Merge pull request #10531 from dotty-staging/fix-#10464

Fix #10464: Match overridden definitions

Author: nicolasstucki

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

@@ -101,7 +101,7 @@ object Matcher {
     // TODO improve performance
 
     // TODO use flag from qctx.reflect. Maybe -debug or add -debug-macros
-    private final val debug = false
+    private inline val debug = false
 
     import qctx.reflect._
     import Matching._
@@ -231,7 +231,7 @@ object Matcher {
             scrutinee =?= expr2
 
           /* Match selection */
-          case (ref: Ref, Select(qual2, _)) if scrutinee.symbol == pattern.symbol || summon[Env].get(scrutinee.symbol).contains(pattern.symbol) =>
+          case (ref: Ref, Select(qual2, _)) if symbolMatch(scrutinee.symbol, pattern.symbol) =>
             ref match
               case Select(qual1, _) => qual1 =?= qual2
               case ref: Ident =>
@@ -240,7 +240,7 @@ object Matcher {
                   case _ => matched
 
           /* Match reference */
-          case (_: Ref, _: Ident) if scrutinee.symbol == pattern.symbol || summon[Env].get(scrutinee.symbol).contains(pattern.symbol) =>
+          case (_: Ref, _: Ident) if symbolMatch(scrutinee.symbol, pattern.symbol) =>
             matched
 
           /* Match application */
@@ -329,23 +329,30 @@ object Matcher {
                 s""">>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
                    |Scrutinee
                    |  ${scrutinee.show}
-                   |
-                   |${scrutinee.showExtractors}
-                   |
                    |did not match pattern
                    |  ${pattern.show}
                    |
-                   |${pattern.showExtractors}
-                   |
                    |with environment: ${summon[Env]}
                    |
+                   |Scrutinee: ${scrutinee.showExtractors}
+                   |Pattern: ${pattern.showExtractors}
                    |
                    |""".stripMargin)
             notMatched
         }
       }
     end extension
 
+    /** Does the scrutenne symbol match the pattern symbol? It matches if:
+     *   - They are the same symbol
+     *   - The scrutinee has is in the environment and they are equivalent
+     *   - The scrutinee overrides the symbol of the pattern
+     */
+    private def symbolMatch(scrutinee: Symbol, pattern: Symbol)(using Env): Boolean =
+      scrutinee == pattern
+      || summon[Env].get(scrutinee).contains(pattern)
+      || scrutinee.allOverriddenSymbols.contains(pattern)
+
     private object ClosedPatternTerm {
       /** Matches a term that does not contain free variables defined in the pattern (i.e. not defined in `Env`) */
       def unapply(term: Term)(using Env): Option[term.type] =

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

@@ -2348,6 +2348,7 @@ class QuotesImpl private (using val ctx: Context) extends Quotes, QuoteUnpickler
 
         def paramSymss: List[List[Symbol]] = self.denot.paramSymss
         def primaryConstructor: Symbol = self.denot.primaryConstructor
+        def allOverriddenSymbols: Iterator[Symbol] = self.denot.allOverriddenSymbols
 
         def caseFields: List[Symbol] =
           if !self.isClass then Nil

library/src/scala/quoted/Quotes.scala

@@ -3625,6 +3625,9 @@ trait Quotes { self: runtime.QuoteUnpickler & runtime.QuoteMatching =>
           */
         def paramSymss: List[List[Symbol]]
 
+        /** Returns all symbols overridden by this symbol. */
+        def allOverriddenSymbols: Iterator[Symbol]
+
         /** The primary constructor of a class or trait, `noSymbol` if not applicable. */
         def primaryConstructor: Symbol
 

tests/run-macros/i10464.check

@@ -0,0 +1,5 @@
+matched!
+matched!
+matched!
+not matched
+not matched

tests/run-macros/i10464/Macro_1.scala

@@ -0,0 +1,16 @@
+import scala.quoted._
+
+object MatchMac {
+
+    inline def apply(inline any: Any): Unit = ${ printMacImpl('any) }
+
+    def printMacImpl(any: Expr[Any])(using Quotes): Expr[Unit] = {
+      import quotes.reflect._
+      val res = any match {
+        case '{ ($f: Person).name } => "matched!"
+        case _ => "not matched"
+      }
+      '{ println(${Expr(res)}) }
+    }
+
+}

tests/run-macros/i10464/Person_1.scala

@@ -0,0 +1,5 @@
+trait Person:
+  def name: String
+
+case class PersonA(name: String) extends Person
+case class PersonB(name: String) extends Person

tests/run-macros/i10464/Test_2.scala

@@ -0,0 +1,11 @@
+
+@main def Test = {
+  val personA: PersonA = PersonA("JoeA")
+  val personB: PersonB = PersonB("JoeB")
+  val person: Person = personA
+  MatchMac(personA.name)
+  MatchMac(personB.name)
+  MatchMac(person.name)
+  MatchMac(PersonA("JoeA").name) // optimized to MatchMac("JoeA")
+  MatchMac(PersonB("JoeB").name) // optimized to MatchMac("JoeB")
+}