Typecheck usecases

Author: felixmulder

src/dotty/tools/dotc/typer/Namer.scala

@@ -426,7 +426,14 @@ class Namer { typer: Typer =>
   }
 
   def setDocstring(sym: Symbol, tree: Tree)(implicit ctx: Context) = tree match {
-    case t: MemberDef => ctx.docbase.addDocstring(sym, t.rawComment)
+    case t: MemberDef if t.rawComment.isDefined =>
+      val cmt = t.rawComment
+      ctx.docbase.addDocstring(sym, cmt)
+
+      cmt.get.usecases.foreach { usecase =>
+        usecase.symbol = enterSymbol(createSymbol(usecase.untpdCode))
+      }
+
     case _ => ()
   }
 

src/dotty/tools/dotc/typer/Typer.scala

@@ -1119,6 +1119,10 @@ class Typer extends Namer with TypeAssigner with Applications with Implicits wit
       // function types so no dependencies on parameters are allowed.
       tpt1 = tpt1.withType(avoid(tpt1.tpe, vparamss1.flatMap(_.map(_.symbol))))
     }
+
+    /** Type usecases */
+    ctx.docbase.docstring(sym).map(_.usecases.map(_.typeTree()))
+
     assignType(cpy.DefDef(ddef)(name, tparams1, vparamss1, tpt1, rhs1), sym)
     //todo: make sure dependent method types do not depend on implicits or by-name params
   }