Merge pull request #14088 from dotty-staging/fix-#13947

Add Reflect TypeRepr.typeArgs

Author: anatoliykmetyuk

compiler/src/scala/quoted/runtime/impl/QuotesImpl.scala

@@ -1749,6 +1749,10 @@ class QuotesImpl private (using val ctx: Context) extends Quotes, QuoteUnpickler
           dotc.core.Types.decorateTypeApplications(self).appliedTo(targs)
         def substituteTypes(from: List[Symbol], to: List[TypeRepr]): TypeRepr =
           self.subst(from, to)
+
+        def typeArgs: List[TypeRepr] = self match
+          case AppliedType(_, args) => args
+          case _ => List.empty
       end extension
     end TypeReprMethods
 
@@ -2480,6 +2484,7 @@ class QuotesImpl private (using val ctx: Context) extends Quotes, QuoteUnpickler
 
         def name: String = self.denot.name.toString
         def fullName: String = self.denot.fullName.toString
+
         def pos: Option[Position] =
           if self.exists then Some(self.sourcePos) else None
 

library/src/scala/quoted/Quotes.scala

@@ -2571,6 +2571,9 @@ trait Quotes { self: runtime.QuoteUnpickler & runtime.QuoteMatching =>
         @experimental
         def substituteTypes(from: List[Symbol], to: List[TypeRepr]): TypeRepr
 
+        /** The applied type arguments (empty if there is no such arguments) */
+        @experimental
+        def typeArgs: List[TypeRepr]
       end extension
     }
 

project/MiMaFilters.scala

@@ -9,6 +9,8 @@ object MiMaFilters {
     ProblemFilters.exclude[DirectMissingMethodProblem]("scala.runtime.Tuples.append"),
     ProblemFilters.exclude[ReversedMissingMethodProblem]("scala.quoted.Quotes#reflectModule#TypeReprMethods.substituteTypes"),
     ProblemFilters.exclude[DirectMissingMethodProblem]("scala.quoted.Quotes#reflectModule#TypeReprMethods.substituteTypes"),
+    ProblemFilters.exclude[ReversedMissingMethodProblem]("scala.quoted.Quotes#reflectModule#TypeReprMethods.typeArgs"),
+    ProblemFilters.exclude[DirectMissingMethodProblem]("scala.quoted.Quotes#reflectModule#TypeReprMethods.typeArgs"),
     ProblemFilters.exclude[MissingClassProblem]("scala.compiletime.ops.double"),
     ProblemFilters.exclude[MissingClassProblem]("scala.compiletime.ops.double$"),
     ProblemFilters.exclude[MissingClassProblem]("scala.compiletime.ops.float"),

tests/run-macros/i13947.check

@@ -0,0 +1,3 @@
+[]
+[scala.Predef.String]
+[scala.Int, scala.Float, scala.Long]

tests/run-macros/i13947/Macro_1.scala

@@ -0,0 +1,12 @@
+import scala.quoted.*
+
+inline def printTypeParams[A]: Unit = ${ printTypeParamsImpl[A] }
+
+def printTypeParamsImpl[A: Type](using Quotes): Expr[Unit] = {
+  import quotes.reflect.*
+
+  val targs: List[TypeRepr] = TypeRepr.of[A].typeArgs
+  val debug = targs.map(_.show).mkString("[", ", ", "]")
+
+  '{ println(${Expr(debug)}) }
+}

tests/run-macros/i13947/Test_2.scala

@@ -0,0 +1,4 @@
+@main def Test: Unit =
+  printTypeParams[scala.util.Random]
+  printTypeParams[Option[String]]
+  printTypeParams[Function2[Int, Float, Long]]