[SemanticDB] fix regression in type apply synthetics (#16031)

This PR fixes the regressions in SemanticDB's TypeApply synthetics
introduced by #15877

-
e835dc0
-
097b179
-
097b179

Previously, we relies on `Scala2` flag for filtering out some
synthetics, which isn't reliable for SemanticDB (that's why the capture
checking made a change in how the compiler put flags to symbols and the
regression occurred).
This PR fixes the regression by re-implements TypeApply synthetics
without using `Scala2` flag.

(also fix scalameta/metals#4372)

Probably, it makes more sense to compare the `metac.expect`'s diff from
53e1adc which was something before the
regression.

<details>
<summary>diff from 53e1adc</summary>

`git diff 53e1adc HEAD
tests/semanticdb/metac.expect`

```diff
diff --git a/tests/semanticdb/metac.expect b/tests/semanticdb/metac.expect
index 5e20650..2c7f720 100644
--- a/tests/semanticdb/metac.expect
+++ b/tests/semanticdb/metac.expect
@@ -50,7 +50,7 @@ Text => empty
 Language => Scala
 Symbols => 60 entries
 Occurrences => 132 entries
-Synthetics => 4 entries
+Synthetics => 3 entries
 
 Symbols:
 advanced/C# => class C [typeparam T ] extends Object { self: C[T] => +3 decls }
@@ -252,7 +252,6 @@ Synthetics:
 [27:12..27:16):s.s1 => reflectiveSelectable(*)
 [29:12..29:16):s.s2 => reflectiveSelectable(*)
 [31:12..31:16):s.s3 => reflectiveSelectable(*)
-[47:19..47:24):foo.a => *[foo.A]
 
 expect/Annotations.scala
 ------------------------
@@ -264,7 +263,6 @@ Text => empty
 Language => Scala
 Symbols => 23 entries
 Occurrences => 52 entries
-Synthetics => 2 entries
 
 Symbols:
 annot/Alias. => final object Alias extends Object { self: Alias.type => +2 decls }
@@ -345,10 +343,6 @@ Occurrences:
 [39:11..39:26): ClassAnnotation -> com/javacp/annot/ClassAnnotation#
 [39:28..39:33): param -> scala/annotation/meta/param#
 
-Synthetics:
-[25:2..25:20):@throws[Exception] => *[Exception]
-[25:2..25:20):@throws[Exception] => *[Exception]
-
 expect/Anonymous.scala
 ----------------------
 
@@ -896,7 +890,7 @@ Text => empty
 Language => Scala
 Symbols => 181 entries
 Occurrences => 148 entries
-Synthetics => 10 entries
+Synthetics => 6 entries
 
 Symbols:
 _empty_/Enums. => final object Enums extends Object { self: Enums.type => +30 decls }
@@ -1232,16 +1226,12 @@ Occurrences:
 [68:25..68:31): Planet -> _empty_/Enums.Planet#
 
 Synthetics:
-[46:28..46:35):C <:< C => *[C, C]
-[49:27..49:31):Refl => *.apply[T]
 [52:9..52:13):Refl => *.unapply[Option[B]]
-[52:19..52:30):opt.flatMap => *[B]
 [52:31..52:50):identity[Option[B]] => *[Function1[A, Option[B]]]
 [54:14..54:18):Some => *.apply[Some[Int]]
 [54:14..54:34):Some(Some(1)).unwrap => *(given_<:<_T_T[Option[Int]])
 [54:19..54:23):Some => *.apply[Int]
 [54:28..54:34):unwrap => *[Some[Int], Int]
-[56:52..56:64):Enum[Planet] => *[Planet]
 
 expect/EtaExpansion.scala
 -------------------------
@@ -3165,7 +3155,7 @@ Text => empty
 Language => Scala
 Symbols => 52 entries
 Occurrences => 132 entries
-Synthetics => 36 entries
+Synthetics => 39 entries
 
 Symbols:
 example/Synthetic# => class Synthetic extends Object { self: Synthetic => +23 decls }
@@ -3361,12 +3351,15 @@ Synthetics:
 [6:2..6:18):Array.empty[Int] => intArrayOps(*)
 [7:2..7:8):"fooo" => augmentString(*)
 [10:13..10:24):"name:(.*)" => augmentString(*)
+[11:8..11:11):#:: => *.unapply[Int]
 [11:17..11:25):LazyList => *.apply[Int]
 [13:4..13:28):#:: 2 #:: LazyList.empty => *[Int]
 [13:8..13:28):2 #:: LazyList.empty => toDeferrer[Int](*)
 [13:10..13:28):#:: LazyList.empty => *[Int]
 [13:14..13:28):LazyList.empty => toDeferrer[Nothing](*)
 [13:14..13:28):LazyList.empty => *[Nothing]
+[15:9..15:12):#:: => *.unapply[Int]
+[15:16..15:19):#:: => *.unapply[Int]
 [15:25..15:33):LazyList => *.apply[Int]
 [17:14..17:38):#:: 2 #:: LazyList.empty => *[Int]
 [17:18..17:38):2 #:: LazyList.empty => toDeferrer[Int](*)
@@ -3471,7 +3464,7 @@ Text => empty
 Language => Scala
 Symbols => 22 entries
 Occurrences => 46 entries
-Synthetics => 7 entries
+Synthetics => 11 entries
 
 Symbols:
 example/ValPattern# => class ValPattern extends Object { self: ValPattern => +14 decls }
@@ -3546,12 +3539,16 @@ Occurrences:
 [40:10..40:18): rightVar -> local4
 
 Synthetics:
+[5:6..5:10):Some => *.unapply[Int]
 [6:4..6:8):Some => *.apply[Int]
 [8:6..8:10):List => *.unapplySeq[Nothing]
 [8:11..8:15):Some => *.unapply[Nothing]
+[11:6..11:10):Some => *.unapply[Int]
 [12:4..12:8):Some => *.apply[Int]
 [25:4..25:11):locally => *[Unit]
+[27:10..27:14):Some => *.unapply[Int]
 [28:8..28:12):Some => *.apply[Int]
+[31:10..31:14):Some => *.unapply[Int]
 [32:8..32:12):Some => *.apply[Int]
 
 expect/Vals.scala
@@ -4264,7 +4261,6 @@ Text => empty
 Language => Scala
 Symbols => 36 entries
 Occurrences => 46 entries
-Synthetics => 3 entries
 
 Symbols:
 local0 => type N$1  <: Nat
@@ -4352,11 +4348,6 @@ Occurrences:
 [23:35..23:39): Zero -> recursion/Nats.Zero.
 [23:40..23:42): ++ -> recursion/Nats.Nat#`++`().
 
-Synthetics:
-[5:50..5:54):Succ => *.apply[Nat.this.type]
-[10:13..10:17):Succ => *.unapply[N$1]
-[20:11..20:15):Succ => *.unapply[N$2]
-
 expect/semanticdb-Definitions.scala
 -----------------------------------
 
```

</details>

Author: bishabosha

compiler/src/dotty/tools/dotc/semanticdb/Scala3.scala

@@ -222,6 +222,12 @@ object Scala3:
           case NameKinds.AnyNumberedName(nme.EMPTY, _) => true
           case _                                       => false
         }
+
+      def isDynamic(using Context): Boolean =
+        name == nme.applyDynamic ||
+        name == nme.selectDynamic ||
+        name == nme.updateDynamic ||
+        name == nme.applyDynamicNamed
   end NameOps
 
   given SymbolOps: AnyRef with

compiler/src/dotty/tools/dotc/semanticdb/SyntheticsExtractor.scala

@@ -4,6 +4,7 @@ import dotty.tools.dotc.ast.tpd._
 import dotty.tools.dotc.core.Contexts._
 import dotty.tools.dotc.core.Flags._
 import dotty.tools.dotc.core.StdNames.nme
+import dotty.tools.dotc.core.NameKinds
 import dotty.tools.dotc.{semanticdb => s}
 
 
@@ -26,8 +27,21 @@ class SyntheticsExtractor:
       tree match
         case tree: TypeApply
           if tree.span.isSynthetic &&
-            tree.args.forall(arg => !arg.symbol.is(Scala2x)) &&
-            !tree.span.isZeroExtent =>
+            tree.args.forall(arg => !arg.symbol.isDefinedInSource) &&
+            !tree.span.isZeroExtent &&
+            (tree.fun match {
+              // for `Bar[Int]` of `class Foo extends Bar[Int]`
+              // we'll have `TypeTree(Select(New(AppliedTypeTree(...))), List(Int))`
+              // in this case, don't register `*[Int]` to synthetics as we already have `[Int]` in source.
+              case Select(New(AppliedTypeTree(_, _)), _) => false
+
+              // for `new SomeJavaClass[Int]()`
+              // there will be a synthesized default getter
+              // in addition to the source derived one.
+              case Select(_, name) if name.is(NameKinds.DefaultGetterName) => false
+              case Select(fun, _) if fun.symbol.name.isDynamic => false
+              case _ => true
+            }) =>
           visited.add(tree)
           val fnTree = tree.fun match
             // Something like `List.apply[Int](1,2,3)`