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nicolasstuckinicolasstucki
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Fix Reflection wildcard abstraction
Currently, we are missing in the API the Wildcard concept for `case _ =>` patterns. These are encoded as term `Ident` with name `_`. This tree can be inconsistently matched by `Ident`, `TypeIdent` or `WildcardTypeTree`. There is also no way to create an `Ident(_)`. Changes * `Ident` does not match `Ident(_)` * `TypeIdent` does not match `Ident(_)` * `WildcardTypeTree` does not match `Ident(_)` if it is a term * Add `Wildcard` type that matches a term `Ident(_)` Fixes #12188
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13 files changed

+113
-22
lines changed

13 files changed

+113
-22
lines changed

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

+22-4
Original file line numberDiff line numberDiff line change
@@ -97,7 +97,7 @@ class QuotesImpl private (using val ctx: Context) extends Quotes, QuoteUnpickler
9797
new ExprImpl(self, SpliceScope.getCurrent)
9898
else self match
9999
case TermTypeTest(self) => throw new Exception("Expected an expression. This is a partially applied Term. Try eta-expanding the term first.")
100-
case _ => throw new Exception("Expected a Term but was: " + self)
100+
case _ => throw new Exception("Expected a Term but was: " + Printer.TreeStructure.show(self))
101101
end extension
102102

103103
extension (self: Tree)
@@ -332,8 +332,11 @@ class QuotesImpl private (using val ctx: Context) extends Quotes, QuoteUnpickler
332332

333333
object TermTypeTest extends TypeTest[Tree, Term]:
334334
def unapply(x: Tree): Option[Term & x.type] = x match
335+
// Patterns
335336
case _ if UnapplyTypeTest.unapply(x).isDefined => None
336337
case _: tpd.PatternTree => None
338+
case x: (tpd.Ident & x.type) if x.isTerm && x.name == nme.WILDCARD => None
339+
// Terms
337340
case x: (tpd.Tree & x.type) if x.isTerm => Some(x)
338341
case x: (tpd.SeqLiteral & x.type) => Some(x)
339342
case x: (tpd.Inlined & x.type) => Some(x)
@@ -422,7 +425,7 @@ class QuotesImpl private (using val ctx: Context) extends Quotes, QuoteUnpickler
422425

423426
object IdentTypeTest extends TypeTest[Tree, Ident]:
424427
def unapply(x: Tree): Option[Ident & x.type] = x match
425-
case x: (tpd.Ident & x.type) if x.isTerm => Some(x)
428+
case x: (tpd.Ident & x.type) if x.isTerm && x.name != nme.WILDCARD => Some(x)
426429
case _ => None
427430
end IdentTypeTest
428431

@@ -1021,7 +1024,7 @@ class QuotesImpl private (using val ctx: Context) extends Quotes, QuoteUnpickler
10211024

10221025
object TypeIdentTypeTest extends TypeTest[Tree, TypeIdent]:
10231026
def unapply(x: Tree): Option[TypeIdent & x.type] = x match
1024-
case tpt: (tpd.Ident & x.type) if tpt.isType => Some(tpt)
1027+
case tpt: (tpd.Ident & x.type) if tpt.isType && tpt.name != nme.WILDCARD => Some(tpt)
10251028
case _ => None
10261029
end TypeIdentTypeTest
10271030

@@ -1335,7 +1338,7 @@ class QuotesImpl private (using val ctx: Context) extends Quotes, QuoteUnpickler
13351338

13361339
object WildcardTypeTreeTypeTest extends TypeTest[Tree, WildcardTypeTree]:
13371340
def unapply(x: Tree): Option[WildcardTypeTree & x.type] = x match
1338-
case x: (tpd.Ident & x.type) if x.name == nme.WILDCARD => Some(x)
1341+
case x: (tpd.Ident & x.type) if x.isType && x.name == nme.WILDCARD => Some(x)
13391342
case _ => None
13401343
end WildcardTypeTreeTypeTest
13411344

@@ -1399,6 +1402,21 @@ class QuotesImpl private (using val ctx: Context) extends Quotes, QuoteUnpickler
13991402
end extension
14001403
end TypeCaseDefMethods
14011404

1405+
1406+
type Wildcard = tpd.Ident
1407+
1408+
object WildcardTypeTest extends TypeTest[Tree, Wildcard]:
1409+
def unapply(x: Tree): Option[Wildcard & x.type] = x match
1410+
case x: (tpd.Ident & x.type) if x.name == nme.WILDCARD => Some(x)
1411+
case _ => None
1412+
end WildcardTypeTest
1413+
1414+
object Wildcard extends WildcardModule:
1415+
def apply(): Wildcard =
1416+
withDefaultPos(untpd.Ident(nme.WILDCARD).withType(dotc.core.Symbols.defn.AnyType))
1417+
def unapply(pattern: Wildcard): true = true
1418+
end Wildcard
1419+
14021420
type Bind = tpd.Bind
14031421

14041422
object BindTypeTest extends TypeTest[Tree, Bind]:

‎compiler/src/scala/quoted/runtime/impl/printers/Extractors.scala

+2
Original file line numberDiff line numberDiff line change
@@ -165,6 +165,8 @@ object Extractors {
165165
this += "CaseDef(" += pat += ", " += guard += ", " += body += ")"
166166
case TypeCaseDef(pat, body) =>
167167
this += "TypeCaseDef(" += pat += ", " += body += ")"
168+
case Wildcard() =>
169+
this += "Wildcard()"
168170
case Bind(name, body) =>
169171
this += "Bind(\"" += name += "\", " += body += ")"
170172
case Unapply(fun, implicits, patterns) =>

‎compiler/src/scala/quoted/runtime/impl/printers/SourceCode.scala

+5-5
Original file line numberDiff line numberDiff line change
@@ -328,7 +328,7 @@ object SourceCode {
328328
}
329329
this
330330

331-
case Ident("_") =>
331+
case Wildcard() =>
332332
this += "_"
333333

334334
case tree: Ident =>
@@ -893,13 +893,13 @@ object SourceCode {
893893
}
894894

895895
private def printPattern(pattern: Tree): this.type = pattern match {
896-
case Ident("_") =>
896+
case Wildcard() =>
897897
this += "_"
898898

899-
case Bind(name, Ident("_")) =>
899+
case Bind(name, Wildcard()) =>
900900
this += name
901901

902-
case Bind(name, Typed(Ident("_"), tpt)) =>
902+
case Bind(name, Typed(Wildcard(), tpt)) =>
903903
this += highlightValDef(name) += ": "
904904
printTypeTree(tpt)
905905

@@ -925,7 +925,7 @@ object SourceCode {
925925
case Alternatives(trees) =>
926926
inParens(printPatterns(trees, " | "))
927927

928-
case Typed(Ident("_"), tpt) =>
928+
case Typed(Wildcard(), tpt) =>
929929
this += "_: "
930930
printTypeTree(tpt)
931931

‎library/src/scala/quoted/Quotes.scala

+18
Original file line numberDiff line numberDiff line change
@@ -157,6 +157,7 @@ trait Quotes { self: runtime.QuoteUnpickler & runtime.QuoteMatching =>
157157
* +- CaseDef
158158
* |
159159
* +- TypeCaseDef
160+
* +- Wildcard
160161
* +- Bind
161162
* +- Unapply
162163
* +- Alternatives
@@ -2020,6 +2021,21 @@ trait Quotes { self: runtime.QuoteUnpickler & runtime.QuoteMatching =>
20202021

20212022
// ----- Patterns ------------------------------------------------
20222023

2024+
/** Pattern representing a `_` wildcard. */
2025+
type Wildcard <: Tree
2026+
2027+
/** `TypeTest` that allows testing at runtime in a pattern match if a `Tree` is a `Wildcard` */
2028+
given WildcardTypeTest: TypeTest[Tree, Wildcard]
2029+
2030+
/** Module object of `type Wildcard` */
2031+
val Wildcard: WildcardModule
2032+
2033+
/** Methods of the module object `val Wildcard` */
2034+
trait WildcardModule { this: Wildcard.type =>
2035+
def apply(): Wildcard
2036+
def unapply(pattern: Wildcard): true
2037+
}
2038+
20232039
/** Pattern representing a `_ @ _` binding. */
20242040
type Bind <: Tree
20252041

@@ -4243,6 +4259,7 @@ trait Quotes { self: runtime.QuoteUnpickler & runtime.QuoteMatching =>
42434259
case TypeBoundsTree(lo, hi) => foldTree(foldTree(x, lo)(owner), hi)(owner)
42444260
case CaseDef(pat, guard, body) => foldTree(foldTrees(foldTree(x, pat)(owner), guard)(owner), body)(owner)
42454261
case TypeCaseDef(pat, body) => foldTree(foldTree(x, pat)(owner), body)(owner)
4262+
case Wildcard() => x
42464263
case Bind(_, body) => foldTree(x, body)(owner)
42474264
case Unapply(fun, implicits, patterns) => foldTrees(foldTrees(foldTree(x, fun)(owner), implicits)(owner), patterns)(owner)
42484265
case Alternatives(patterns) => foldTrees(x, patterns)(owner)
@@ -4303,6 +4320,7 @@ trait Quotes { self: runtime.QuoteUnpickler & runtime.QuoteMatching =>
43034320
transformCaseDef(tree)(owner)
43044321
case tree: TypeCaseDef =>
43054322
transformTypeCaseDef(tree)(owner)
4323+
case Wildcard() => tree
43064324
case pattern: Bind =>
43074325
Bind.copy(pattern)(pattern.name, pattern.pattern)
43084326
case pattern: Unapply =>

‎tests/pos-macros/i12188b/Macro_1.scala

+13
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,13 @@
1+
import scala.quoted.*
2+
3+
object MatchTest {
4+
inline def test[T](inline obj: Any): Unit = ${testImpl('obj)}
5+
6+
def testImpl[T](objExpr: Expr[T])(using Quotes): Expr[Unit] = {
7+
import quotes.reflect.*
8+
// test that the extractors work
9+
val Inlined(None, Nil, Block(Nil, Match(param @ Ident("a"), List(CaseDef(Literal(IntConstant(1)), None, Block(Nil, Literal(UnitConstant()))), CaseDef(Wildcard(), None, Block(Nil, Literal(UnitConstant()))))))) = objExpr.asTerm
10+
// test that the constructors work
11+
Block(Nil, Match(param, List(CaseDef(Literal(IntConstant(1)), None, Block(Nil, Literal(UnitConstant()))), CaseDef(Wildcard(), None, Block(Nil, Literal(UnitConstant())))))).asExprOf[Unit]
12+
}
13+
}

‎tests/pos-macros/i12188b/Test_2.scala

+6
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,6 @@
1+
2+
def test(a: Int) = MatchTest.test {
3+
a match
4+
case 1 =>
5+
case _ =>
6+
}

‎tests/run-custom-args/Yretain-trees/tasty-definitions-2.check

+1-1
Original file line numberDiff line numberDiff line change
@@ -1,3 +1,3 @@
11
DefDef("foo", Nil, TypeIdent("Int"), Some(Apply(Select(Literal(IntConstant(1)), "+"), List(Literal(IntConstant(2))))))
22
ValDef("bar", TypeIdent("Int"), Some(Apply(Select(Literal(IntConstant(2)), "+"), List(Literal(IntConstant(3))))))
3-
Bind("x", Ident("_"))
3+
Bind("x", Wildcard())

‎tests/run-custom-args/Yretain-trees/tasty-definitions-3.check

+1-1
Original file line numberDiff line numberDiff line change
@@ -1,3 +1,3 @@
11
DefDef("foo", Nil, TypeIdent("Int"), Some(Apply(Select(Literal(IntConstant(1)), "+"), List(Literal(IntConstant(2))))))
22
ValDef("bar", TypeIdent("Int"), Some(Apply(Select(Literal(IntConstant(2)), "+"), List(Literal(IntConstant(3))))))
3-
Bind("x", Ident("_"))
3+
Bind("x", Wildcard())

‎tests/run-macros/i12188.check

+3
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,3 @@
1+
PC1
2+
PC2
3+
default

‎tests/run-macros/i12188/Macro_1.scala

+23
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,23 @@
1+
import scala.quoted.*
2+
3+
object MatchTest {
4+
inline def test[T](inline obj: T): String = ${testImpl('obj)}
5+
6+
def testImpl[T](objExpr: Expr[T])(using qctx: Quotes, t: Type[T]): Expr[String] = {
7+
import qctx.reflect.*
8+
9+
val obj = objExpr.asTerm
10+
val cases = obj.tpe.typeSymbol.children.map { child =>
11+
val subtype = TypeIdent(child)
12+
val bind = Symbol.newBind(Symbol.spliceOwner, "c", Flags.EmptyFlags, subtype.tpe)
13+
CaseDef(Bind(bind, Typed(Ref(bind), subtype)), None, Literal(StringConstant(subtype.show)))
14+
} ::: {
15+
CaseDef(Wildcard(), None, Literal(StringConstant("default")))
16+
} :: Nil
17+
val bind = Symbol.newBind(Symbol.spliceOwner, "o", Flags.EmptyFlags, obj.tpe)
18+
val result = Match(obj, cases)
19+
val code = result.show(using Printer.TreeAnsiCode)
20+
// println(code)
21+
result.asExprOf[String]
22+
}
23+
}

‎tests/run-macros/i12188/Test_2.scala

+8
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,8 @@
1+
sealed trait P
2+
case class PC1(a: String) extends P
3+
case class PC2(b: Int) extends P
4+
5+
@main def Test =
6+
println(MatchTest.test(PC1("ab"): P))
7+
println(MatchTest.test(PC2(10): P))
8+
println(MatchTest.test(null: P))

‎tests/run-macros/tasty-extractors-1.check

+10-10
Original file line numberDiff line numberDiff line change
@@ -40,37 +40,37 @@ OrType(ConstantType(IntConstant(1)), ConstantType(IntConstant(2)))
4040
Inlined(None, Nil, Match(Literal(StringConstant("a")), List(CaseDef(Literal(StringConstant("a")), None, Block(Nil, Literal(UnitConstant()))))))
4141
TypeRef(ThisType(TypeRef(NoPrefix(), "scala")), "Unit")
4242

43-
Inlined(None, Nil, Match(Literal(StringConstant("b")), List(CaseDef(Bind("n", Ident("_")), None, Block(Nil, Literal(UnitConstant()))))))
43+
Inlined(None, Nil, Match(Literal(StringConstant("b")), List(CaseDef(Bind("n", Wildcard()), None, Block(Nil, Literal(UnitConstant()))))))
4444
TypeRef(ThisType(TypeRef(NoPrefix(), "scala")), "Unit")
4545

46-
Inlined(None, Nil, Match(Literal(StringConstant("c")), List(CaseDef(Bind("n", Typed(Ident("_"), TypeIdent("String"))), None, Block(Nil, Literal(UnitConstant()))))))
46+
Inlined(None, Nil, Match(Literal(StringConstant("c")), List(CaseDef(Bind("n", Typed(Wildcard(), TypeIdent("String"))), None, Block(Nil, Literal(UnitConstant()))))))
4747
TypeRef(ThisType(TypeRef(NoPrefix(), "scala")), "Unit")
4848

49-
Inlined(None, Nil, Match(Literal(StringConstant("e")), List(CaseDef(Ident("_"), None, Block(Nil, Literal(UnitConstant()))))))
49+
Inlined(None, Nil, Match(Literal(StringConstant("e")), List(CaseDef(Wildcard(), None, Block(Nil, Literal(UnitConstant()))))))
5050
TypeRef(ThisType(TypeRef(NoPrefix(), "scala")), "Unit")
5151

52-
Inlined(None, Nil, Match(Literal(StringConstant("f")), List(CaseDef(Typed(Ident("_"), TypeIdent("String")), None, Block(Nil, Literal(UnitConstant()))))))
52+
Inlined(None, Nil, Match(Literal(StringConstant("f")), List(CaseDef(Typed(Wildcard(), TypeIdent("String")), None, Block(Nil, Literal(UnitConstant()))))))
5353
TypeRef(ThisType(TypeRef(NoPrefix(), "scala")), "Unit")
5454

55-
Inlined(None, Nil, Match(Typed(Literal(StringConstant("g")), TypeIdent("Any")), List(CaseDef(Alternative(List(Typed(Ident("_"), TypeIdent("String")), Typed(Ident("_"), TypeIdent("Int")))), None, Block(Nil, Literal(UnitConstant()))))))
55+
Inlined(None, Nil, Match(Typed(Literal(StringConstant("g")), TypeIdent("Any")), List(CaseDef(Alternative(List(Typed(Wildcard(), TypeIdent("String")), Typed(Wildcard(), TypeIdent("Int")))), None, Block(Nil, Literal(UnitConstant()))))))
5656
TypeRef(ThisType(TypeRef(NoPrefix(), "scala")), "Unit")
5757

58-
Inlined(None, Nil, Match(Literal(StringConstant("h")), List(CaseDef(Ident("_"), Some(Literal(BooleanConstant(false))), Block(Nil, Literal(UnitConstant()))))))
58+
Inlined(None, Nil, Match(Literal(StringConstant("h")), List(CaseDef(Wildcard(), Some(Literal(BooleanConstant(false))), Block(Nil, Literal(UnitConstant()))))))
5959
TypeRef(ThisType(TypeRef(NoPrefix(), "scala")), "Unit")
6060

61-
Inlined(None, Nil, Block(List(ValDef("a", Inferred(), Some(Literal(StringConstant("o"))))), Match(Literal(StringConstant("i")), List(CaseDef(Bind("a", Ident("_")), None, Block(Nil, Literal(UnitConstant())))))))
61+
Inlined(None, Nil, Block(List(ValDef("a", Inferred(), Some(Literal(StringConstant("o"))))), Match(Literal(StringConstant("i")), List(CaseDef(Bind("a", Wildcard()), None, Block(Nil, Literal(UnitConstant())))))))
6262
TypeRef(ThisType(TypeRef(NoPrefix(), "scala")), "Unit")
6363

64-
Inlined(None, Nil, Match(Ident("Nil"), List(CaseDef(Unapply(TypeApply(Select(Ident("List"), "unapplySeq"), List(Inferred())), Nil, List(Bind("a", Ident("_")), Bind("b", Ident("_")), Bind("c", Ident("_")))), None, Block(Nil, Literal(UnitConstant()))))))
64+
Inlined(None, Nil, Match(Ident("Nil"), List(CaseDef(Unapply(TypeApply(Select(Ident("List"), "unapplySeq"), List(Inferred())), Nil, List(Bind("a", Wildcard()), Bind("b", Wildcard()), Bind("c", Wildcard()))), None, Block(Nil, Literal(UnitConstant()))))))
6565
TypeRef(ThisType(TypeRef(NoPrefix(), "scala")), "Unit")
6666

67-
Inlined(None, Nil, Try(Literal(IntConstant(1)), List(CaseDef(Ident("_"), None, Block(Nil, Literal(UnitConstant())))), None))
67+
Inlined(None, Nil, Try(Literal(IntConstant(1)), List(CaseDef(Wildcard(), None, Block(Nil, Literal(UnitConstant())))), None))
6868
OrType(ConstantType(IntConstant(1)), TypeRef(ThisType(TypeRef(NoPrefix(), "scala")), "Unit"))
6969

7070
Inlined(None, Nil, Try(Literal(IntConstant(2)), Nil, Some(Literal(UnitConstant()))))
7171
ConstantType(IntConstant(2))
7272

73-
Inlined(None, Nil, Try(Literal(IntConstant(3)), List(CaseDef(Ident("_"), None, Block(Nil, Literal(UnitConstant())))), Some(Literal(UnitConstant()))))
73+
Inlined(None, Nil, Try(Literal(IntConstant(3)), List(CaseDef(Wildcard(), None, Block(Nil, Literal(UnitConstant())))), Some(Literal(UnitConstant()))))
7474
OrType(ConstantType(IntConstant(3)), TypeRef(ThisType(TypeRef(NoPrefix(), "scala")), "Unit"))
7575

7676
Inlined(None, Nil, Literal(BooleanConstant(false)))

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