Make sure symbol is completed before taking extension parameter

Needed to make sure that rawParamss is set

Author: odersky

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

@@ -325,6 +325,7 @@ object SymDenotations {
         case _ =>
           Nil
 
+      ensureCompleted()
       if rawParamss.isEmpty then recurWithoutParamss(info)
       else recurWithParamss(info, rawParamss)
     end paramSymss
@@ -339,6 +340,7 @@ object SymDenotations {
         case (fst :: Nil) :: _ => fst
         case _ => NoSymbol
       assert(isAllOf(ExtensionMethod))
+      ensureCompleted()
       leadParam(rawParamss)
 
     /** The denotation is completed: info is not a lazy type and attributes have defined values */

tests/run/collective-extensions.scala

@@ -7,8 +7,9 @@ extension (x: String)
   def bam(y: String): String = this.baz(x)(y)
   def ban(foo: String): String = x + foo
   def bao(y: String): String =
-    val bam = "ABC"
+    val bam = name
     x ++ y ++ bam
+  def name: String = "ABC"
 
   def app(n: Int, suffix: String): String =
     if n == 0 then x ++ suffix