Avoid duplicating parameter names

odersky · odersky · commit f791a527d4bd · 2019-02-08T16:08:45.000+01:00
Avoid duplicating parameter names in derivations of n-ary type classes
diff --git a/compiler/src/dotty/tools/dotc/typer/Deriving.scala b/compiler/src/dotty/tools/dotc/typer/Deriving.scala
@@ -193,7 +193,7 @@ trait Deriving { this: Typer =>
           if (nparams == 0) Nil
           else if (nparams == 1) tparam :: Nil
           else typeClass.typeParams.map(tcparam =>
-            tparam.copy(name = s"${tparam.name}_${tcparam.name}".toTypeName)
+            tparam.copy(name = s"${tparam.name}_$$_${tcparam.name}".toTypeName)
               .asInstanceOf[TypeSymbol])
         }
         val firstKindedParamss = clsParamss.filter {

Original file line number	Diff line number	Diff line change
`@@ -193,7 +193,7 @@ trait Deriving { this: Typer =>`
`193`	`193`	`if (nparams == 0) Nil`
`194`	`194`	`else if (nparams == 1) tparam :: Nil`
`195`	`195`	`else typeClass.typeParams.map(tcparam =>`
`196`		`- tparam.copy(name = s"${tparam.name}_${tcparam.name}".toTypeName)`
	`196`	`+ tparam.copy(name = s"${tparam.name}_$$_${tcparam.name}".toTypeName)`
`197`	`197`	`.asInstanceOf[TypeSymbol])`
`198`	`198`	`}`
`199`	`199`	`val firstKindedParamss = clsParamss.filter {`