Add type params to type aliases

7 files changed, 35 insertions, 17 deletions

diff --git a/doc-tool/resources/_layouts/api-page.html b/doc-tool/resources/_layouts/api-page.html
index 878ec8d8f..2d2f0265a 100644
--- a/doc-tool/resources/_layouts/api-page.html
+++ b/doc-tool/resources/_layouts/api-page.html
@@ -134,12 +134,25 @@ extraCSS:
                     {% endfor %}
                 {% endif %}
 
-                {% if member.kind == "type" and member.alias != null %}
+                {% if member.kind == "type" %}
+                {% for tparam in member.typeParams %}
+                    {% if forloop.first %}
+                        <span class="no-left">[</span>
+                    {% endif %}
+                    {% if forloop.last %}
+                        <span class="no-left">{{ tparam }}</span>
+                        <span class="no-left">]</span>
+                    {% else %}
+                        <span class="no-left">{{ tparam }}, </span>
+                    {% endif %}
+                {% endfor %}
+                {% if member.alias != null %}
                 <span class="type-alias">
                     <span class="equals"> = </span>
                     {% renderRef member.alias %}
                 </span>
                 {% endif %}
+                {% endif %}
 
                 {% if member.returnValue %}
                 <span class="no-left">: {% renderRef member.returnValue %}</span>
diff --git a/doc-tool/src/dotty/tools/dottydoc/core/DocASTPhase.scala b/doc-tool/src/dotty/tools/dottydoc/core/DocASTPhase.scala
index 7f44c5656..cfb66fa56 100644
--- a/doc-tool/src/dotty/tools/dottydoc/core/DocASTPhase.scala
+++ b/doc-tool/src/dotty/tools/dottydoc/core/DocASTPhase.scala
@@ -8,7 +8,7 @@ import dotc.CompilationUnit
 import dotc.config.Printers.dottydoc
 import dotc.core.Contexts.Context
 import dotc.core.Comments.ContextDocstrings
-import dotc.core.Types.NoType
+import dotc.core.Types.{PolyType, NoType}
 import dotc.core.Phases.Phase
 import dotc.core.Symbols.{ Symbol, NoSymbol }
 
@@ -92,8 +92,16 @@ class DocASTPhase extends Phase {
         val sym = t.symbol
         if (sym.is(Flags.Synthetic | Flags.Param))
           NonEntity
-        else
-          TypeAliasImpl(sym, annotations(sym), flags(t), t.name.show.split("\\$\\$").last, path(sym), alias(t.rhs.tpe))
+        else {
+          val tparams = t.rhs.tpe match {
+            case tp: PolyType => tp.paramRefs.zip(tp.variances).map { case (tp, variance) =>
+              val varianceSym = if (variance == 1) "+" else if (variance == -1) "-" else ""
+              varianceSym + tp.paramName.show
+            }
+            case _ => Nil
+          }
+          TypeAliasImpl(sym, annotations(sym), flags(t), t.name.show.split("\\$\\$").last, path(sym), alias(t.rhs.tpe), tparams)
+        }
 
       /** trait */
       case t @ TypeDef(n, rhs) if t.symbol.is(Flags.Trait) =>
diff --git a/doc-tool/src/dotty/tools/dottydoc/core/transform.scala b/doc-tool/src/dotty/tools/dottydoc/core/transform.scala
index e4b9ae6b6..5174c0922 100644
--- a/doc-tool/src/dotty/tools/dottydoc/core/transform.scala
+++ b/doc-tool/src/dotty/tools/dottydoc/core/transform.scala
@@ -92,6 +92,7 @@ object transform {
             t.name,
             t.path,
             t.alias,
+            t.typeParams,
             t.comment,
             t.parent
           )
diff --git a/doc-tool/src/dotty/tools/dottydoc/model/JavaConverters.scala b/doc-tool/src/dotty/tools/dottydoc/model/JavaConverters.scala
index 239656141..4a9bfce0c 100644
--- a/doc-tool/src/dotty/tools/dottydoc/model/JavaConverters.scala
+++ b/doc-tool/src/dotty/tools/dottydoc/model/JavaConverters.scala
@@ -189,6 +189,7 @@ object JavaConverters {
       "name" -> ent.name,
       "path" -> ent.path.asJava,
       "alias" -> ent.alias.map(_.asJava).asJava,
+      "typeParams" -> ent.typeParams.asJava,
       "comment" -> ent.comment.map(_.asJava).asJava,
       "hasShortenedDocstring" -> ent.hasShortenedDocstring,
       "isPrivate" -> ent.isPrivate,
diff --git a/doc-tool/src/dotty/tools/dottydoc/model/entities.scala b/doc-tool/src/dotty/tools/dottydoc/model/entities.scala
index d35077816..d0f1a82c7 100644
--- a/doc-tool/src/dotty/tools/dottydoc/model/entities.scala
+++ b/doc-tool/src/dotty/tools/dottydoc/model/entities.scala
@@ -108,7 +108,7 @@ trait Package extends Entity with Members with SuperTypes {
   val kind = "package"
 }
 
-trait TypeAlias extends Entity with Modifiers {
+trait TypeAlias extends Entity with Modifiers with TypeParams {
   val kind = "type"
   def alias: Option[Reference]
   def isAbstract: Boolean = !alias.isDefined
diff --git a/doc-tool/src/dotty/tools/dottydoc/model/factories.scala b/doc-tool/src/dotty/tools/dottydoc/model/factories.scala
index 568b532b7..3e766a990 100644
--- a/doc-tool/src/dotty/tools/dottydoc/model/factories.scala
+++ b/doc-tool/src/dotty/tools/dottydoc/model/factories.scala
@@ -4,7 +4,8 @@ package model
 import comment._
 import references._
 import dotty.tools.dotc
-import dotc.core.Types._
+import dotc.core.Types
+import Types._
 import dotc.core.TypeApplications._
 import dotc.core.Contexts.Context
 import dotc.core.Symbols.{ Symbol, ClassSymbol }
@@ -105,17 +106,8 @@ object factories {
       case ci: ClassInfo =>
         typeRef(ci.cls.name.show, query = ci.typeSymbol.showFullName)
 
-      case tl: PolyType => {
-        // FIXME: should be handled correctly
-        // example, in `Option`:
-        //
-        // ```scala
-        // def companion: GenericCompanion[collection.Iterable]
-        // ```
-        //
-        // Becomes: def companion: [+X0] -> collection.Iterable[X0]
-        typeRef(tl.show + " (not handled)")
-      }
+      case tl: PolyType =>
+        expandTpe(tl.resType)
 
       case OrType(left, right) =>
         OrTypeReference(expandTpe(left), expandTpe(right))
@@ -148,6 +140,8 @@ object factories {
             prefix + tp.name.show.split("\\$").last
           }
           .toList
+      case tp: Types.TypeAlias =>
+        typeParams(tp.alias.typeSymbol)
       case _ =>
         Nil
     }
diff --git a/doc-tool/src/dotty/tools/dottydoc/model/internal.scala b/doc-tool/src/dotty/tools/dottydoc/model/internal.scala
index bf50c0232..b50c93ee5 100644
--- a/doc-tool/src/dotty/tools/dottydoc/model/internal.scala
+++ b/doc-tool/src/dotty/tools/dottydoc/model/internal.scala
@@ -31,6 +31,7 @@ object internal {
     name: String,
     path: List[String],
     alias: Option[Reference],
+    typeParams: List[String] = Nil,
     var comment: Option[Comment] = None,
     var parent: Entity = NonEntity
   ) extends TypeAlias