Prevent adaptations of extension method applications

odersky · odersky · commit 2662e6fc9bb5 · 2019-06-18T16:54:36.000+02:00
Prevent adaptations of extension method applications coming from implicit search.
We already did the same for extension method applications coming from imports.
diff --git a/compiler/src/dotty/tools/dotc/typer/Implicits.scala b/compiler/src/dotty/tools/dotc/typer/Implicits.scala
@@ -1348,7 +1348,10 @@ trait Implicits { self: Typer =>
       }
       else {
         val returned =
-          if (cand.isExtension) new Applications.ExtMethodApply(adapted).withType(adapted.tpe)
+          if (cand.isExtension)
+            new Applications.ExtMethodApply(adapted).withType(WildcardType)
+              // Use wildcard type in order not to prompt any further adaptations such as eta expansion
+              // before the method is fully applied.
           else adapted
         SearchSuccess(returned, ref, cand.level)(ctx.typerState, ctx.gadt)
       }

Original file line number	Diff line number	Diff line change
`@@ -1348,7 +1348,10 @@ trait Implicits { self: Typer =>`
`1348`	`1348`	`}`
`1349`	`1349`	`else {`
`1350`	`1350`	`val returned =`
`1351`		`- if (cand.isExtension) new Applications.ExtMethodApply(adapted).withType(adapted.tpe)`
	`1351`	`+ if (cand.isExtension)`
	`1352`	`+ new Applications.ExtMethodApply(adapted).withType(WildcardType)`
	`1353`	`+ // Use wildcard type in order not to prompt any further adaptations such as eta expansion`
	`1354`	`+ // before the method is fully applied.`
`1352`	`1355`	`else adapted`
`1353`	`1356`	`SearchSuccess(returned, ref, cand.level)(ctx.typerState, ctx.gadt)`
`1354`	`1357`	`}`