =>
+      }
+      traverseChildren(tree)
     }
   }
 

test/dotc/tests.scala

@@ -176,6 +176,7 @@ class tests extends CompilerTest {
   @Test def neg_validateParsing = compileFile(negDir, "validate-parsing", xerrors = 7)
   @Test def neg_validateRefchecks = compileFile(negDir, "validate-refchecks", xerrors = 2)
   @Test def neg_skolemize = compileFile(negDir, "skolemize", xerrors = 2)
+  @Test def neg_nested_bounds = compileFile(negDir, "nested_bounds", xerrors = 1)
 
   @Test def run_all = runFiles(runDir)
 

tests/neg/nested_bounds.scala

@@ -0,0 +1,5 @@
+class OnlyInt[T <: Int]
+
+object Test {
+  type T = List[OnlyInt[String]] // error: Type argument String does not conform to upper bound Int
+}