1 files changed, 20 insertions, 5 deletions

diff --git a/platform/lang-impl/src/com/intellij/lang/parser/GeneratedParserUtilBase.java b/platform/lang-impl/src/com/intellij/lang/parser/GeneratedParserUtilBase.java
index ecda31db8355..ad322c232fa0 100644
--- a/platform/lang-impl/src/com/intellij/lang/parser/GeneratedParserUtilBase.java
+++ b/platform/lang-impl/src/com/intellij/lang/parser/GeneratedParserUtilBase.java
@@ -2,6 +2,7 @@
 // Do not modify or refactor without complete investigation and/or review.
 package com.intellij.lang.parser;
 
+import com.intellij.codeInsight.completion.impl.CamelHumpMatcher;
 import com.intellij.lang.*;
 import com.intellij.lang.impl.PsiBuilderAdapter;
 import com.intellij.lang.impl.PsiBuilderImpl;
@@ -337,18 +338,18 @@ public class GeneratedParserUtilBase {
     }
     else if (diff > 0 && diff <= length) {
       CharSequence fragment = builder_.getOriginalText().subSequence(offset, completionState.offset);
-      add = StringUtil.startsWithIgnoreCase(text, fragment.toString());
+      add = completionState.prefixMatches(fragment.toString(), text);
     }
     else if (diff < 0) {
       for (int i=-1; ; i--) {
         IElementType type = builder_.rawLookup(i);
         int tokenStart = builder_.rawTokenTypeStart(i);
-        if (((PsiBuilderImpl)((Builder)builder_).getDelegate()).whitespaceOrComment(type)) {
+        if (isWhitespaceOrComment(builder_, type)) {
           diff = completionState.offset - tokenStart;
         }
         else if (type != null && tokenStart < completionState.offset) {
           CharSequence fragment = builder_.getOriginalText().subSequence(tokenStart, completionState.offset);
-          if (StringUtil.startsWithIgnoreCase(text, fragment.toString())) {
+          if (completionState.prefixMatches(fragment.toString(), text)) {
             diff = completionState.offset - tokenStart;
           }
           break;
@@ -364,6 +365,10 @@ public class GeneratedParserUtilBase {
     }
   }
 
+  public static boolean isWhitespaceOrComment(@NotNull PsiBuilder builder_, @Nullable IElementType type) {
+    return ((PsiBuilderImpl)((Builder)builder_).getDelegate()).whitespaceOrComment(type);
+  }
+
   // here's the new section API for compact parsers & less IntelliJ platform API exposure
   public static final int _NONE_       = 0x0;
   public static final int _COLLAPSE_   = 0x1;
@@ -514,7 +519,9 @@ public class GeneratedParserUtilBase {
     }
     // propagate errorReportedAt up the stack to avoid duplicate reporting
     Frame prevFrame = willFail && eatMore == null ? null : state.frameStack.peekLast();
-    if (prevFrame != null && prevFrame.errorReportedAt < frame.errorReportedAt) prevFrame.errorReportedAt = frame.errorReportedAt;
+    if (prevFrame != null && prevFrame.errorReportedAt < frame.errorReportedAt) {
+      prevFrame.errorReportedAt = frame.errorReportedAt;
+    }
     state.FRAMES.recycle(frame);
   }
 
@@ -657,9 +664,17 @@ public class GeneratedParserUtilBase {
       return o.toString();
     }
 
-    public void addItem(PsiBuilder builder, String text) {
+    public void addItem(@NotNull PsiBuilder builder, @NotNull String text) {
       items.add(text);
     }
+
+    public boolean prefixMatches(@NotNull String prefix, @NotNull String variant) {
+      boolean matches = new CamelHumpMatcher(prefix, false).prefixMatches(variant.replace(' ', '_'));
+      if (matches && StringUtil.isWhiteSpace(prefix.charAt(prefix.length() - 1))) {
+        return StringUtil.startsWithIgnoreCase(variant, prefix);
+      }
+      return matches;
+    }
   }
 
   public static class Builder extends PsiBuilderAdapter {