From 1d3a7823d3b6b8afdfb956f7616d6c6825c80a66 Mon Sep 17 00:00:00 2001
From: Andrey Vlasovskikh <andrey.vlasovskikh@gmail.com>
Date: Mon, 3 Sep 2012 19:39:05 +0400
Subject: [PATCH] Fixed parsing error in StatementParsing.parseSimpleStatement
 (EA-30244)

---
 .../python/parsing/StatementParsing.java      | 16 +++++++++-------
 python/testData/psi/EqYieldEq.py              |  1 +
 python/testData/psi/EqYieldEq.txt             | 19 +++++++++++++++++++
 .../jetbrains/python/PythonParsingTest.java   |  5 +++++
 4 files changed, 34 insertions(+), 7 deletions(-)
 create mode 100644 python/testData/psi/EqYieldEq.py
 create mode 100644 python/testData/psi/EqYieldEq.txt

diff --git a/python/src/com/jetbrains/python/parsing/StatementParsing.java b/python/src/com/jetbrains/python/parsing/StatementParsing.java
index ae8d235d62b1..96c7d4cb5e88 100644
--- a/python/src/com/jetbrains/python/parsing/StatementParsing.java
+++ b/python/src/com/jetbrains/python/parsing/StatementParsing.java
@@ -197,19 +197,21 @@ public class StatementParsing extends Parsing implements ITokenTypeRemapper {
 
         while (true) {
           PsiBuilder.Marker maybeExprMarker = builder.mark();
+          final boolean isYieldExpr = builder.getTokenType() == PyTokenTypes.YIELD_KEYWORD;
           if (!getExpressionParser().parseYieldOrTupleExpression(false)) {
             maybeExprMarker.drop();
             builder.error(EXPRESSION_EXPECTED);
             break;
           }
           if (builder.getTokenType() == PyTokenTypes.EQ) {
-            maybeExprMarker.rollbackTo();
-            final int rollbackOffset = builder.getCurrentOffset();
-            getExpressionParser().parseExpression(false, true);
-            final int offsetAfterExpr = builder.getCurrentOffset();
-            if (builder.getTokenType() != PyTokenTypes.EQ) {
-              LOG.error("'=' after rollback expected", builder.getTokenType() + "; " +
-                                                       builder.getOriginalText().subSequence(rollbackOffset, offsetAfterExpr).toString());
+            if (isYieldExpr) {
+              maybeExprMarker.drop();
+              builder.error("Cannot assign to 'yield' expression");
+            }
+            else {
+              maybeExprMarker.rollbackTo();
+              getExpressionParser().parseExpression(false, true);
+              LOG.assertTrue(builder.getTokenType() == PyTokenTypes.EQ, builder.getTokenType());
             }
             builder.advanceLexer();
           }
diff --git a/python/testData/psi/EqYieldEq.py b/python/testData/psi/EqYieldEq.py
new file mode 100644
index 000000000000..96f4b800df70
--- /dev/null
+++ b/python/testData/psi/EqYieldEq.py
@@ -0,0 +1 @@
+bb = yield dd = cc
diff --git a/python/testData/psi/EqYieldEq.txt b/python/testData/psi/EqYieldEq.txt
new file mode 100644
index 000000000000..a8a58a688eb5
--- /dev/null
+++ b/python/testData/psi/EqYieldEq.txt
@@ -0,0 +1,19 @@
+PyFile:EqYieldEq.py
+  PyAssignmentStatement
+    PyTargetExpression: bb
+      PsiElement(Py:IDENTIFIER)('bb')
+    PsiWhiteSpace(' ')
+    PsiElement(Py:EQ)('=')
+    PsiWhiteSpace(' ')
+    PyYieldExpression
+      PsiElement(Py:YIELD_KEYWORD)('yield')
+      PsiWhiteSpace(' ')
+      PyReferenceExpression: dd
+        PsiElement(Py:IDENTIFIER)('dd')
+    PsiErrorElement:Cannot assign to 'yield' expression
+      <empty list>
+    PsiWhiteSpace(' ')
+    PsiElement(Py:EQ)('=')
+    PsiWhiteSpace(' ')
+    PyReferenceExpression: cc
+      PsiElement(Py:IDENTIFIER)('cc')
\ 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 cf3edd5f3324..b4485a5e57c9 100644
--- a/python/testSrc/com/jetbrains/python/PythonParsingTest.java
+++ b/python/testSrc/com/jetbrains/python/PythonParsingTest.java
@@ -343,6 +343,11 @@ public class PythonParsingTest extends ParsingTestCase {
     doTest();
   }
 
+  // EA-30244
+  public void testEqYieldEq() {
+    doTest();
+  }
+
   public void doTest() {
     doTest(LanguageLevel.PYTHON25);
   }