address review comments

Author: bishabosha

compiler/src/dotty/tools/dotc/typer/Synthesizer.scala

@@ -290,14 +290,14 @@ class Synthesizer(typer: Typer)(using @constructorOnly c: Context):
         case (Singleton(src1, _), Singleton(src2, _)) => src1 eq src2
         case (_: ClassSymbol, _: Singleton) => false
 
-    def debug(using Context): String = this match
+    def show(using Context): String = this match
       case ClassSymbol(cls) => i"$cls"
       case Singleton(src, _) => i"$src"
 
-  object MirrorSource:
+  private[Synthesizer] object MirrorSource:
 
     /** Reduces a mirroredType to either its most specific ClassSymbol,
-     *  or a TermRef to a singleton value, these are
+     *  or a TermRef to a singleton value. These are
      *  the base elements required to generate a mirror.
      */
     def reduce(mirroredType: Type)(using Context): Either[String, MirrorSource] = mirroredType match
@@ -341,7 +341,7 @@ class Synthesizer(typer: Typer)(using @constructorOnly c: Context):
           res <- locally {
             if lsrc.isSub(rsrc) then Right(lsrc)
             else if rsrc.isSub(lsrc) then Right(rsrc)
-            else Left(i"its subpart `$tp` is an intersection of unrelated symbols ${lsrc.debug} and ${rsrc.debug}.")
+            else Left(i"its subpart `$tp` is an intersection of unrelated definitions ${lsrc.show} and ${rsrc.show}.")
           }
         yield
           res

tests/neg/mirror-synthesis-errors-b.check

@@ -1,40 +1,40 @@
 -- Error: tests/neg/mirror-synthesis-errors-b.scala:21:56 --------------------------------------------------------------
 21 |val testA = summon[Mirror.ProductOf[Cns[Int] & Sm[Int]]] // error: unreleated
    |                                                        ^
-   |No given instance of type deriving.Mirror.ProductOf[Cns[Int] & Sm[Int]] was found for parameter x of method summon in object Predef. Failed to synthesize an instance of type deriving.Mirror.ProductOf[Cns[Int] & Sm[Int]]: type `Cns[Int] & Sm[Int]` is not a generic product because its subpart `Cns[Int] & Sm[Int]` is an intersection of unrelated symbols class Cns and class Sm.
+   |No given instance of type deriving.Mirror.ProductOf[Cns[Int] & Sm[Int]] was found for parameter x of method summon in object Predef. Failed to synthesize an instance of type deriving.Mirror.ProductOf[Cns[Int] & Sm[Int]]: type `Cns[Int] & Sm[Int]` is not a generic product because its subpart `Cns[Int] & Sm[Int]` is an intersection of unrelated definitions class Cns and class Sm.
 -- Error: tests/neg/mirror-synthesis-errors-b.scala:22:56 --------------------------------------------------------------
 22 |val testB = summon[Mirror.ProductOf[Sm[Int] & Cns[Int]]] // error: unreleated
    |                                                        ^
-   |No given instance of type deriving.Mirror.ProductOf[Sm[Int] & Cns[Int]] was found for parameter x of method summon in object Predef. Failed to synthesize an instance of type deriving.Mirror.ProductOf[Sm[Int] & Cns[Int]]: type `Sm[Int] & Cns[Int]` is not a generic product because its subpart `Sm[Int] & Cns[Int]` is an intersection of unrelated symbols class Sm and class Cns.
+   |No given instance of type deriving.Mirror.ProductOf[Sm[Int] & Cns[Int]] was found for parameter x of method summon in object Predef. Failed to synthesize an instance of type deriving.Mirror.ProductOf[Sm[Int] & Cns[Int]]: type `Sm[Int] & Cns[Int]` is not a generic product because its subpart `Sm[Int] & Cns[Int]` is an intersection of unrelated definitions class Sm and class Cns.
 -- Error: tests/neg/mirror-synthesis-errors-b.scala:23:49 --------------------------------------------------------------
 23 |val testC = summon[Mirror.Of[Cns[Int] & Sm[Int]]] // error: unreleated
    |                                                 ^
    |No given instance of type deriving.Mirror.Of[Cns[Int] & Sm[Int]] was found for parameter x of method summon in object Predef. Failed to synthesize an instance of type deriving.Mirror.Of[Cns[Int] & Sm[Int]]: 
-   |	* type `Cns[Int] & Sm[Int]` is not a generic product because its subpart `Cns[Int] & Sm[Int]` is an intersection of unrelated symbols class Cns and class Sm.
-   |	* type `Cns[Int] & Sm[Int]` is not a generic sum because its subpart `Cns[Int] & Sm[Int]` is an intersection of unrelated symbols class Cns and class Sm.
+   |	* type `Cns[Int] & Sm[Int]` is not a generic product because its subpart `Cns[Int] & Sm[Int]` is an intersection of unrelated definitions class Cns and class Sm.
+   |	* type `Cns[Int] & Sm[Int]` is not a generic sum because its subpart `Cns[Int] & Sm[Int]` is an intersection of unrelated definitions class Cns and class Sm.
 -- Error: tests/neg/mirror-synthesis-errors-b.scala:24:49 --------------------------------------------------------------
 24 |val testD = summon[Mirror.Of[Sm[Int] & Cns[Int]]] // error: unreleated
    |                                                 ^
    |No given instance of type deriving.Mirror.Of[Sm[Int] & Cns[Int]] was found for parameter x of method summon in object Predef. Failed to synthesize an instance of type deriving.Mirror.Of[Sm[Int] & Cns[Int]]: 
-   |	* type `Sm[Int] & Cns[Int]` is not a generic product because its subpart `Sm[Int] & Cns[Int]` is an intersection of unrelated symbols class Sm and class Cns.
-   |	* type `Sm[Int] & Cns[Int]` is not a generic sum because its subpart `Sm[Int] & Cns[Int]` is an intersection of unrelated symbols class Sm and class Cns.
+   |	* type `Sm[Int] & Cns[Int]` is not a generic product because its subpart `Sm[Int] & Cns[Int]` is an intersection of unrelated definitions class Sm and class Cns.
+   |	* type `Sm[Int] & Cns[Int]` is not a generic sum because its subpart `Sm[Int] & Cns[Int]` is an intersection of unrelated definitions class Sm and class Cns.
 -- Error: tests/neg/mirror-synthesis-errors-b.scala:25:55 --------------------------------------------------------------
 25 |val testE = summon[Mirror.ProductOf[Sm[Int] & Nn.type]] // error: unreleated
    |                                                       ^
-   |No given instance of type deriving.Mirror.ProductOf[Sm[Int] & Nn.type] was found for parameter x of method summon in object Predef. Failed to synthesize an instance of type deriving.Mirror.ProductOf[Sm[Int] & Nn.type]: type `Sm[Int] & Nn.type` is not a generic product because its subpart `Sm[Int] & Nn.type` is an intersection of unrelated symbols class Sm and object Nn.
+   |No given instance of type deriving.Mirror.ProductOf[Sm[Int] & Nn.type] was found for parameter x of method summon in object Predef. Failed to synthesize an instance of type deriving.Mirror.ProductOf[Sm[Int] & Nn.type]: type `Sm[Int] & Nn.type` is not a generic product because its subpart `Sm[Int] & Nn.type` is an intersection of unrelated definitions class Sm and object Nn.
 -- Error: tests/neg/mirror-synthesis-errors-b.scala:26:55 --------------------------------------------------------------
 26 |val testF = summon[Mirror.ProductOf[Nn.type & Sm[Int]]] // error: unreleated
    |                                                       ^
-   |No given instance of type deriving.Mirror.ProductOf[Nn.type & Sm[Int]] was found for parameter x of method summon in object Predef. Failed to synthesize an instance of type deriving.Mirror.ProductOf[Nn.type & Sm[Int]]: type `Nn.type & Sm[Int]` is not a generic product because its subpart `Nn.type & Sm[Int]` is an intersection of unrelated symbols object Nn and class Sm.
+   |No given instance of type deriving.Mirror.ProductOf[Nn.type & Sm[Int]] was found for parameter x of method summon in object Predef. Failed to synthesize an instance of type deriving.Mirror.ProductOf[Nn.type & Sm[Int]]: type `Nn.type & Sm[Int]` is not a generic product because its subpart `Nn.type & Sm[Int]` is an intersection of unrelated definitions object Nn and class Sm.
 -- Error: tests/neg/mirror-synthesis-errors-b.scala:27:54 --------------------------------------------------------------
 27 |val testG = summon[Mirror.Of[Foo.A.type & Foo.B.type]] // error: unreleated
    |                                                      ^
    |No given instance of type deriving.Mirror.Of[(Foo.A : Foo) & (Foo.B : Foo)] was found for parameter x of method summon in object Predef. Failed to synthesize an instance of type deriving.Mirror.Of[(Foo.A : Foo) & (Foo.B : Foo)]: 
-   |	* type `(Foo.A : Foo) & (Foo.B : Foo)` is not a generic product because its subpart `(Foo.A : Foo) & (Foo.B : Foo)` is an intersection of unrelated symbols value A and value B.
-   |	* type `(Foo.A : Foo) & (Foo.B : Foo)` is not a generic sum because its subpart `(Foo.A : Foo) & (Foo.B : Foo)` is an intersection of unrelated symbols value A and value B.
+   |	* type `(Foo.A : Foo) & (Foo.B : Foo)` is not a generic product because its subpart `(Foo.A : Foo) & (Foo.B : Foo)` is an intersection of unrelated definitions value A and value B.
+   |	* type `(Foo.A : Foo) & (Foo.B : Foo)` is not a generic sum because its subpart `(Foo.A : Foo) & (Foo.B : Foo)` is an intersection of unrelated definitions value A and value B.
 -- Error: tests/neg/mirror-synthesis-errors-b.scala:28:54 --------------------------------------------------------------
 28 |val testH = summon[Mirror.Of[Foo.B.type & Foo.A.type]] // error: unreleated
    |                                                      ^
    |No given instance of type deriving.Mirror.Of[(Foo.B : Foo) & (Foo.A : Foo)] was found for parameter x of method summon in object Predef. Failed to synthesize an instance of type deriving.Mirror.Of[(Foo.B : Foo) & (Foo.A : Foo)]: 
-   |	* type `(Foo.B : Foo) & (Foo.A : Foo)` is not a generic product because its subpart `(Foo.B : Foo) & (Foo.A : Foo)` is an intersection of unrelated symbols value B and value A.
-   |	* type `(Foo.B : Foo) & (Foo.A : Foo)` is not a generic sum because its subpart `(Foo.B : Foo) & (Foo.A : Foo)` is an intersection of unrelated symbols value B and value A.
+   |	* type `(Foo.B : Foo) & (Foo.A : Foo)` is not a generic product because its subpart `(Foo.B : Foo) & (Foo.A : Foo)` is an intersection of unrelated definitions value B and value A.
+   |	* type `(Foo.B : Foo) & (Foo.A : Foo)` is not a generic sum because its subpart `(Foo.B : Foo) & (Foo.A : Foo)` is an intersection of unrelated definitions value B and value A.

tests/run/i15234.scala

@@ -13,6 +13,7 @@ package app {
   val Bar: lib.Bar.type = lib.Bar
 }
 
+
 @main def Test =
   assert(summon[Mirror.Of[scala.Nil.type]].fromProduct(EmptyTuple) == Nil) // alias scala 2 defined
   assert(summon[Mirror.Of[lib.Foo.A.type]].fromProduct(EmptyTuple) == lib.Foo.A) // real mirror