From bcbfa2b869ea584f1fa0e2664eba857316ff7e02 Mon Sep 17 00:00:00 2001
From: Rik van der Kleij <rikvdkleij@gmail.com>
Date: Thu, 3 Oct 2019 15:41:10 +0200
Subject: [PATCH] Improve code completion and fix issue #470

---
 .../haskell/editor/HaskellCompletionContributor.scala    | 9 ++++-----
 src/main/scala/intellij/haskell/psi/HaskellPsiUtil.scala | 7 +++++++
 2 files changed, 11 insertions(+), 5 deletions(-)

diff --git a/src/main/scala/intellij/haskell/editor/HaskellCompletionContributor.scala b/src/main/scala/intellij/haskell/editor/HaskellCompletionContributor.scala
index b5c2a471..0b9b85b4 100644
--- a/src/main/scala/intellij/haskell/editor/HaskellCompletionContributor.scala
+++ b/src/main/scala/intellij/haskell/editor/HaskellCompletionContributor.scala
@@ -45,7 +45,7 @@ class HaskellCompletionContributor extends CompletionContributor {
 
   private final val HaskellWhere = LazyList("where")
   private final val HaskellLet = LazyList("let")
-  private final val haskellDeclKeywords = LazyList("family", "data", "type", "module", "class", "instance", "newtype", "deriving", "in")
+  private final val haskellDeclarationKeywords = LazyList("family", "data", "type", "module", "class", "instance", "newtype", "deriving", "in")
   private final val HaskellDefault = LazyList("default")
   private final val HaskellImportKeywords = LazyList("import", "qualified", "as", "hiding")
   private final val HaskellForeignKeywords = LazyList("foreign", "export", "ccall", "safe", "unsafe", "interruptible", "capi", "prim")
@@ -60,7 +60,7 @@ class HaskellCompletionContributor extends CompletionContributor {
   private final val HaskellRecursiveDo = LazyList("mdo", "rec")
   private final val HaskellArrowSyntax = LazyList("proc")
 
-  private final val Keywords = HaskellWhere ++ HaskellLet ++ haskellDeclKeywords ++ HaskellDefault ++ HaskellImportKeywords ++
+  private final val Keywords = HaskellWhere ++ HaskellLet ++ haskellDeclarationKeywords ++ HaskellDefault ++ HaskellImportKeywords ++
     HaskellForeignKeywords ++ HaskellKeyword ++ HaskellStatic ++ HaskellConditional ++ HaskellInfix ++ HaskellBottom ++
     HaskellTodo ++ HaskellTypeRoles ++ HaskellForall ++ HaskellRecursiveDo ++ HaskellArrowSyntax
 
@@ -127,7 +127,7 @@ class HaskellCompletionContributor extends CompletionContributor {
         val prefixText = (
           for {
             e <- positionElement
-            mie <- HaskellPsiUtil.findModIdElement(e)
+            mie <- HaskellPsiUtil.findModIdElement(e).orElse(HaskellPsiUtil.findQualifierElement(e))
             start = mie.getTextRange.getStartOffset
             end = parameters.getOffset
           } yield psiFile.getText.substring(start, end)
@@ -231,8 +231,7 @@ class HaskellCompletionContributor extends CompletionContributor {
     def addCompletions(parameters: CompletionParameters, context: ProcessingContext, originalResultSet: CompletionResultSet): Unit = {
       ProgressManager.checkCanceled()
 
-      val project = parameters.getOriginalPosition.getProject
-
+      val project = parameters.getOriginalFile.getProject
       if (StackProjectManager.isInitializing(project)) {
         HaskellEditorUtil.showHaskellSupportIsNotAvailableWhileInitializing(project)
       } else {
diff --git a/src/main/scala/intellij/haskell/psi/HaskellPsiUtil.scala b/src/main/scala/intellij/haskell/psi/HaskellPsiUtil.scala
index 350d6733..4cb2f34e 100644
--- a/src/main/scala/intellij/haskell/psi/HaskellPsiUtil.scala
+++ b/src/main/scala/intellij/haskell/psi/HaskellPsiUtil.scala
@@ -58,6 +58,13 @@ object HaskellPsiUtil {
     }
   }
 
+  def findQualifierElement(psiElement: PsiElement): Option[HaskellQualifier] = {
+    psiElement match {
+      case e: HaskellQualifier => Some(e)
+      case e => Option(TreeUtil.findParent(e.getNode, HaskellTypes.HS_QUALIFIER)).map(_.getPsi.asInstanceOf[HaskellQualifier])
+    }
+  }
+
   def findDataConstr(psiElement: PsiElement): Option[HaskellConstr] = {
     psiElement match {
       case e: HaskellConstr => Some(e)