Merge pull request #3166 from skyluc/issue/completion-import-object-7280-210

Backport of 

5 files changed, 100 insertions, 37 deletions

diff --git a/src/compiler/scala/tools/nsc/interactive/ContextTrees.scala b/src/compiler/scala/tools/nsc/interactive/ContextTrees.scala
index b2568e34bd..4a61a98921 100644
--- a/src/compiler/scala/tools/nsc/interactive/ContextTrees.scala
+++ b/src/compiler/scala/tools/nsc/interactive/ContextTrees.scala
@@ -6,7 +6,7 @@ package scala.tools.nsc
 package interactive
 
 import scala.collection.mutable.ArrayBuffer
-import scala.reflect.internal.util.Position
+import scala.annotation.tailrec
 
 trait ContextTrees { self: Global =>
 
@@ -29,44 +29,59 @@ trait ContextTrees { self: Global =>
     override def toString = "ContextTree("+pos+", "+children+")"
   }
 
-  /** Optionally returns the smallest context that contains given `pos`, or None if none exists.
+  /** Returns the most precise context possible for the given `pos`.
+   *
+   *  It looks for the finest ContextTree containing `pos`, and then look inside
+   *  this ContextTree for a child ContextTree located immediately before `pos`.
+   *  If such a child exists, returns its context, otherwise returns the context of
+   *  the parent ContextTree.
+   *
+   *  This is required to always return a context which contains the all the imports
+   *  declared up to `pos` (see SI-7280 for a test case).
+   *
+   *  Can return None if `pos` is before any valid Scala code.
    */
   def locateContext(contexts: Contexts, pos: Position): Option[Context] = synchronized {
-    def locateNearestContextTree(contexts: Contexts, pos: Position, recent: Array[ContextTree]): Option[ContextTree] = {
-      locateContextTree(contexts, pos) match {
-        case Some(x) =>
-          recent(0) = x
-          locateNearestContextTree(x.children, pos, recent)
-        case None => recent(0) match {
-            case null => None
-            case x => Some(x)
-          }
+    @tailrec
+    def locateFinestContextTree(context: ContextTree): ContextTree = {
+      if (context.pos includes pos) {
+        locateContextTree(context.children, pos) match {
+          case Some(x) =>
+            locateFinestContextTree(x)
+          case None =>
+            context
+        }
+      } else {
+        context
       }
     }
-    locateNearestContextTree(contexts, pos, new Array[ContextTree](1)) map (_.context)
+    locateContextTree(contexts, pos) map locateFinestContextTree map (_.context)
   }
 
+  /** Returns the ContextTree containing `pos`, or the ContextTree positioned just before `pos`,
+   *  or None if `pos` is located before all ContextTrees.
+   */
   def locateContextTree(contexts: Contexts, pos: Position): Option[ContextTree] = {
     if (contexts.isEmpty) None
     else {
-      val hi = contexts.length - 1
-      if ((contexts(hi).pos properlyPrecedes pos) || (pos properlyPrecedes contexts(0).pos)) None
-      else {
-        def loop(lo: Int, hi: Int): Option[ContextTree] = {
+      @tailrec
+      def loop(lo: Int, hi: Int, previousSibling: Option[ContextTree]): Option[ContextTree] = {
+        if (pos properlyPrecedes contexts(lo).pos)
+          previousSibling
+        else if (contexts(hi).pos properlyPrecedes pos)
+          Some(contexts(hi))
+        else {
           val mid = (lo + hi) / 2
           val midpos = contexts(mid).pos
-          if ((pos precedes midpos) && (mid < hi))
-            loop(lo, mid)
-          else if ((midpos precedes pos) && (lo < mid))
-            loop(mid, hi)
-          else if (midpos includes pos)
+          if (midpos includes pos)
             Some(contexts(mid))
-          else if (contexts(mid+1).pos includes pos)
-            Some(contexts(mid+1))
-          else None
+          else if (midpos properlyPrecedes pos)
+            loop(mid + 1, hi, Some(contexts(mid)))
+          else
+            loop(lo, mid, previousSibling)
         }
-        loop(0, hi)
       }
+      loop(0, contexts.length - 1, None)
     }
   }
 
diff --git a/src/compiler/scala/tools/nsc/interactive/tests/InteractiveTest.scala b/src/compiler/scala/tools/nsc/interactive/tests/InteractiveTest.scala
index 597b9012ce..1c722ea3a0 100644
--- a/src/compiler/scala/tools/nsc/interactive/tests/InteractiveTest.scala
+++ b/src/compiler/scala/tools/nsc/interactive/tests/InteractiveTest.scala
@@ -69,7 +69,7 @@ abstract class InteractiveTest
    *  Override this member if you need to change the default set of executed test actions.
    */
   protected lazy val testActions: ListBuffer[PresentationCompilerTestDef] = {
-    ListBuffer(new CompletionAction(compiler), new TypeAction(compiler), new HyperlinkAction(compiler))
+    ListBuffer(new TypeCompletionAction(compiler), new ScopeCompletionAction(compiler), new TypeAction(compiler), new HyperlinkAction(compiler))
   }
 
   /** Add new presentation compiler actions to test. Presentation compiler's test
diff --git a/src/compiler/scala/tools/nsc/interactive/tests/core/AskCommand.scala b/src/compiler/scala/tools/nsc/interactive/tests/core/AskCommand.scala
index 8d446cbbf8..4f9df6808f 100644
--- a/src/compiler/scala/tools/nsc/interactive/tests/core/AskCommand.scala
+++ b/src/compiler/scala/tools/nsc/interactive/tests/core/AskCommand.scala
@@ -42,7 +42,7 @@ trait AskParse extends AskCommand {
   import compiler.Tree
 
   /** `sources` need to be entirely parsed before running the test
-   *  (else commands such as `AskCompletionAt` may fail simply because
+   *  (else commands such as `AskTypeCompletionAt` may fail simply because
    *  the source's AST is not yet loaded).
    */
   def askParse(sources: Seq[SourceFile]) {
@@ -72,10 +72,10 @@ trait AskReload extends AskCommand {
 }
 
 /** Ask the presentation compiler for completion at a given position. */
-trait AskCompletionAt extends AskCommand {
+trait AskTypeCompletionAt extends AskCommand {
   import compiler.Member
 
-  private[tests] def askCompletionAt(pos: Position)(implicit reporter: Reporter): Response[List[Member]] = {
+  private[tests] def askTypeCompletionAt(pos: Position)(implicit reporter: Reporter): Response[List[Member]] = {
     reporter.println("\naskTypeCompletion at " + pos.source.file.name + ((pos.line, pos.column)))
 
     ask {
@@ -84,6 +84,19 @@ trait AskCompletionAt extends AskCommand {
   }
 }
 
+/** Ask the presentation compiler for scope completion at a given position. */
+trait AskScopeCompletionAt extends AskCommand {
+  import compiler.Member
+
+  private[tests] def askScopeCompletionAt(pos: Position)(implicit reporter: Reporter): Response[List[Member]] = {
+    reporter.println("\naskScopeCompletion at " + pos.source.file.name + ((pos.line, pos.column)))
+
+    ask {
+      compiler.askScopeCompletion(pos, _)
+    }
+  }
+}
+
 /** Ask the presentation compiler for type info at a given position. */
 trait AskTypeAt extends AskCommand {
   import compiler.Tree
diff --git a/src/compiler/scala/tools/nsc/interactive/tests/core/CoreTestDefs.scala b/src/compiler/scala/tools/nsc/interactive/tests/core/CoreTestDefs.scala
index c8e6b6ccce..214f7a4553 100644
--- a/src/compiler/scala/tools/nsc/interactive/tests/core/CoreTestDefs.scala
+++ b/src/compiler/scala/tools/nsc/interactive/tests/core/CoreTestDefs.scala
@@ -13,19 +13,19 @@ private[tests] trait CoreTestDefs
 
   /** Ask the presentation compiler for completion at all locations
    * (in all sources) where the defined `marker` is found. */
-  class CompletionAction(override val compiler: Global)
+  class TypeCompletionAction(override val compiler: Global)
     extends PresentationCompilerTestDef
-    with AskCompletionAt {
+    with AskTypeCompletionAt {
 
     def memberPrinter(member: compiler.Member): String =
         "[accessible: %5s] ".format(member.accessible) + "`" + (member.sym.toString() + member.tpe.toString()).trim() + "`"
 
     override def runTest() {
-      askAllSources(CompletionMarker) { pos =>
-        askCompletionAt(pos)
+      askAllSources(TypeCompletionMarker) { pos =>
+        askTypeCompletionAt(pos)
       } { (pos, members) =>
         withResponseDelimiter {
-          reporter.println("[response] aksTypeCompletion at " + format(pos))
+          reporter.println("[response] askTypeCompletion at " + format(pos))
           // we skip getClass because it changed signature between 1.5 and 1.6, so there is no
           // universal check file that we can provide for this to work
           reporter.println("retrieved %d members".format(members.size))
@@ -38,6 +38,39 @@ private[tests] trait CoreTestDefs
     }
   }
 
+  /** Ask the presentation compiler for completion at all locations
+   * (in all sources) where the defined `marker` is found. */
+  class ScopeCompletionAction(override val compiler: Global)
+    extends PresentationCompilerTestDef
+    with AskScopeCompletionAt {
+
+    def memberPrinter(member: compiler.Member): String =
+        "[accessible: %5s] ".format(member.accessible) + "`" + (member.sym.toString() + member.tpe.toString()).trim() + "`"
+
+    override def runTest() {
+      askAllSources(ScopeCompletionMarker) { pos =>
+        askScopeCompletionAt(pos)
+      } { (pos, members) =>
+        withResponseDelimiter {
+          reporter.println("[response] askScopeCompletion at " + format(pos))
+          try {
+            // exclude members not from source (don't have position), for more focussed and self contained tests.
+            def eligible(sym: compiler.Symbol) = sym.pos != compiler.NoPosition
+            val filtered = members.filter(member => eligible(member.sym))
+            reporter.println("retrieved %d members".format(filtered.size))
+            compiler ask { () =>
+              reporter.println(filtered.map(memberPrinter).sortBy(_.toString()).mkString("\n"))
+            }
+          } catch {
+            case t: Throwable =>
+              t.printStackTrace()
+          }
+
+        }
+      }
+    }
+  }
+
   /** Ask the presentation compiler for type info at all locations
    * (in all sources) where the defined `marker` is found. */
   class TypeAction(override val compiler: Global)
@@ -61,7 +94,7 @@ private[tests] trait CoreTestDefs
   class HyperlinkAction(override val compiler: Global)
     extends PresentationCompilerTestDef
     with AskTypeAt
-    with AskCompletionAt {
+    with AskTypeCompletionAt {
 
     override def runTest() {
       askAllSources(HyperlinkMarker) { pos =>
@@ -97,4 +130,4 @@ private[tests] trait CoreTestDefs
       }
     }
   }
-}
\ No newline at end of file
+}
diff --git a/src/compiler/scala/tools/nsc/interactive/tests/core/TestMarker.scala b/src/compiler/scala/tools/nsc/interactive/tests/core/TestMarker.scala
index ba1722382b..8698ada4ad 100644
--- a/src/compiler/scala/tools/nsc/interactive/tests/core/TestMarker.scala
+++ b/src/compiler/scala/tools/nsc/interactive/tests/core/TestMarker.scala
@@ -20,7 +20,9 @@ abstract case class TestMarker(val marker: String) {
   TestMarker.checkForDuplicate(this)
 }
 
-object CompletionMarker extends TestMarker("/*!*/")
+object TypeCompletionMarker extends TestMarker("/*!*/")
+
+object ScopeCompletionMarker extends TestMarker("/*_*/")
 
 object TypeMarker extends TestMarker("/*?*/")