Merge pull request #13166 from dotty-staging/fix-#12392

Add reflect TypeRepr.substituteTypes

Author: anatoliykmetyuk

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

@@ -1747,6 +1747,8 @@ class QuotesImpl private (using val ctx: Context) extends Quotes, QuoteUnpickler
           dotc.core.Types.decorateTypeApplications(self).appliedTo(targ)
         def appliedTo(targs: List[TypeRepr]): TypeRepr =
           dotc.core.Types.decorateTypeApplications(self).appliedTo(targs)
+        def substituteTypes(from: List[Symbol], to: List[TypeRepr]): TypeRepr =
+          self.subst(from, to)
       end extension
     end TypeReprMethods
 

compiler/test/dotty/tools/repl/TabcompleteTests.scala

@@ -134,7 +134,7 @@ class TabcompleteTests extends ReplTest {
   }
 
   @Test def i12600 = fromInitialState { implicit s =>
-    assertEquals(List("select", "show", "simplified"),
+    assertEquals(List("select", "show", "simplified", "substituteTypes"),
       tabComplete("import quoted.* ; def fooImpl(using Quotes): Expr[Int] = { import quotes.reflect.* ; TypeRepr.of[Int].s"))
   }
 

library/src/scala/quoted/Quotes.scala

@@ -2565,6 +2565,12 @@ trait Quotes { self: runtime.QuoteUnpickler & runtime.QuoteMatching =>
         /** The current type applied to given type arguments: `this[targ0, ..., targN]` */
         def appliedTo(targs: List[TypeRepr]): TypeRepr
 
+        /** Substitute all types that refer in their symbol attribute to
+         *  one of the symbols in `from` by the corresponding types in `to`.
+         */
+        @experimental
+        def substituteTypes(from: List[Symbol], to: List[TypeRepr]): TypeRepr
+
       end extension
     }
 

project/MiMaFilters.scala

@@ -1,12 +1,13 @@
 
 import com.typesafe.tools.mima.core._
-import com.typesafe.tools.mima.core.ProblemFilters._
 
 object MiMaFilters {
   val Library: Seq[ProblemFilter] = Seq(
     // Experimental APIs that can be added in 3.2.0
     ProblemFilters.exclude[DirectMissingMethodProblem]("scala.runtime.Tuples.init"),
     ProblemFilters.exclude[DirectMissingMethodProblem]("scala.runtime.Tuples.last"),
-    ProblemFilters.exclude[DirectMissingMethodProblem]("scala.runtime.Tuples.append")
+    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"),
   )
 }

tests/run-macros/i12392.check

@@ -0,0 +1 @@
+scala.Option[scala.Predef.String] to scala.Option[scala.Int]

tests/run-macros/i12392/Macros_1.scala

@@ -0,0 +1,24 @@
+import scala.quoted.*
+
+inline def testSubst: Unit = ${ testSubstImpl }
+
+def testSubstImpl(using Quotes): Expr[Unit] = {
+  import quotes.reflect.*
+
+  val intTpe = TypeRepr.of[Int]
+  val strOptTpe = TypeRepr.of[Option[String]]
+
+  val tpeArgs: List[TypeRepr] = strOptTpe match {
+    case AppliedType(_, args) => args
+    case _                    => List.empty[TypeRepr]
+  }
+
+  val intOptTpe = strOptTpe.substituteTypes(
+    tpeArgs.map(_.typeSymbol), List(intTpe))
+
+  val repr = s"${strOptTpe.show} to ${intOptTpe.show}"
+
+  '{
+    println(${Expr(repr)})
+  }
+}

tests/run-macros/i12392/Test_2.scala

@@ -0,0 +1 @@
+@main def Test = testSubst