From b80a89e36d5dc62c49ccfd975756c9583949c69c Mon Sep 17 00:00:00 2001
From: Valentin Fondaratov <valentin.fondaratov@jetbrains.com>
Date: Tue, 3 Oct 2017 15:12:39 +0300
Subject: [PATCH] fix too strict hints offset condition

Required for RUBY-20196, see `ParamHintsTest.testRestAndBlock`
---
 .../codeInsight/hints/ParameterHintsPass.java | 19 +++++++++++++++++--
 1 file changed, 17 insertions(+), 2 deletions(-)

diff --git a/platform/lang-impl/src/com/intellij/codeInsight/hints/ParameterHintsPass.java b/platform/lang-impl/src/com/intellij/codeInsight/hints/ParameterHintsPass.java
index 2c04f53821d6..e179b586c1a0 100644
--- a/platform/lang-impl/src/com/intellij/codeInsight/hints/ParameterHintsPass.java
+++ b/platform/lang-impl/src/com/intellij/codeInsight/hints/ParameterHintsPass.java
@@ -94,8 +94,8 @@ public class ParameterHintsPass extends EditorBoundHighlightingPass {
 
     inlays.forEach((hint) -> {
       int offset = hint.getOffset();
-      TextRange rootRange = myRootElement.getTextRange();
-      if (offset <= rootRange.getStartOffset() || offset >= rootRange.getEndOffset()) return;
+      if (!canShowHintsAtOffset(offset)) return;
+
       String presentation = provider.getInlayPresentation(hint.getText());
       if (hint.isShowOnlyIfExistedBefore()) {
         myShowOnlyIfExistedBeforeHints.put(offset, presentation);
@@ -138,6 +138,21 @@ public class ParameterHintsPass extends EditorBoundHighlightingPass {
 
     return ContainerUtil.filter(inlays, (hint) -> manager.isParameterHint(hint));
   }
+
+  /**
+   * Adding hints on the borders of root element (at startOffset or endOffset)
+   * is allowed only in the case when root element is a document
+   *
+   * @return true iff a given offset can be used for hint rendering
+   */
+  private boolean canShowHintsAtOffset(int offset) {
+    TextRange rootRange = myRootElement.getTextRange();
+
+    if (!rootRange.containsOffset(offset)) return false;
+    if (offset > rootRange.getStartOffset() && offset < rootRange.getEndOffset()) return true;
+
+    return myDocument != null && myDocument.getTextLength() == rootRange.getLength();
+  }
   
   public static class HintData {
     public final String presentationText;