Merge pull request scala#4021 from retronym/ticket/8869

retronym · retronym · commit 192d65f718ab · 2014-10-02T21:44:08.000+10:00
SI-8869 Prevent ill-kindedness in type lambdas
diff --git a/src/compiler/scala/tools/nsc/typechecker/Contexts.scala b/src/compiler/scala/tools/nsc/typechecker/Contexts.scala
@@ -480,6 +480,8 @@ trait Contexts { self: Analyzer =>
       // SI-8245 `isLazy` need to skip lazy getters to ensure `return` binds to the right place
       c.enclMethod         = if (isDefDef && !owner.isLazy) c else enclMethod
 
+      if (tree != outer.tree) c(TypeConstructorAllowed) = false
+
       registerContext(c.asInstanceOf[analyzer.Context])
       debuglog("[context] ++ " + c.unit + " / " + tree.summaryString)
       c
diff --git a/test/files/neg/t8869.check b/test/files/neg/t8869.check
@@ -0,0 +1,7 @@
+t8869.scala:5: error: class Option takes type parameters
+  def value: TC[({type l1[x] = Option})#l1] = ??? // error not reported!
+                               ^
+t8869.scala:7: error: class Option takes type parameters
+  type l2[x] = Option // error correctly reported
+               ^
+two errors found
diff --git a/test/files/neg/t8869.scala b/test/files/neg/t8869.scala
@@ -0,0 +1,10 @@
+class TC[T[_]] {
+  def identity[A](a: T[A]): T[A] = a
+}
+object Test {
+  def value: TC[({type l1[x] = Option})#l1] = ??? // error not reported!
+
+  type l2[x] = Option // error correctly reported
+  def value1: TC[l2] = ???
+}
+

Original file line number	Diff line number	Diff line change
`@@ -480,6 +480,8 @@ trait Contexts { self: Analyzer =>`
`480`	`480`	// SI-8245 `isLazy` need to skip lazy getters to ensure `return` binds to the right place
`481`	`481`	`c.enclMethod = if (isDefDef && !owner.isLazy) c else enclMethod`
`482`	`482`
	`483`	`+ if (tree != outer.tree) c(TypeConstructorAllowed) = false`
	`484`	`+`
`483`	`485`	`registerContext(c.asInstanceOf[analyzer.Context])`
`484`	`486`	`debuglog("[context] ++ " + c.unit + " / " + tree.summaryString)`
`485`	`487`	`c`