Fix ranking logic

odersky · odersky · commit e491c87198a1 · 2024-08-05T23:57:48.000+02:00
diff --git a/compiler/src/dotty/tools/dotc/typer/Implicits.scala b/compiler/src/dotty/tools/dotc/typer/Implicits.scala
@@ -1368,9 +1368,9 @@ trait Implicits:
                       |Previous choice          : ${choice(prev)}
                       |New choice from Scala 3.7: ${choice(cmp)}""")
                 cmp
-            else cmp max prev
-              // When ranking, we keep the better of cmp and prev, which ends up retaining a candidate
-              // if it is retained in either version.
+            else if cmp != prev then
+              0 // When ranking, we retain a candidate if it is retained in either version.
+            else cmp
           else cmp
       end compareAlternatives
 
diff --git a/tests/pos/i15264.scala b/tests/pos/i15264.scala
@@ -1,3 +1,4 @@
+import language.`3.7`
 object priority:
     // lower number = higher priority
     class Prio0 extends Prio1

Original file line number	Diff line number	Diff line change
`@@ -1,3 +1,4 @@`
	`1`	+import language.`3.7`
`1`	`2`	`object priority:`
`2`	`3`	`// lower number = higher priority`
`3`	`4`	`class Prio0 extends Prio1`