Update check files

Author: odersky

tests/neg/polymorphic-erased-functions-types.check

@@ -9,7 +9,10 @@
 4 |def t1b: [T] => (erased t: T) => Unit = [T] => (t: T) => () // error
   |                                        ^^^^^^^^^^^^^^^^^^^
   |                                        Found:    [T] => (t: T) => Unit
-  |                                        Required: [T] => (erased t: T) => Unit
+  |                                        Required: [T] => (erased t²: T) => Unit
+  |
+  |                                        where:    t  is a reference to a value parameter
+  |                                                  t² is a reference to a value parameter
   |
   | longer explanation available when compiling with `-explain`
 -- [E007] Type Mismatch Error: tests/neg/polymorphic-erased-functions-types.scala:6:36 ---------------------------------
@@ -23,6 +26,11 @@
 7 |def t2b: [T, U] => (t: T, erased u: U) => Unit = [T, U] => (t: T, u: U) => () // error
   |                                                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |                                                 Found:    [T, U] => (t: T, u: U) => Unit
-  |                                                 Required: [T, U] => (t: T, erased u: U) => Unit
+  |                                                 Required: [T, U] => (t²: T, erased u²: U) => Unit
+  |
+  |                                                 where:    t  is a reference to a value parameter
+  |                                                           t² is a reference to a value parameter
+  |                                                           u  is a reference to a value parameter
+  |                                                           u² is a reference to a value parameter
   |
   | longer explanation available when compiling with `-explain`

tests/neg/polymorphic-functions1.check

@@ -2,6 +2,9 @@
 1 |val f: [T] => (x: T) => x.type = [T] => (x: Int) => x // error
   |                                 ^^^^^^^^^^^^^^^^^^^^
   |                                 Found:    [T] => (x: Int) => x.type
-  |                                 Required: [T] => (x: T) => x.type
+  |                                 Required: [T] => (x²: T) => x².type
+  |
+  |                                 where:    x  is a reference to a value parameter
+  |                                           x² is a reference to a value parameter
   |
   | longer explanation available when compiling with `-explain`