Address review comments

Author: bracevac

compiler/src/dotty/tools/dotc/parsing/Parsers.scala

@@ -1593,7 +1593,6 @@ object Parsers {
     }
 
     /** CaptureRef  ::=  { SimpleRef `.` } SimpleRef [`*`] [`.` `rd`] -- under captureChecking
-     *                |  [ { SimpleRef `.` } SimpleRef `.` ] id
      */
     def captureRef(): Tree =
 
@@ -2183,7 +2182,7 @@ object Parsers {
      *    NameAndType       ::=  id ‘:’ Type
      */
     def argTypes(namedOK: Boolean, wildOK: Boolean, tupleOK: Boolean): List[Tree] =
-      inline def wildCardCheck(inline gen: Tree): Tree =
+      def wildCardCheck(gen: Tree): Tree =
         val t = gen
         if wildOK then t else rejectWildcardType(t)
 
@@ -2210,7 +2209,7 @@ object Parsers {
       if namedOK && (isIdent && in.lookahead.token == EQUALS) then
         commaSeparated(() => namedTypeArg())
       else if tupleOK && isIdent && in.lookahead.isColon && sourceVersion.enablesNamedTuples then
-        commaSeparated(() => nameAndType()) // TODO: can capture-set variables occur here?
+        commaSeparated(() => nameAndType())
       else
         commaSeparated(() => typeArg())
     end argTypes
@@ -2279,9 +2278,9 @@ object Parsers {
         TypeBoundsTree(bound(SUPERTYPE), bound(SUBTYPE))
 
     private def bound(tok: Int): Tree =
-      if (in.token == tok) then
+      if in.token == tok then
         in.nextToken()
-        if Feature.ccEnabled && (in.token == LBRACE && !isDclIntroNext) then
+        if Feature.ccEnabled && in.token == LBRACE && !isDclIntroNext then
           capsBound(captureSet(), isLowerBound = tok == SUPERTYPE)
         else toplevelTyp()
       else EmptyTree
@@ -2290,7 +2289,7 @@ object Parsers {
       if isLowerBound && refs.isEmpty then // lower bounds with empty capture sets become a pure CapSet
         Select(scalaDot(nme.caps), tpnme.CapSet)
       else
-        makeRetaining(Select(scalaDot(nme.caps), tpnme.CapSet), refs, tpnme.retains)
+        concreteCapsType(refs)
 
     /** TypeAndCtxBounds  ::=  TypeBounds [`:` ContextBounds]
      */

docs/_docs/internals/syntax.md

@@ -242,7 +242,6 @@ NamesAndTypes     ::=  NameAndType {‘,’ NameAndType}
 NameAndType       ::=  id ':' Type
 CaptureSet        ::=  ‘{’ CaptureRef {‘,’ CaptureRef} ‘}’                      -- under captureChecking
 CaptureRef        ::=  { SimpleRef ‘.’ } SimpleRef [‘*’] [‘.’ ‘rd’]             -- under captureChecking
-                    |  [ { SimpleRef ‘.’ } SimpleRef ‘.’ ] id                   -- under captureChecking
 ```
 
 ### Expressions

tests/neg-custom-args/captures/capset-bound.scala

@@ -1,3 +1,4 @@
+import language.experimental.captureChecking
 import caps.*
 
 class IO
@@ -6,6 +7,7 @@ case class File(io: IO^)
 
 def test(io1: IO^, io2: IO^) =
   def f[C^ >: {io1}](file: File^{C}) = ???
+  def g[C >: {io1}](file: File^{C}) = ???
   val f1: File^{io1} = ???
   val f2: File^{io2} = ???
   val f3: File^{io1, io2} = ???
@@ -15,4 +17,11 @@ def test(io1: IO^, io2: IO^) =
   f[{io2}](f2) // error
   f[{io1, io2}](f1)
   f[{io1, io2}](f2)
-  f[{io1, io2}](f3)
+  f[{io1, io2}](f3)
+  g[{io1}](f1)
+  g[{io1}](f2) // error
+  g[{io1}](f3) // error
+  g[{io2}](f2) // error
+  g[{io1, io2}](f1)
+  g[{io1, io2}](f2)
+  g[{io1, io2}](f3)

tests/neg-custom-args/captures/capset-members-nohat.scala

@@ -0,0 +1,30 @@
+import language.experimental.captureChecking
+import caps.*
+
+trait Abstract[X^]:
+  type C >: {X}
+  // Don't test the return type using Unit, because it is a pure type.
+  def boom(): AnyRef^{C}
+
+class Concrete extends Abstract[{}]:
+  type C^ = {}
+  // TODO: Why do we get error without the return type here?
+  def boom(): AnyRef = new Object
+
+class Concrete2 extends Abstract[{}]:
+  type C^ = {}
+  def boom(): AnyRef^ = new Object // error
+
+class Concrete3 extends Abstract[{}]:
+  def boom(): AnyRef = new Object
+
+class Concrete4(a: AnyRef^) extends Abstract[{a}]:
+  type C^ = {} // error
+  def boom(): AnyRef^{a} = a // error
+
+class Concrete5(a: AnyRef^, b: AnyRef^) extends Abstract[{a}]:
+  type C^ = {a}
+  def boom(): AnyRef^{b} = b // error
+
+class Concrete6(a: AnyRef^, b: AnyRef^) extends Abstract[{a}]:
+  def boom(): AnyRef^{b} = b // error