Add the initial TypoExpr AST node for delayed typo correction.

llvm-svn: 220692
diff --git a/clang/lib/Serialization/ASTReaderStmt.cpp b/clang/lib/Serialization/ASTReaderStmt.cpp
index d2b7568..5b4e12c 100644
--- a/clang/lib/Serialization/ASTReaderStmt.cpp
+++ b/clang/lib/Serialization/ASTReaderStmt.cpp
@@ -1588,6 +1588,10 @@
   E->Loc = ReadSourceLocation(Record, Idx);
 }
 
+void ASTStmtReader::VisitTypoExpr(TypoExpr *E) {
+  llvm_unreachable("Cannot read TypoExpr nodes");
+}
+
 //===----------------------------------------------------------------------===//
 // Microsoft Expressions and Statements
 //===----------------------------------------------------------------------===//