From f51943380f9fe117dcbb92c24568335a909a59bb Mon Sep 17 00:00:00 2001
From: Dmitry Jemerov <yole@jetbrains.com>
Date: Thu, 13 Dec 2012 20:56:31 +0100
Subject: [PATCH] parse ellipsis only in the context where it can actually be
 used (PY-7763)

---
 .../python/parsing/ExpressionParsing.java     | 30 ++++++++++-------
 python/testData/psi/EllipsisAsStatement.py    |  5 +++
 python/testData/psi/EllipsisAsStatement.txt   | 33 +++++++++++++++++++
 .../jetbrains/python/PythonParsingTest.java   |  4 +++
 4 files changed, 61 insertions(+), 11 deletions(-)
 create mode 100644 python/testData/psi/EllipsisAsStatement.py
 create mode 100644 python/testData/psi/EllipsisAsStatement.txt

diff --git a/python/src/com/jetbrains/python/parsing/ExpressionParsing.java b/python/src/com/jetbrains/python/parsing/ExpressionParsing.java
index 47971220e18e..31681c8375e9 100644
--- a/python/src/com/jetbrains/python/parsing/ExpressionParsing.java
+++ b/python/src/com/jetbrains/python/parsing/ExpressionParsing.java
@@ -72,15 +72,6 @@ public class ExpressionParsing extends Parsing {
       parseReprExpression(myBuilder);
       return true;
     }
-    else if (firstToken == PyTokenTypes.DOT) {
-      final PsiBuilder.Marker maybeEllipsis = myBuilder.mark();
-      myBuilder.advanceLexer();
-      if (matchToken(PyTokenTypes.DOT) && matchToken(PyTokenTypes.DOT)) {
-        maybeEllipsis.done(PyElementTypes.NONE_LITERAL_EXPRESSION);
-        return true;
-      }
-      maybeEllipsis.rollbackTo();
-    }
     return false;
   }
 
@@ -334,7 +325,9 @@ public class ExpressionParsing extends Parsing {
             parseSliceEnd(expr, sliceItemStart);
           }
           else {
-            parseSingleExpression(false);
+            if (!parseEllipsis()) {
+              parseSingleExpression(false);
+            }
             if (atToken(PyTokenTypes.COLON)) {
               sliceOrTupleStart.drop();
               parseSliceEnd(expr, sliceItemStart);
@@ -378,6 +371,19 @@ public class ExpressionParsing extends Parsing {
     return true;
   }
 
+  private boolean parseEllipsis() {
+    if (atToken(PyTokenTypes.DOT)) {
+      final PsiBuilder.Marker maybeEllipsis = myBuilder.mark();
+      myBuilder.advanceLexer();
+      if (matchToken(PyTokenTypes.DOT) && matchToken(PyTokenTypes.DOT)) {
+        maybeEllipsis.done(PyElementTypes.NONE_LITERAL_EXPRESSION);
+        return true;
+      }
+      maybeEllipsis.rollbackTo();
+    }
+    return false;
+  }
+
   private static TokenSet BRACKET_OR_COMMA = TokenSet.create(PyTokenTypes.RBRACKET, PyTokenTypes.COMMA);
   private static TokenSet BRACKET_COLON_COMMA = TokenSet.create(PyTokenTypes.RBRACKET, PyTokenTypes.COLON, PyTokenTypes.COMMA);
 
@@ -420,7 +426,9 @@ public class ExpressionParsing extends Parsing {
     while (atToken(PyTokenTypes.COMMA)) {
       nextToken();
       PsiBuilder.Marker sliceItemStart = myBuilder.mark();
-      parseTestExpression(false, false);
+      if (!parseEllipsis()) {
+        parseTestExpression(false, false);
+      }
       if (matchToken(PyTokenTypes.COLON)) {
         inSlice = true;
         parseTestExpression(false, false);
diff --git a/python/testData/psi/EllipsisAsStatement.py b/python/testData/psi/EllipsisAsStatement.py
new file mode 100644
index 000000000000..e1efdfe13f1e
--- /dev/null
+++ b/python/testData/psi/EllipsisAsStatement.py
@@ -0,0 +1,5 @@
+def a():
+  ...     # <- highlighted as "Statement seems to have no effect"
+  pass
+
+a()
\ No newline at end of file
diff --git a/python/testData/psi/EllipsisAsStatement.txt b/python/testData/psi/EllipsisAsStatement.txt
new file mode 100644
index 000000000000..dbe4c271bd31
--- /dev/null
+++ b/python/testData/psi/EllipsisAsStatement.txt
@@ -0,0 +1,33 @@
+PyFile:EllipsisAsStatement.py
+  PyFunction('a')
+    PsiElement(Py:DEF_KEYWORD)('def')
+    PsiWhiteSpace(' ')
+    PsiElement(Py:IDENTIFIER)('a')
+    PyParameterList
+      PsiElement(Py:LPAR)('(')
+      PsiElement(Py:RPAR)(')')
+    PsiElement(Py:COLON)(':')
+    PsiWhiteSpace('\n  ')
+    PyStatementList
+      PsiElement(Py:DOT)('.')
+      PsiErrorElement:Statement expected, found Py:DOT
+        <empty list>
+      PsiElement(Py:DOT)('.')
+      PsiErrorElement:Statement expected, found Py:DOT
+        <empty list>
+      PsiElement(Py:DOT)('.')
+      PsiErrorElement:Statement expected, found Py:DOT
+        <empty list>
+      PsiWhiteSpace('     ')
+      PsiComment(Py:END_OF_LINE_COMMENT)('# <- highlighted as "Statement seems to have no effect"')
+      PsiWhiteSpace('\n  ')
+      PyPassStatement
+        PsiElement(Py:PASS_KEYWORD)('pass')
+  PsiWhiteSpace('\n\n')
+  PyExpressionStatement
+    PyCallExpression: a
+      PyReferenceExpression: a
+        PsiElement(Py:IDENTIFIER)('a')
+      PyArgumentList
+        PsiElement(Py:LPAR)('(')
+        PsiElement(Py:RPAR)(')')
\ No newline at end of file
diff --git a/python/testSrc/com/jetbrains/python/PythonParsingTest.java b/python/testSrc/com/jetbrains/python/PythonParsingTest.java
index 17513fd7c48f..283ea51cc1e4 100644
--- a/python/testSrc/com/jetbrains/python/PythonParsingTest.java
+++ b/python/testSrc/com/jetbrains/python/PythonParsingTest.java
@@ -356,6 +356,10 @@ public class PythonParsingTest extends ParsingTestCase {
     doTest();
   }
 
+  public void testEllipsisAsStatement() {  // PY-7763
+    doTest();
+  }
+
   public void doTest(LanguageLevel languageLevel) {
     LanguageLevel prev = myLanguageLevel;
     myLanguageLevel = languageLevel;