From be868c281768a9bf44681fd3e123f21ec0baf1d1 Mon Sep 17 00:00:00 2001
From: "Frank S. Thomas" <frank@timepit.eu>
Date: Fri, 25 Sep 2020 21:36:30 +0200
Subject: [PATCH 1/9] Allow Int and Double literals as universal arguments

... for numeric predicates.
---
 .../timepit/refined/internal/WitnessAs.scala  | 69 ++++++++++++++----
 .../eu/timepit/refined/numeric.scala          |  9 ++-
 .../timepit/refined/internal/WitnessAs.scala  | 70 ++++++++++++++-----
 .../eu/timepit/refined/numeric.scala          |  9 ++-
 .../timepit/refined/NumericValidateSpec.scala | 29 ++++++--
 .../pureconfig/RefTypeConfigConvertSpec.scala |  4 +-
 .../shapeless/typeable/TypeableSpec.scala     |  2 +-
 7 files changed, 142 insertions(+), 50 deletions(-)

diff --git a/modules/core/shared/src/main/scala-3.0+/eu/timepit/refined/internal/WitnessAs.scala b/modules/core/shared/src/main/scala-3.0+/eu/timepit/refined/internal/WitnessAs.scala
index 29b4e9a19..4b940e71b 100644
--- a/modules/core/shared/src/main/scala-3.0+/eu/timepit/refined/internal/WitnessAs.scala
+++ b/modules/core/shared/src/main/scala-3.0+/eu/timepit/refined/internal/WitnessAs.scala
@@ -5,24 +5,10 @@ import shapeless.{Nat, Witness}
 /**
  * `WitnessAs[A, B]` provides the singleton value of type `A` in `fst`
  * and `fst` converted to type `B` in `snd`.
- *
- * The purpose of this type class is to write numeric type class
- * instances that work with both literal singleton types and
- * `shapeless.Nat`.
- *
- * Example: {{{
- * scala> import shapeless.nat._5
- *
- * scala> WitnessAs[5, Int]
- * res1: WitnessAs[5, Int] = WitnessAs(5,5)
- *
- * scala> WitnessAs[_5, Int]
- * res2: WitnessAs[_5, Int] = WitnessAs(Succ(),5)
- * }}}
  */
 final case class WitnessAs[A, B](fst: A, snd: B)
 
-object WitnessAs {
+object WitnessAs extends WitnessAs1 {
   def apply[A, B](implicit ev: WitnessAs[A, B]): WitnessAs[A, B] = ev
 
   implicit def natWitnessAs[B, A <: Nat](implicit
@@ -37,3 +23,56 @@ object WitnessAs {
   ): WitnessAs[A, B] =
     WitnessAs(wa.value, wa.value)
 }
+
+trait WitnessAs1 {
+  implicit def intWitnessAsByte[A <: Int](implicit
+      wa: ValueOf[A]
+  ): WitnessAs[A, Byte] =
+    if (wa.value >= Byte.MinValue.toInt && wa.value <= Byte.MaxValue.toInt)
+      WitnessAs(wa.value, wa.value.toByte)
+    else sys.error(s"WitnessAs: ${wa.value} is not in [Byte.MinValue, Byte.MaxValue]")
+
+  implicit def intWitnessAsShort[A <: Int](implicit
+      wa: ValueOf[A]
+  ): WitnessAs[A, Short] =
+    if (wa.value >= Short.MinValue.toInt && wa.value <= Short.MaxValue.toInt)
+      WitnessAs(wa.value, wa.value.toShort)
+    else sys.error(s"WitnessAs: ${wa.value} is not in [Short.MinValue, Short.MaxValue]")
+
+  implicit def intWitnessAsLong[A <: Int](implicit
+      wa: ValueOf[A]
+  ): WitnessAs[A, Long] =
+    WitnessAs(wa.value, wa.value.toLong)
+
+  implicit def intWitnessAsBigInt[A <: Int](implicit
+      wa: ValueOf[A]
+  ): WitnessAs[A, BigInt] =
+    WitnessAs(wa.value, BigInt(wa.value))
+
+  implicit def intWitnessAsFloat[A <: Int](implicit
+      wa: ValueOf[A]
+  ): WitnessAs[A, Float] =
+    WitnessAs(wa.value, wa.value.toFloat)
+
+  implicit def intWitnessAsDouble[A <: Int](implicit
+      wa: ValueOf[A]
+  ): WitnessAs[A, Double] =
+    WitnessAs(wa.value, wa.value.toDouble)
+
+  implicit def intWitnessAsBigDecimal[A <: Int](implicit
+      wa: ValueOf[A]
+  ): WitnessAs[A, BigDecimal] =
+    WitnessAs(wa.value, BigDecimal(wa.value))
+
+  implicit def doubleWitnessAsFloat[A <: Double](implicit
+      wa: ValueOf[A]
+  ): WitnessAs[A, Float] =
+    if (wa.value >= Float.MinValue.toDouble && wa.value <= Float.MaxValue.toDouble)
+      WitnessAs(wa.value, wa.value.toFloat)
+    else sys.error(s"WitnessAs: ${wa.value} is not in [Float.MinValue, Float.MaxValue]")
+
+  implicit def doubleWitnessAsBigDecimal[A <: Double](implicit
+      wa: ValueOf[A]
+  ): WitnessAs[A, BigDecimal] =
+    WitnessAs(wa.value, BigDecimal(wa.value))
+}
diff --git a/modules/core/shared/src/main/scala-3.0+/eu/timepit/refined/numeric.scala b/modules/core/shared/src/main/scala-3.0+/eu/timepit/refined/numeric.scala
index f6de5fcf8..9ac140823 100644
--- a/modules/core/shared/src/main/scala-3.0+/eu/timepit/refined/numeric.scala
+++ b/modules/core/shared/src/main/scala-3.0+/eu/timepit/refined/numeric.scala
@@ -6,7 +6,6 @@ import eu.timepit.refined.boolean.{And, Not}
 import eu.timepit.refined.internal.WitnessAs
 import eu.timepit.refined.numeric._
 import shapeless.Nat
-import shapeless.nat.{_0, _2}
 import shapeless.ops.nat.ToInt
 
 /**
@@ -51,25 +50,25 @@ object numeric extends NumericInference {
   type GreaterEqual[N] = Not[Less[N]]
 
   /** Predicate that checks if a numeric value is positive (> 0). */
-  type Positive = Greater[_0]
+  type Positive = Greater[0]
 
   /** Predicate that checks if a numeric value is zero or negative (<= 0). */
   type NonPositive = Not[Positive]
 
   /** Predicate that checks if a numeric value is negative (< 0). */
-  type Negative = Less[_0]
+  type Negative = Less[0]
 
   /** Predicate that checks if a numeric value is zero or positive (>= 0). */
   type NonNegative = Not[Negative]
 
   /** Predicate that checks if an integral value is evenly divisible by `N`. */
-  type Divisible[N] = Modulo[N, _0]
+  type Divisible[N] = Modulo[N, 0]
 
   /** Predicate that checks if an integral value is not evenly divisible by `N`. */
   type NonDivisible[N] = Not[Divisible[N]]
 
   /** Predicate that checks if an integral value is evenly divisible by 2. */
-  type Even = Divisible[_2]
+  type Even = Divisible[2]
 
   /** Predicate that checks if an integral value is not evenly divisible by 2. */
   type Odd = Not[Even]
diff --git a/modules/core/shared/src/main/scala-3.0-/eu/timepit/refined/internal/WitnessAs.scala b/modules/core/shared/src/main/scala-3.0-/eu/timepit/refined/internal/WitnessAs.scala
index 6a8308ea1..a673f3db4 100644
--- a/modules/core/shared/src/main/scala-3.0-/eu/timepit/refined/internal/WitnessAs.scala
+++ b/modules/core/shared/src/main/scala-3.0-/eu/timepit/refined/internal/WitnessAs.scala
@@ -6,25 +6,10 @@ import shapeless.ops.nat.ToInt
 /**
  * `WitnessAs[A, B]` provides the singleton value of type `A` in `fst`
  * and `fst` converted to type `B` in `snd`.
- *
- * The purpose of this type class is to write numeric type class
- * instances that work with both literal singleton types and
- * `shapeless.Nat`.
- *
- * Example: {{{
- * scala> import eu.timepit.refined.W
- *      | import shapeless.nat._5
- *
- * scala> WitnessAs[W.`5`.T, Int]
- * res1: WitnessAs[W.`5`.T, Int] = WitnessAs(5,5)
- *
- * scala> WitnessAs[_5, Int]
- * res2: WitnessAs[_5, Int] = WitnessAs(Succ(),5)
- * }}}
  */
 final case class WitnessAs[A, B](fst: A, snd: B)
 
-object WitnessAs {
+object WitnessAs extends WitnessAs1 {
   def apply[A, B](implicit ev: WitnessAs[A, B]): WitnessAs[A, B] = ev
 
   implicit def natWitnessAs[B, A <: Nat](implicit
@@ -39,3 +24,56 @@ object WitnessAs {
   ): WitnessAs[A, B] =
     WitnessAs(wa.value, wa.value)
 }
+
+trait WitnessAs1 {
+  implicit def intWitnessAsByte[A <: Int](implicit
+      wa: Witness.Aux[A]
+  ): WitnessAs[A, Byte] =
+    if (wa.value >= Byte.MinValue.toInt && wa.value <= Byte.MaxValue.toInt)
+      WitnessAs(wa.value, wa.value.toByte)
+    else sys.error(s"WitnessAs: ${wa.value} is not in [Byte.MinValue, Byte.MaxValue]")
+
+  implicit def intWitnessAsShort[A <: Int](implicit
+      wa: Witness.Aux[A]
+  ): WitnessAs[A, Short] =
+    if (wa.value >= Short.MinValue.toInt && wa.value <= Short.MaxValue.toInt)
+      WitnessAs(wa.value, wa.value.toShort)
+    else sys.error(s"WitnessAs: ${wa.value} is not in [Short.MinValue, Short.MaxValue]")
+
+  implicit def intWitnessAsLong[A <: Int](implicit
+      wa: Witness.Aux[A]
+  ): WitnessAs[A, Long] =
+    WitnessAs(wa.value, wa.value.toLong)
+
+  implicit def intWitnessAsBigInt[A <: Int](implicit
+      wa: Witness.Aux[A]
+  ): WitnessAs[A, BigInt] =
+    WitnessAs(wa.value, BigInt(wa.value))
+
+  implicit def intWitnessAsFloat[A <: Int](implicit
+      wa: Witness.Aux[A]
+  ): WitnessAs[A, Float] =
+    WitnessAs(wa.value, wa.value.toFloat)
+
+  implicit def intWitnessAsDouble[A <: Int](implicit
+      wa: Witness.Aux[A]
+  ): WitnessAs[A, Double] =
+    WitnessAs(wa.value, wa.value.toDouble)
+
+  implicit def intWitnessAsBigDecimal[A <: Int](implicit
+      wa: Witness.Aux[A]
+  ): WitnessAs[A, BigDecimal] =
+    WitnessAs(wa.value, BigDecimal(wa.value))
+
+  implicit def doubleWitnessAsFloat[A <: Double](implicit
+      wa: Witness.Aux[A]
+  ): WitnessAs[A, Float] =
+    if (wa.value >= Float.MinValue.toDouble && wa.value <= Float.MaxValue.toDouble)
+      WitnessAs(wa.value, wa.value.toFloat)
+    else sys.error(s"WitnessAs: ${wa.value} is not in [Float.MinValue, Float.MaxValue]")
+
+  implicit def doubleWitnessAsBigDecimal[A <: Double](implicit
+      wa: Witness.Aux[A]
+  ): WitnessAs[A, BigDecimal] =
+    WitnessAs(wa.value, BigDecimal(wa.value))
+}
diff --git a/modules/core/shared/src/main/scala-3.0-/eu/timepit/refined/numeric.scala b/modules/core/shared/src/main/scala-3.0-/eu/timepit/refined/numeric.scala
index 42b8d02c9..9aab069ad 100644
--- a/modules/core/shared/src/main/scala-3.0-/eu/timepit/refined/numeric.scala
+++ b/modules/core/shared/src/main/scala-3.0-/eu/timepit/refined/numeric.scala
@@ -6,7 +6,6 @@ import eu.timepit.refined.boolean.{And, Not}
 import eu.timepit.refined.internal.WitnessAs
 import eu.timepit.refined.numeric._
 import shapeless.Nat
-import shapeless.nat.{_0, _2}
 import shapeless.ops.nat.ToInt
 
 /**
@@ -51,25 +50,25 @@ object numeric extends NumericInference {
   type GreaterEqual[N] = Not[Less[N]]
 
   /** Predicate that checks if a numeric value is positive (> 0). */
-  type Positive = Greater[_0]
+  type Positive = Greater[W.`0`.T]
 
   /** Predicate that checks if a numeric value is zero or negative (<= 0). */
   type NonPositive = Not[Positive]
 
   /** Predicate that checks if a numeric value is negative (< 0). */
-  type Negative = Less[_0]
+  type Negative = Less[W.`0`.T]
 
   /** Predicate that checks if a numeric value is zero or positive (>= 0). */
   type NonNegative = Not[Negative]
 
   /** Predicate that checks if an integral value is evenly divisible by `N`. */
-  type Divisible[N] = Modulo[N, _0]
+  type Divisible[N] = Modulo[N, W.`0`.T]
 
   /** Predicate that checks if an integral value is not evenly divisible by `N`. */
   type NonDivisible[N] = Not[Divisible[N]]
 
   /** Predicate that checks if an integral value is evenly divisible by 2. */
-  type Even = Divisible[_2]
+  type Even = Divisible[W.`2`.T]
 
   /** Predicate that checks if an integral value is not evenly divisible by 2. */
   type Odd = Not[Even]
diff --git a/modules/core/shared/src/test/scala-3.0-/eu/timepit/refined/NumericValidateSpec.scala b/modules/core/shared/src/test/scala-3.0-/eu/timepit/refined/NumericValidateSpec.scala
index c84c22c15..32c83aac2 100644
--- a/modules/core/shared/src/test/scala-3.0-/eu/timepit/refined/NumericValidateSpec.scala
+++ b/modules/core/shared/src/test/scala-3.0-/eu/timepit/refined/NumericValidateSpec.scala
@@ -8,9 +8,19 @@ import shapeless.nat._
 
 class NumericValidateSpec extends Properties("NumericValidate") {
 
-  property("Less.isValid") = forAll((d: Double) => isValid[Less[W.`1.0`.T]](d) ?= (d < 1.0))
+  property("isValid[Less[1]](d: Double)") = forAll { (d: Double) =>
+    isValid[Less[W.`1`.T]](d) ?= (d < 1)
+  }
+
+  property("isValid[Less[1.0]](d: Double)") = forAll { (d: Double) =>
+    isValid[Less[W.`1.0`.T]](d) ?= (d < 1.0)
+  }
+
+  property("isValid[Less[1.0]](d: BigDecimal)") = forAll { (d: BigDecimal) =>
+    isValid[Less[W.`1.0`.T]](d) ?= (d < 1.0)
+  }
 
-  property("Less.showExpr") = secure {
+  property("showExpr[Less[1.1]](0.1)") = secure {
     showExpr[Less[W.`1.1`.T]](0.1) ?= "(0.1 < 1.1)"
   }
 
@@ -30,7 +40,11 @@ class NumericValidateSpec extends Properties("NumericValidate") {
     showResult[Less[_5]](i) ?= showResult[Less[W.`5`.T]](i)
   }
 
-  property("Greater.isValid") = forAll { (d: Double) =>
+  property("isValid[Greater[1.0]](b: Byte)") = forAll { (b: Byte) =>
+    isValid[Greater[W.`1`.T]](b) ?= (b > 1)
+  }
+
+  property("isValid[Greater[1.0]](d: Double)") = forAll { (d: Double) =>
     isValid[Greater[W.`1.0`.T]](d) ?= (d > 1.0)
   }
 
@@ -118,13 +132,17 @@ class NumericValidateSpec extends Properties("NumericValidate") {
     showExpr[NonDivisible[_2]](4) ?= "!(4 % 2 == 0)"
   }
 
-  property("Even.isValid") = forAll((i: Int) => isValid[Even](i) ?= (i % 2 == 0))
+  property("Even.isValid") = forAll { (i: Int) =>
+    isValid[Even](i) ?= (i % 2 == 0)
+  }
 
   property("Even.showExpr") = secure {
     showExpr[Even](4) ?= "(4 % 2 == 0)"
   }
 
-  property("Odd.isValid") = forAll((i: Int) => isValid[Odd](i) ?= (i % 2 != 0))
+  property("Odd.isValid") = forAll { (i: Int) =>
+    isValid[Odd](i) ?= (i % 2 != 0)
+  }
 
   property("Odd.showExpr") = secure {
     showExpr[Odd](4) ?= "!(4 % 2 == 0)"
@@ -184,5 +202,4 @@ class NumericValidateSpec extends Properties("NumericValidate") {
   property("NonNaN.Double.showExpr") = secure {
     showExpr[NonNaN](Double.NaN) ?= "(NaN != NaN)"
   }
-
 }
diff --git a/modules/pureconfig/shared/src/test/scala/eu/timepit/refined/pureconfig/RefTypeConfigConvertSpec.scala b/modules/pureconfig/shared/src/test/scala/eu/timepit/refined/pureconfig/RefTypeConfigConvertSpec.scala
index c5ecbf70a..313d4846d 100644
--- a/modules/pureconfig/shared/src/test/scala/eu/timepit/refined/pureconfig/RefTypeConfigConvertSpec.scala
+++ b/modules/pureconfig/shared/src/test/scala/eu/timepit/refined/pureconfig/RefTypeConfigConvertSpec.scala
@@ -24,7 +24,7 @@ class RefTypeConfigConvertSpec extends Properties("RefTypeConfigConvert") {
           reason = CannotConvert(
             value = "0",
             toType =
-              "eu.timepit.refined.api.Refined[Int,eu.timepit.refined.numeric.Greater[shapeless.nat._0]]",
+              "eu.timepit.refined.api.Refined[Int,eu.timepit.refined.numeric.Greater[Int(0)]]",
             because = "Predicate failed: (0 > 0)."
           ),
           origin = Some(ConfigOriginFactory.newSimple("String").withLineNumber(1)),
@@ -41,7 +41,7 @@ class RefTypeConfigConvertSpec extends Properties("RefTypeConfigConvert") {
           reason = CannotConvert(
             value = "0",
             toType =
-              "eu.timepit.refined.api.Refined[scala.Int,eu.timepit.refined.numeric.Greater[shapeless.nat._0]]",
+              "eu.timepit.refined.api.Refined[scala.Int,eu.timepit.refined.numeric.Greater[Int(0)]]",
             because = "Predicate failed: (0 > 0)."
           ),
           origin = Some(ConfigOriginFactory.newSimple("String").withLineNumber(1)),
diff --git a/modules/shapeless/shared/src/test/scala/eu/timepit/refined/shapeless/typeable/TypeableSpec.scala b/modules/shapeless/shared/src/test/scala/eu/timepit/refined/shapeless/typeable/TypeableSpec.scala
index b981ed812..1f5b794e2 100644
--- a/modules/shapeless/shared/src/test/scala/eu/timepit/refined/shapeless/typeable/TypeableSpec.scala
+++ b/modules/shapeless/shared/src/test/scala/eu/timepit/refined/shapeless/typeable/TypeableSpec.scala
@@ -20,7 +20,7 @@ class TypeableSpec extends Properties("shapeless") {
   }
 
   property("Typeable describe") = secure {
-    typeableDescribe[PosInt] ?= "Refined[Int, Greater[_0]]"
+    typeableDescribe[PosInt] ?= "Refined[Int, Greater[Int(0)]]"
   }
 
   property("Typeable cast success string regex") = secure {

From 0557ac8e0b313caf96a628fe09a639cede8ee172 Mon Sep 17 00:00:00 2001
From: "Frank S. Thomas" <frank@timepit.eu>
Date: Sat, 26 Sep 2020 09:51:28 +0200
Subject: [PATCH 2/9] Remove unnecessary WitnessAs1 trait

---
 .../scala-3.0+/eu/timepit/refined/internal/WitnessAs.scala    | 4 +---
 .../scala-3.0-/eu/timepit/refined/internal/WitnessAs.scala    | 4 +---
 2 files changed, 2 insertions(+), 6 deletions(-)

diff --git a/modules/core/shared/src/main/scala-3.0+/eu/timepit/refined/internal/WitnessAs.scala b/modules/core/shared/src/main/scala-3.0+/eu/timepit/refined/internal/WitnessAs.scala
index 4b940e71b..ab0914f04 100644
--- a/modules/core/shared/src/main/scala-3.0+/eu/timepit/refined/internal/WitnessAs.scala
+++ b/modules/core/shared/src/main/scala-3.0+/eu/timepit/refined/internal/WitnessAs.scala
@@ -8,7 +8,7 @@ import shapeless.{Nat, Witness}
  */
 final case class WitnessAs[A, B](fst: A, snd: B)
 
-object WitnessAs extends WitnessAs1 {
+object WitnessAs {
   def apply[A, B](implicit ev: WitnessAs[A, B]): WitnessAs[A, B] = ev
 
   implicit def natWitnessAs[B, A <: Nat](implicit
@@ -22,9 +22,7 @@ object WitnessAs extends WitnessAs1 {
       wa: ValueOf[A]
   ): WitnessAs[A, B] =
     WitnessAs(wa.value, wa.value)
-}
 
-trait WitnessAs1 {
   implicit def intWitnessAsByte[A <: Int](implicit
       wa: ValueOf[A]
   ): WitnessAs[A, Byte] =
diff --git a/modules/core/shared/src/main/scala-3.0-/eu/timepit/refined/internal/WitnessAs.scala b/modules/core/shared/src/main/scala-3.0-/eu/timepit/refined/internal/WitnessAs.scala
index a673f3db4..a1397bdd3 100644
--- a/modules/core/shared/src/main/scala-3.0-/eu/timepit/refined/internal/WitnessAs.scala
+++ b/modules/core/shared/src/main/scala-3.0-/eu/timepit/refined/internal/WitnessAs.scala
@@ -9,7 +9,7 @@ import shapeless.ops.nat.ToInt
  */
 final case class WitnessAs[A, B](fst: A, snd: B)
 
-object WitnessAs extends WitnessAs1 {
+object WitnessAs {
   def apply[A, B](implicit ev: WitnessAs[A, B]): WitnessAs[A, B] = ev
 
   implicit def natWitnessAs[B, A <: Nat](implicit
@@ -23,9 +23,7 @@ object WitnessAs extends WitnessAs1 {
       wa: Witness.Aux[A]
   ): WitnessAs[A, B] =
     WitnessAs(wa.value, wa.value)
-}
 
-trait WitnessAs1 {
   implicit def intWitnessAsByte[A <: Int](implicit
       wa: Witness.Aux[A]
   ): WitnessAs[A, Byte] =

From e8736119f0434f2327ab3d7eb6f4c5226f6a168d Mon Sep 17 00:00:00 2001
From: "Frank S. Thomas" <frank@timepit.eu>
Date: Sat, 26 Sep 2020 15:07:43 +0200
Subject: [PATCH 3/9] Revert "Remove unnecessary WitnessAs1 trait"

This reverts commit 0557ac8e0b313caf96a628fe09a639cede8ee172.
---
 .../scala-3.0+/eu/timepit/refined/internal/WitnessAs.scala    | 4 +++-
 .../scala-3.0-/eu/timepit/refined/internal/WitnessAs.scala    | 4 +++-
 2 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/modules/core/shared/src/main/scala-3.0+/eu/timepit/refined/internal/WitnessAs.scala b/modules/core/shared/src/main/scala-3.0+/eu/timepit/refined/internal/WitnessAs.scala
index ab0914f04..4b940e71b 100644
--- a/modules/core/shared/src/main/scala-3.0+/eu/timepit/refined/internal/WitnessAs.scala
+++ b/modules/core/shared/src/main/scala-3.0+/eu/timepit/refined/internal/WitnessAs.scala
@@ -8,7 +8,7 @@ import shapeless.{Nat, Witness}
  */
 final case class WitnessAs[A, B](fst: A, snd: B)
 
-object WitnessAs {
+object WitnessAs extends WitnessAs1 {
   def apply[A, B](implicit ev: WitnessAs[A, B]): WitnessAs[A, B] = ev
 
   implicit def natWitnessAs[B, A <: Nat](implicit
@@ -22,7 +22,9 @@ object WitnessAs {
       wa: ValueOf[A]
   ): WitnessAs[A, B] =
     WitnessAs(wa.value, wa.value)
+}
 
+trait WitnessAs1 {
   implicit def intWitnessAsByte[A <: Int](implicit
       wa: ValueOf[A]
   ): WitnessAs[A, Byte] =
diff --git a/modules/core/shared/src/main/scala-3.0-/eu/timepit/refined/internal/WitnessAs.scala b/modules/core/shared/src/main/scala-3.0-/eu/timepit/refined/internal/WitnessAs.scala
index a1397bdd3..a673f3db4 100644
--- a/modules/core/shared/src/main/scala-3.0-/eu/timepit/refined/internal/WitnessAs.scala
+++ b/modules/core/shared/src/main/scala-3.0-/eu/timepit/refined/internal/WitnessAs.scala
@@ -9,7 +9,7 @@ import shapeless.ops.nat.ToInt
  */
 final case class WitnessAs[A, B](fst: A, snd: B)
 
-object WitnessAs {
+object WitnessAs extends WitnessAs1 {
   def apply[A, B](implicit ev: WitnessAs[A, B]): WitnessAs[A, B] = ev
 
   implicit def natWitnessAs[B, A <: Nat](implicit
@@ -23,7 +23,9 @@ object WitnessAs {
       wa: Witness.Aux[A]
   ): WitnessAs[A, B] =
     WitnessAs(wa.value, wa.value)
+}
 
+trait WitnessAs1 {
   implicit def intWitnessAsByte[A <: Int](implicit
       wa: Witness.Aux[A]
   ): WitnessAs[A, Byte] =

From 2bee713cd3ca1d2acaad1bdfcb7a4d5a53396f9e Mon Sep 17 00:00:00 2001
From: "Frank S. Thomas" <frank@timepit.eu>
Date: Sat, 26 Sep 2020 15:12:00 +0200
Subject: [PATCH 4/9] Defer changing Positive to 0.10

---
 .../main/scala-3.0+/eu/timepit/refined/numeric.scala  | 11 ++++++-----
 .../main/scala-3.0-/eu/timepit/refined/numeric.scala  |  9 +++++----
 .../refined/pureconfig/RefTypeConfigConvertSpec.scala |  4 ++--
 .../refined/shapeless/typeable/TypeableSpec.scala     |  2 +-
 4 files changed, 14 insertions(+), 12 deletions(-)

diff --git a/modules/core/shared/src/main/scala-3.0+/eu/timepit/refined/numeric.scala b/modules/core/shared/src/main/scala-3.0+/eu/timepit/refined/numeric.scala
index 9ac140823..465ecf545 100644
--- a/modules/core/shared/src/main/scala-3.0+/eu/timepit/refined/numeric.scala
+++ b/modules/core/shared/src/main/scala-3.0+/eu/timepit/refined/numeric.scala
@@ -3,10 +3,11 @@ package eu.timepit.refined
 import eu.timepit.refined.api.{Inference, Validate}
 import eu.timepit.refined.api.Inference.==>
 import eu.timepit.refined.boolean.{And, Not}
+import eu.timepit.refined.internal.ToInt
 import eu.timepit.refined.internal.WitnessAs
 import eu.timepit.refined.numeric._
 import shapeless.Nat
-import shapeless.ops.nat.ToInt
+import shapeless.nat.{_0, _2}
 
 /**
  * Module for numeric predicates. Predicates that take type parameters
@@ -50,25 +51,25 @@ object numeric extends NumericInference {
   type GreaterEqual[N] = Not[Less[N]]
 
   /** Predicate that checks if a numeric value is positive (> 0). */
-  type Positive = Greater[0]
+  type Positive = Greater[_0]
 
   /** Predicate that checks if a numeric value is zero or negative (<= 0). */
   type NonPositive = Not[Positive]
 
   /** Predicate that checks if a numeric value is negative (< 0). */
-  type Negative = Less[0]
+  type Negative = Less[_0]
 
   /** Predicate that checks if a numeric value is zero or positive (>= 0). */
   type NonNegative = Not[Negative]
 
   /** Predicate that checks if an integral value is evenly divisible by `N`. */
-  type Divisible[N] = Modulo[N, 0]
+  type Divisible[N] = Modulo[N, _0]
 
   /** Predicate that checks if an integral value is not evenly divisible by `N`. */
   type NonDivisible[N] = Not[Divisible[N]]
 
   /** Predicate that checks if an integral value is evenly divisible by 2. */
-  type Even = Divisible[2]
+  type Even = Divisible[_2]
 
   /** Predicate that checks if an integral value is not evenly divisible by 2. */
   type Odd = Not[Even]
diff --git a/modules/core/shared/src/main/scala-3.0-/eu/timepit/refined/numeric.scala b/modules/core/shared/src/main/scala-3.0-/eu/timepit/refined/numeric.scala
index 9aab069ad..42b8d02c9 100644
--- a/modules/core/shared/src/main/scala-3.0-/eu/timepit/refined/numeric.scala
+++ b/modules/core/shared/src/main/scala-3.0-/eu/timepit/refined/numeric.scala
@@ -6,6 +6,7 @@ import eu.timepit.refined.boolean.{And, Not}
 import eu.timepit.refined.internal.WitnessAs
 import eu.timepit.refined.numeric._
 import shapeless.Nat
+import shapeless.nat.{_0, _2}
 import shapeless.ops.nat.ToInt
 
 /**
@@ -50,25 +51,25 @@ object numeric extends NumericInference {
   type GreaterEqual[N] = Not[Less[N]]
 
   /** Predicate that checks if a numeric value is positive (> 0). */
-  type Positive = Greater[W.`0`.T]
+  type Positive = Greater[_0]
 
   /** Predicate that checks if a numeric value is zero or negative (<= 0). */
   type NonPositive = Not[Positive]
 
   /** Predicate that checks if a numeric value is negative (< 0). */
-  type Negative = Less[W.`0`.T]
+  type Negative = Less[_0]
 
   /** Predicate that checks if a numeric value is zero or positive (>= 0). */
   type NonNegative = Not[Negative]
 
   /** Predicate that checks if an integral value is evenly divisible by `N`. */
-  type Divisible[N] = Modulo[N, W.`0`.T]
+  type Divisible[N] = Modulo[N, _0]
 
   /** Predicate that checks if an integral value is not evenly divisible by `N`. */
   type NonDivisible[N] = Not[Divisible[N]]
 
   /** Predicate that checks if an integral value is evenly divisible by 2. */
-  type Even = Divisible[W.`2`.T]
+  type Even = Divisible[_2]
 
   /** Predicate that checks if an integral value is not evenly divisible by 2. */
   type Odd = Not[Even]
diff --git a/modules/pureconfig/shared/src/test/scala/eu/timepit/refined/pureconfig/RefTypeConfigConvertSpec.scala b/modules/pureconfig/shared/src/test/scala/eu/timepit/refined/pureconfig/RefTypeConfigConvertSpec.scala
index 313d4846d..c5ecbf70a 100644
--- a/modules/pureconfig/shared/src/test/scala/eu/timepit/refined/pureconfig/RefTypeConfigConvertSpec.scala
+++ b/modules/pureconfig/shared/src/test/scala/eu/timepit/refined/pureconfig/RefTypeConfigConvertSpec.scala
@@ -24,7 +24,7 @@ class RefTypeConfigConvertSpec extends Properties("RefTypeConfigConvert") {
           reason = CannotConvert(
             value = "0",
             toType =
-              "eu.timepit.refined.api.Refined[Int,eu.timepit.refined.numeric.Greater[Int(0)]]",
+              "eu.timepit.refined.api.Refined[Int,eu.timepit.refined.numeric.Greater[shapeless.nat._0]]",
             because = "Predicate failed: (0 > 0)."
           ),
           origin = Some(ConfigOriginFactory.newSimple("String").withLineNumber(1)),
@@ -41,7 +41,7 @@ class RefTypeConfigConvertSpec extends Properties("RefTypeConfigConvert") {
           reason = CannotConvert(
             value = "0",
             toType =
-              "eu.timepit.refined.api.Refined[scala.Int,eu.timepit.refined.numeric.Greater[Int(0)]]",
+              "eu.timepit.refined.api.Refined[scala.Int,eu.timepit.refined.numeric.Greater[shapeless.nat._0]]",
             because = "Predicate failed: (0 > 0)."
           ),
           origin = Some(ConfigOriginFactory.newSimple("String").withLineNumber(1)),
diff --git a/modules/shapeless/shared/src/test/scala/eu/timepit/refined/shapeless/typeable/TypeableSpec.scala b/modules/shapeless/shared/src/test/scala/eu/timepit/refined/shapeless/typeable/TypeableSpec.scala
index 1f5b794e2..6ba5640f3 100644
--- a/modules/shapeless/shared/src/test/scala/eu/timepit/refined/shapeless/typeable/TypeableSpec.scala
+++ b/modules/shapeless/shared/src/test/scala/eu/timepit/refined/shapeless/typeable/TypeableSpec.scala
@@ -20,7 +20,7 @@ class TypeableSpec extends Properties("shapeless") {
   }
 
   property("Typeable describe") = secure {
-    typeableDescribe[PosInt] ?= "Refined[Int, Greater[Int(0)]]"
+    typeableDescribe[PosInt] ?= "Refined[Int, Greater[shapeless.nat._0]]"
   }
 
   property("Typeable cast success string regex") = secure {

From 035778a36ad09a944105972bb312de68052e3e43 Mon Sep 17 00:00:00 2001
From: "Frank S. Thomas" <frank@timepit.eu>
Date: Sat, 26 Sep 2020 15:16:23 +0200
Subject: [PATCH 5/9] Fix test

---
 .../eu/timepit/refined/shapeless/typeable/TypeableSpec.scala    | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/modules/shapeless/shared/src/test/scala/eu/timepit/refined/shapeless/typeable/TypeableSpec.scala b/modules/shapeless/shared/src/test/scala/eu/timepit/refined/shapeless/typeable/TypeableSpec.scala
index 6ba5640f3..b981ed812 100644
--- a/modules/shapeless/shared/src/test/scala/eu/timepit/refined/shapeless/typeable/TypeableSpec.scala
+++ b/modules/shapeless/shared/src/test/scala/eu/timepit/refined/shapeless/typeable/TypeableSpec.scala
@@ -20,7 +20,7 @@ class TypeableSpec extends Properties("shapeless") {
   }
 
   property("Typeable describe") = secure {
-    typeableDescribe[PosInt] ?= "Refined[Int, Greater[shapeless.nat._0]]"
+    typeableDescribe[PosInt] ?= "Refined[Int, Greater[_0]]"
   }
 
   property("Typeable cast success string regex") = secure {

From 88d86893f90252a3ce86931b558985223820f7be Mon Sep 17 00:00:00 2001
From: "Frank S. Thomas" <frank@timepit.eu>
Date: Sat, 26 Sep 2020 16:23:35 +0200
Subject: [PATCH 6/9] Document the purpose of WitnessAs

---
 .../eu/timepit/refined/internal/WitnessAs.scala  | 16 ++++++++++++++++
 .../eu/timepit/refined/internal/WitnessAs.scala  | 16 ++++++++++++++++
 2 files changed, 32 insertions(+)

diff --git a/modules/core/shared/src/main/scala-3.0+/eu/timepit/refined/internal/WitnessAs.scala b/modules/core/shared/src/main/scala-3.0+/eu/timepit/refined/internal/WitnessAs.scala
index 4b940e71b..7e4618db2 100644
--- a/modules/core/shared/src/main/scala-3.0+/eu/timepit/refined/internal/WitnessAs.scala
+++ b/modules/core/shared/src/main/scala-3.0+/eu/timepit/refined/internal/WitnessAs.scala
@@ -5,6 +5,22 @@ import shapeless.{Nat, Witness}
 /**
  * `WitnessAs[A, B]` provides the singleton value of type `A` in `fst`
  * and `fst` converted to type `B` in `snd`.
+ *
+ * The purpose of this type class is to allow literals of other
+ * types than the base type to be used as arguments in numeric
+ * predicates.
+ *
+ * Example: {{{
+ * scala> import eu.timepit.refined.refineV
+ *      | import eu.timepit.refined.api.Refined
+ *      | import eu.timepit.refined.numeric.{Greater, Less}
+ *
+ * scala> refineV[Greater[2.718]](BigDecimal(3.141))
+ * res0: Either[String, BigDecimal Refined Greater[2.718]] = Right(3.141)
+ *
+ * scala> refineV[Less[1]](0.618)
+ * res1: Either[String, Double Refined Less[1]] = Right(0.618)
+ * }}}
  */
 final case class WitnessAs[A, B](fst: A, snd: B)
 
diff --git a/modules/core/shared/src/main/scala-3.0-/eu/timepit/refined/internal/WitnessAs.scala b/modules/core/shared/src/main/scala-3.0-/eu/timepit/refined/internal/WitnessAs.scala
index a673f3db4..9ebc52ec9 100644
--- a/modules/core/shared/src/main/scala-3.0-/eu/timepit/refined/internal/WitnessAs.scala
+++ b/modules/core/shared/src/main/scala-3.0-/eu/timepit/refined/internal/WitnessAs.scala
@@ -6,6 +6,22 @@ import shapeless.ops.nat.ToInt
 /**
  * `WitnessAs[A, B]` provides the singleton value of type `A` in `fst`
  * and `fst` converted to type `B` in `snd`.
+ *
+ * The purpose of this type class is to allow literals of other
+ * types than the base type to be used as arguments in numeric
+ * predicates.
+ *
+ * Example: {{{
+ * scala> import eu.timepit.refined.{refineV, W}
+ *      | import eu.timepit.refined.api.Refined
+ *      | import eu.timepit.refined.numeric.{Greater, Less}
+ *
+ * scala> refineV[Greater[W.`2.718`.T]](BigDecimal(3.141))
+ * res0: Either[String, BigDecimal Refined Greater[W.`2.718`.T]] = Right(3.141)
+ *
+ * scala> refineV[Less[W.`1`.T]](0.618)
+ * res1: Either[String, Double Refined Less[W.`1`.T]] = Right(0.618)
+ * }}}
  */
 final case class WitnessAs[A, B](fst: A, snd: B)
 

From 23e9cef225faa0834bfa499927e9410c9788b16b Mon Sep 17 00:00:00 2001
From: "Frank S. Thomas" <frank@timepit.eu>
Date: Sat, 26 Sep 2020 19:56:57 +0200
Subject: [PATCH 7/9] Check bounds of some WitnessAs instances at compile-time

---
 .../timepit/refined/internal/WitnessAs.scala  | 82 +++++++++----------
 1 file changed, 40 insertions(+), 42 deletions(-)

diff --git a/modules/core/shared/src/main/scala-3.0+/eu/timepit/refined/internal/WitnessAs.scala b/modules/core/shared/src/main/scala-3.0+/eu/timepit/refined/internal/WitnessAs.scala
index 7e4618db2..692249dd5 100644
--- a/modules/core/shared/src/main/scala-3.0+/eu/timepit/refined/internal/WitnessAs.scala
+++ b/modules/core/shared/src/main/scala-3.0+/eu/timepit/refined/internal/WitnessAs.scala
@@ -1,5 +1,6 @@
 package eu.timepit.refined.internal
 
+import scala.compiletime.{constValue, error}
 import shapeless.{Nat, Witness}
 
 /**
@@ -41,54 +42,51 @@ object WitnessAs extends WitnessAs1 {
 }
 
 trait WitnessAs1 {
-  implicit def intWitnessAsByte[A <: Int](implicit
-      wa: ValueOf[A]
-  ): WitnessAs[A, Byte] =
-    if (wa.value >= Byte.MinValue.toInt && wa.value <= Byte.MaxValue.toInt)
-      WitnessAs(wa.value, wa.value.toByte)
-    else sys.error(s"WitnessAs: ${wa.value} is not in [Byte.MinValue, Byte.MaxValue]")
+  inline implicit def intWitnessAsByte[A <: Int]: WitnessAs[A, Byte] =
+    inline constValue[A] match {
+      case a if a >= -128 && a <= 127 => WitnessAs(a, a.toByte)
+      case a => error(s"WitnessAs: $a is not in [Byte.MinValue, Byte.MaxValue]")
+    }
 
-  implicit def intWitnessAsShort[A <: Int](implicit
-      wa: ValueOf[A]
-  ): WitnessAs[A, Short] =
-    if (wa.value >= Short.MinValue.toInt && wa.value <= Short.MaxValue.toInt)
-      WitnessAs(wa.value, wa.value.toShort)
-    else sys.error(s"WitnessAs: ${wa.value} is not in [Short.MinValue, Short.MaxValue]")
+  inline implicit def intWitnessAsShort[A <: Int]: WitnessAs[A, Short] =
+    inline constValue[A] match {
+      case a if a >= -32768 && a <= 32767 => WitnessAs(a, a.toShort)
+      case a => error(s"WitnessAs: $a is not in [Short.MinValue, Short.MaxValue]")
+    }
 
-  implicit def intWitnessAsLong[A <: Int](implicit
-      wa: ValueOf[A]
-  ): WitnessAs[A, Long] =
-    WitnessAs(wa.value, wa.value.toLong)
+  inline implicit def intWitnessAsLong[A <: Int]: WitnessAs[A, Long] = {
+    inline val a = constValue[A]
+    WitnessAs(a, a.toLong)
+  }
 
-  implicit def intWitnessAsBigInt[A <: Int](implicit
-      wa: ValueOf[A]
-  ): WitnessAs[A, BigInt] =
-    WitnessAs(wa.value, BigInt(wa.value))
+  inline implicit def intWitnessAsBigInt[A <: Int]: WitnessAs[A, BigInt] = {
+    inline val a = constValue[A]
+    WitnessAs(a, BigInt(a))
+  }
 
-  implicit def intWitnessAsFloat[A <: Int](implicit
-      wa: ValueOf[A]
-  ): WitnessAs[A, Float] =
-    WitnessAs(wa.value, wa.value.toFloat)
+  inline implicit def intWitnessAsFloat[A <: Int]: WitnessAs[A, Float] = {
+    inline val a = constValue[A]
+    WitnessAs(a, a.toFloat)
+  }
 
-  implicit def intWitnessAsDouble[A <: Int](implicit
-      wa: ValueOf[A]
-  ): WitnessAs[A, Double] =
-    WitnessAs(wa.value, wa.value.toDouble)
+  inline implicit def intWitnessAsDouble[A <: Int]: WitnessAs[A, Double] = {
+    inline val a = constValue[A]
+    WitnessAs(a, a.toDouble)
+  }
 
-  implicit def intWitnessAsBigDecimal[A <: Int](implicit
-      wa: ValueOf[A]
-  ): WitnessAs[A, BigDecimal] =
-    WitnessAs(wa.value, BigDecimal(wa.value))
+  inline implicit def intWitnessAsBigDecimal[A <: Int]: WitnessAs[A, BigDecimal] = {
+    inline val a = constValue[A]
+    WitnessAs(a, BigDecimal(a))
+  }
 
-  implicit def doubleWitnessAsFloat[A <: Double](implicit
-      wa: ValueOf[A]
-  ): WitnessAs[A, Float] =
-    if (wa.value >= Float.MinValue.toDouble && wa.value <= Float.MaxValue.toDouble)
-      WitnessAs(wa.value, wa.value.toFloat)
-    else sys.error(s"WitnessAs: ${wa.value} is not in [Float.MinValue, Float.MaxValue]")
+  inline implicit def doubleWitnessAsFloat[A <: Double]: WitnessAs[A, Float] =
+    inline constValue[A] match {
+      case a if a >= -3.4028235E38 && a <= 3.4028235E38 => WitnessAs(a, a.toFloat)
+      case a => error(s"WitnessAs: $a is not in [Float.MinValue, Float.MaxValue]")
+    }
 
-  implicit def doubleWitnessAsBigDecimal[A <: Double](implicit
-      wa: ValueOf[A]
-  ): WitnessAs[A, BigDecimal] =
-    WitnessAs(wa.value, BigDecimal(wa.value))
+  inline implicit def doubleWitnessAsBigDecimal[A <: Double]: WitnessAs[A, BigDecimal] = {
+    inline val a = constValue[A]
+    WitnessAs(a, BigDecimal(a))
+  }
 }

From f73a80c9cf9cba492397cd655fb651c4a17971b4 Mon Sep 17 00:00:00 2001
From: "Frank S. Thomas" <frank@timepit.eu>
Date: Sat, 26 Sep 2020 20:01:42 +0200
Subject: [PATCH 8/9] Use constValue instead of ValueOf

---
 .../eu/timepit/refined/internal/WitnessAs.scala           | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/modules/core/shared/src/main/scala-3.0+/eu/timepit/refined/internal/WitnessAs.scala b/modules/core/shared/src/main/scala-3.0+/eu/timepit/refined/internal/WitnessAs.scala
index 692249dd5..4805fe36d 100644
--- a/modules/core/shared/src/main/scala-3.0+/eu/timepit/refined/internal/WitnessAs.scala
+++ b/modules/core/shared/src/main/scala-3.0+/eu/timepit/refined/internal/WitnessAs.scala
@@ -35,10 +35,10 @@ object WitnessAs extends WitnessAs1 {
   ): WitnessAs[A, B] =
     WitnessAs(wa.value, nb.fromInt(ta.apply()))
 
-  implicit def singletonWitnessAs[B, A <: B](implicit
-      wa: ValueOf[A]
-  ): WitnessAs[A, B] =
-    WitnessAs(wa.value, wa.value)
+  inline implicit def singletonWitnessAs[B, A <: B]: WitnessAs[A, B] = {
+    inline val a = constValue[A]
+    WitnessAs(a, a)
+  }
 }
 
 trait WitnessAs1 {

From 61ba27f600b37841765871d5948a9d6a82613c67 Mon Sep 17 00:00:00 2001
From: "Frank S. Thomas" <frank@timepit.eu>
Date: Sat, 26 Sep 2020 20:12:06 +0200
Subject: [PATCH 9/9] Use given instead of implicit def

---
 .../timepit/refined/internal/WitnessAs.scala  | 20 +++++++++----------
 1 file changed, 10 insertions(+), 10 deletions(-)

diff --git a/modules/core/shared/src/main/scala-3.0+/eu/timepit/refined/internal/WitnessAs.scala b/modules/core/shared/src/main/scala-3.0+/eu/timepit/refined/internal/WitnessAs.scala
index 4805fe36d..0011833a0 100644
--- a/modules/core/shared/src/main/scala-3.0+/eu/timepit/refined/internal/WitnessAs.scala
+++ b/modules/core/shared/src/main/scala-3.0+/eu/timepit/refined/internal/WitnessAs.scala
@@ -35,57 +35,57 @@ object WitnessAs extends WitnessAs1 {
   ): WitnessAs[A, B] =
     WitnessAs(wa.value, nb.fromInt(ta.apply()))
 
-  inline implicit def singletonWitnessAs[B, A <: B]: WitnessAs[A, B] = {
+  inline given singletonWitnessAs[B, A <: B] as WitnessAs[A, B] = {
     inline val a = constValue[A]
     WitnessAs(a, a)
   }
 }
 
 trait WitnessAs1 {
-  inline implicit def intWitnessAsByte[A <: Int]: WitnessAs[A, Byte] =
+  inline given intWitnessAsByte[A <: Int] as WitnessAs[A, Byte] =
     inline constValue[A] match {
       case a if a >= -128 && a <= 127 => WitnessAs(a, a.toByte)
       case a => error(s"WitnessAs: $a is not in [Byte.MinValue, Byte.MaxValue]")
     }
 
-  inline implicit def intWitnessAsShort[A <: Int]: WitnessAs[A, Short] =
+  inline given intWitnessAsShort[A <: Int] as WitnessAs[A, Short] =
     inline constValue[A] match {
       case a if a >= -32768 && a <= 32767 => WitnessAs(a, a.toShort)
       case a => error(s"WitnessAs: $a is not in [Short.MinValue, Short.MaxValue]")
     }
 
-  inline implicit def intWitnessAsLong[A <: Int]: WitnessAs[A, Long] = {
+  inline given intWitnessAsLong[A <: Int] as WitnessAs[A, Long] = {
     inline val a = constValue[A]
     WitnessAs(a, a.toLong)
   }
 
-  inline implicit def intWitnessAsBigInt[A <: Int]: WitnessAs[A, BigInt] = {
+  inline given intWitnessAsBigInt[A <: Int] as WitnessAs[A, BigInt] = {
     inline val a = constValue[A]
     WitnessAs(a, BigInt(a))
   }
 
-  inline implicit def intWitnessAsFloat[A <: Int]: WitnessAs[A, Float] = {
+  inline given intWitnessAsFloat[A <: Int] as WitnessAs[A, Float] = {
     inline val a = constValue[A]
     WitnessAs(a, a.toFloat)
   }
 
-  inline implicit def intWitnessAsDouble[A <: Int]: WitnessAs[A, Double] = {
+  inline given intWitnessAsDouble[A <: Int] as WitnessAs[A, Double] = {
     inline val a = constValue[A]
     WitnessAs(a, a.toDouble)
   }
 
-  inline implicit def intWitnessAsBigDecimal[A <: Int]: WitnessAs[A, BigDecimal] = {
+  inline given intWitnessAsBigDecimal[A <: Int] as WitnessAs[A, BigDecimal] = {
     inline val a = constValue[A]
     WitnessAs(a, BigDecimal(a))
   }
 
-  inline implicit def doubleWitnessAsFloat[A <: Double]: WitnessAs[A, Float] =
+  inline given doubleWitnessAsFloat[A <: Double] as WitnessAs[A, Float] =
     inline constValue[A] match {
       case a if a >= -3.4028235E38 && a <= 3.4028235E38 => WitnessAs(a, a.toFloat)
       case a => error(s"WitnessAs: $a is not in [Float.MinValue, Float.MaxValue]")
     }
 
-  inline implicit def doubleWitnessAsBigDecimal[A <: Double]: WitnessAs[A, BigDecimal] = {
+  inline given doubleWitnessAsBigDecimal[A <: Double] as WitnessAs[A, BigDecimal] = {
     inline val a = constValue[A]
     WitnessAs(a, BigDecimal(a))
   }