Add MethodType.nonErasedParamCount

Author: nicolasstucki

compiler/src/dotty/tools/dotc/core/TypeErasure.scala

@@ -567,7 +567,7 @@ object TypeErasure {
         functionType(info.resultType)
       case info: MethodType =>
         assert(!info.resultType.isInstanceOf[MethodicType])
-        defn.FunctionType(n = info.erasedParams.count(_ == false))
+        defn.FunctionType(n = info.nonErasedParamCount)
     }
     erasure(functionType(applyInfo))
 }

compiler/src/dotty/tools/dotc/core/Types.scala

@@ -4021,6 +4021,10 @@ object Types {
     override def erasedParams(using Context): List[Boolean] =
       paramInfos.map(p => p.hasAnnotation(defn.ErasedParamAnnot))
 
+    def nonErasedParamCount(using Context): Int =
+      paramInfos.count(p => !p.hasAnnotation(defn.ErasedParamAnnot))
+
+
     protected def prefixString: String = companion.prefixString
   }
 

compiler/src/dotty/tools/dotc/transform/ContextFunctionResults.scala

@@ -85,13 +85,13 @@ object ContextFunctionResults:
       else
         val defn.ContextFunctionType(params, resTpe, erasedParams) = tp: @unchecked
         val rest = contextParamCount(resTpe, crCount - 1)
-        if erasedParams.contains(true) then erasedParams.count(_ == false) + rest else params.length + rest
+        if erasedParams.contains(true) then erasedParams.count(_ == false) + rest else params.length + rest // TODO use mt.nonErasedParamCount
 
     def normalParamCount(tp: Type): Int = tp.widenExpr.stripPoly match
       case mt @ MethodType(pnames) =>
         val rest = normalParamCount(mt.resType)
         if mt.hasErasedParams then
-          mt.erasedParams.count(_ == false) + rest
+          mt.nonErasedParamCount + rest
         else pnames.length + rest
       case _ => contextParamCount(tp, contextResultCount(sym))