Merge pull request #3905 from gourlaysama/wip/t5691-2

SI-5691 lint warning when a type parameter shadows an existing type.

7 files changed, 59 insertions, 7 deletions

diff --git a/test/files/neg/forgot-interpolator.scala b/test/files/neg/forgot-interpolator.scala
index a53054d890..ca1ac30821 100644
--- a/test/files/neg/forgot-interpolator.scala
+++ b/test/files/neg/forgot-interpolator.scala
@@ -54,8 +54,8 @@ package test {
     }
   }
   import annotation._
-  @implicitNotFound("No Z in ${A}")   // no warn
-  class Z[A]
+  @implicitNotFound("No Z in ${T}")   // no warn
+  class Z[T]
 }
 
 
diff --git a/test/files/neg/t4851.check b/test/files/neg/t4851.check
index 132dd91b50..d5711a889b 100644
--- a/test/files/neg/t4851.check
+++ b/test/files/neg/t4851.check
@@ -29,13 +29,13 @@ S.scala:7: warning: Adapting argument list by creating a 3-tuple: this may not b
   val y2 = new Some(1, 2, 3)
            ^
 S.scala:9: warning: Adaptation of argument list by inserting () has been deprecated: this is unlikely to be what you want.
-        signature: J2[T](x: T): J2[T]
+        signature: J2(x: T): J2[T]
   given arguments: <none>
  after adaptation: new J2((): Unit)
   val z1 = new J2
            ^
 S.scala:10: warning: Adaptation of argument list by inserting () has been deprecated: this is unlikely to be what you want.
-        signature: J2[T](x: T): J2[T]
+        signature: J2(x: T): J2[T]
   given arguments: <none>
  after adaptation: new J2((): Unit)
   val z2 = new J2()
diff --git a/test/files/neg/t4851/J2.java b/test/files/neg/t4851/J2.java
index 82954d9489..a90f48e269 100644
--- a/test/files/neg/t4851/J2.java
+++ b/test/files/neg/t4851/J2.java
@@ -1,11 +1,11 @@
 public class J2<T> {
   T x;
 
-  public <T> J(T x) {
+  public J2(T x) {
     this.x = x;
   }
 
   public String toString() {
     return "J2:" + x.getClass();
   }
-}
\ No newline at end of file
+}
diff --git a/test/files/neg/t5691.check b/test/files/neg/t5691.check
new file mode 100644
index 0000000000..a51ca98a10
--- /dev/null
+++ b/test/files/neg/t5691.check
@@ -0,0 +1,24 @@
+t5691.scala:7: warning: type parameter D defined in method foobar shadows trait D defined in class B. You may want to rename your type parameter, or possibly remove it.
+  def foobar[D](in: D) = in.toString
+             ^
+t5691.scala:10: warning: type parameter D defined in type MySeq shadows trait D defined in class B. You may want to rename your type parameter, or possibly remove it.
+  type MySeq[D] = Seq[D]
+             ^
+t5691.scala:15: warning: type parameter T defined in method bar shadows type T defined in class Foo. You may want to rename your type parameter, or possibly remove it.
+    def bar[T](w: T) = w.toString
+            ^
+t5691.scala:13: warning: type parameter T defined in class Foo shadows type T defined in class B. You may want to rename your type parameter, or possibly remove it.
+  class Foo[T](t: T) {
+            ^
+t5691.scala:19: warning: type parameter List defined in type M shadows type List defined in package object scala. You may want to rename your type parameter, or possibly remove it.
+  class C[M[List[_]]]
+            ^
+t5691.scala:20: warning: type parameter List defined in type M shadows type List defined in package object scala. You may want to rename your type parameter, or possibly remove it.
+  type E[M[List[_]]] = Int
+           ^
+t5691.scala:21: warning: type parameter List defined in type M shadows type List defined in package object scala. You may want to rename your type parameter, or possibly remove it.
+  def foo[N[M[List[_]]]] = ???
+              ^
+error: No warnings can be incurred under -Xfatal-warnings.
+7 warnings found
+one error found
diff --git a/test/files/neg/t5691.flags b/test/files/neg/t5691.flags
new file mode 100644
index 0000000000..0e09b8575b
--- /dev/null
+++ b/test/files/neg/t5691.flags
@@ -0,0 +1 @@
+-Xlint:type-parameter-shadow -language:higherKinds -Xfatal-warnings
diff --git a/test/files/neg/t5691.scala b/test/files/neg/t5691.scala
new file mode 100644
index 0000000000..e6a9bdc16a
--- /dev/null
+++ b/test/files/neg/t5691.scala
@@ -0,0 +1,27 @@
+class B {
+
+  type T = Int
+  trait D
+
+  // method parameter shadows some other type
+  def foobar[D](in: D) = in.toString
+
+  // type member's parameter shadows some other type
+  type MySeq[D] = Seq[D]
+
+  // class parameter shadows some other type
+  class Foo[T](t: T) {
+    // a type parameter shadows another type parameter
+    def bar[T](w: T) = w.toString
+  }
+
+  // even deeply nested...
+  class C[M[List[_]]]
+  type E[M[List[_]]] = Int
+  def foo[N[M[List[_]]]] = ???
+
+  // ...but not between type parameters in the same list
+  class F[A, M[L[A]]]         // no warning!
+  type G[A, M[L[A]]] = Int    // no warning!
+  def bar[A, N[M[L[A]]]] = ??? // no warning!
+}
diff --git a/test/files/neg/t6675b.scala b/test/files/neg/t6675b.scala
index c86c9c3955..da27e1b91f 100644
--- a/test/files/neg/t6675b.scala
+++ b/test/files/neg/t6675b.scala
@@ -13,7 +13,7 @@ object NativelyTwo {
 }
 
 
-class A {
+class E {
   def f1 = (Left((0, 0)): Either[(Int, Int), (Int, Int)]) match { case LeftOrRight(a) => a  }          // warn
   def f2 = (Left((0, 0)): Either[(Int, Int), (Int, Int)]) match { case LeftOrRight((a, b)) => a  }     // no warn
   def f3 = (Left((0, 0)): Either[(Int, Int), (Int, Int)]) match { case LeftOrRight((a, b, c)) => a  }  // fail