Merge pull request #4887 from dotty-staging/add-tasty-reflect-subtype-check

Add <:< and =:= to testy reflect Type

Author: nicolasstucki

compiler/src/dotty/tools/dotc/tastyreflect/TastyImpl.scala

@@ -769,6 +769,12 @@ class TastyImpl(val rootContext: Contexts.Context) extends scala.tasty.Tasty { s
   // ----- Types ----------------------------------------------------
 
   type Type = Types.Type
+
+  def TypeDeco(tpe: Type): TypeAPI = new TypeAPI {
+    def =:=(other: Type)(implicit ctx: Context): Boolean = tpe =:= other
+    def <:<(other: Type)(implicit ctx: Context): Boolean = tpe <:< other
+  }
+
   type RecursiveType = Types.RecType
   type LambdaType[ParamInfo <: TypeOrBounds] = Types.LambdaType { type PInfo = ParamInfo }
   type MethodType = Types.MethodType

library/src/scala/tasty/Tasty.scala

@@ -591,6 +591,12 @@ abstract class Tasty { tasty =>
 
   type Type <: TypeOrBounds
 
+  trait TypeAPI {
+    def =:=(other: Type)(implicit ctx: Context): Boolean
+    def <:<(other: Type)(implicit ctx: Context): Boolean
+  }
+  implicit def TypeDeco(tpe: Type): TypeAPI
+
   type RecursiveType <: Type
 
   type LambdaType[ParamInfo <: TypeOrBounds] <: Type

tests/run/tasty-subtyping.check

@@ -0,0 +1,24 @@
+true
+true
+true
+true
+true
+
+false
+false
+false
+false
+false
+
+true
+true
+true
+true
+true
+true
+
+false
+false
+false
+false
+false

tests/run/tasty-subtyping/quoted_1.scala

@@ -0,0 +1,24 @@
+import scala.quoted._
+
+import scala.tasty._
+
+object Macros {
+
+  transparent def isTypeEqual[T, U]: Boolean =
+    ~isTypeEqualImpl('[T], '[U])(TopLevelSplice.tastyContext) // FIXME infer TopLevelSplice.tastyContext within top level ~
+
+  transparent def isSubTypeOf[T, U]: Boolean =
+    ~isSubTypeOfImpl('[T], '[U])(TopLevelSplice.tastyContext) // FIXME infer TopLevelSplice.tastyContext within top level ~
+
+  def isTypeEqualImpl[T, U](t: Type[T], u: Type[U])(implicit tasty: Tasty): Expr[Boolean] = {
+    import tasty._
+    val isTypeEqual = t.toTasty.tpe =:= u.toTasty.tpe
+    isTypeEqual.toExpr
+  }
+
+  def isSubTypeOfImpl[T, U](t: Type[T], u: Type[U])(implicit tasty: Tasty): Expr[Boolean] = {
+    import tasty._
+    val isTypeEqual = t.toTasty.tpe <:< u.toTasty.tpe
+    isTypeEqual.toExpr
+  }
+}

tests/run/tasty-subtyping/quoted_2.scala

@@ -0,0 +1,41 @@
+
+import Macros._
+
+object Test {
+  type A
+  type B <: A
+
+  def main(args: Array[String]): Unit = {
+    // true
+    println(isTypeEqual[Int, Int])
+    println(isTypeEqual[String, String])
+    println(isTypeEqual[Test.type, Test.type])
+    println(isTypeEqual[2, 2])
+    println(isTypeEqual[A, A])
+    println()
+
+    // false
+    println(isTypeEqual[Int, Double])
+    println(isTypeEqual[String, Int])
+    println(isTypeEqual[Test.type, Macros.type])
+    println(isTypeEqual[2, 1])
+    println(isTypeEqual[A, B])
+    println()
+
+    // true
+    println(isSubTypeOf[Int, Int])
+    println(isSubTypeOf[String, Object])
+    println(isSubTypeOf[Int, AnyVal])
+    println(isSubTypeOf[AnyRef, Any])
+    println(isSubTypeOf[AnyVal, Any])
+    println(isSubTypeOf[B, A])
+    println()
+
+    // false
+    println(isSubTypeOf[Object, Int])
+    println(isSubTypeOf[AnyVal, Int])
+    println(isSubTypeOf[Any, AnyRef])
+    println(isSubTypeOf[Any, AnyVal])
+    println(isSubTypeOf[A, B])
+  }
+}