Extract name kind from ERROR

The parser tells us whether the error happened in term or type position,
so we can use this to provide better completion.

Author: Duhemm

compiler/src/dotty/tools/dotc/interactive/Completion.scala

@@ -11,7 +11,7 @@ import dotty.tools.dotc.core.NameKinds.SimpleNameKind
 import dotty.tools.dotc.core.NameOps.NameDecorator
 import dotty.tools.dotc.core.Symbols.{defn, NoSymbol, Symbol}
 import dotty.tools.dotc.core.Scopes
-import dotty.tools.dotc.core.StdNames.nme
+import dotty.tools.dotc.core.StdNames.{nme, tpnme}
 import dotty.tools.dotc.core.TypeError
 import dotty.tools.dotc.core.Types.{NamedType, NameFilter, Type, takeAllFilter}
 import dotty.tools.dotc.printing.Texts._
@@ -45,7 +45,8 @@ object Completion {
   private def completionMode(path: List[Tree], pos: SourcePosition): Mode = {
     path match {
       case (ref: RefTree) :: _ =>
-        if (ref.name == nme.ERROR) Mode.Term | Mode.Type
+        if (ref.name == tpnme.ERROR) Mode.Type
+        else if (ref.name == nme.ERROR) Mode.Term
         else if (ref.name.isTermName) Mode.Term
         else if (ref.name.isTypeName) Mode.Type
         else Mode.None

language-server/test/dotty/tools/languageserver/CompletionTest.scala

@@ -175,4 +175,17 @@ class CompletionTest {
           |}""".withSource
       .completion(m1, results => assertTrue(results.nonEmpty))
   }
+
+  @Test def completeErrorKnowsKind: Unit = {
+    code"""object Bar {
+          |  class Zig
+          |  val Zag: Int = 0
+          |  val b = 3 + Bar.${m1}
+          |}""".withSource
+      .completion(m1, completionItems => {
+        val results = CodeCompletion.simplifyResults(completionItems)
+        assertTrue(results.contains(("Zag", Field, "Int")))
+        assertFalse(results.exists((label, _, _) => label == "Zig"))
+      })
+  }
 }