Index: lib/Serialization/ASTReaderStmt.cpp
===================================================================
--- lib/Serialization/ASTReaderStmt.cpp
+++ lib/Serialization/ASTReaderStmt.cpp
@@ -1575,6 +1575,7 @@
   E->Loc = Range.getBegin();
   E->RParen = Range.getEnd();
   E->QueriedType = GetTypeSourceInfo(Record, Idx);
+  E->Dimension = Reader.ReadSubExpr();
 }
 
 void ASTStmtReader::VisitExpressionTraitExpr(ExpressionTraitExpr *E) {
Index: lib/Serialization/ASTWriterStmt.cpp
===================================================================
--- lib/Serialization/ASTWriterStmt.cpp
+++ lib/Serialization/ASTWriterStmt.cpp
@@ -1576,6 +1576,7 @@
   Record.push_back(E->getValue());
   Record.AddSourceRange(E->getSourceRange());
   Record.AddTypeSourceInfo(E->getQueriedTypeSourceInfo());
+  Record.AddStmt(E->getDimensionExpression());
   Code = serialization::EXPR_ARRAY_TYPE_TRAIT;
 }