Don't assume that a valid expression for the first part of a for-statement

is non-null when diagnosing a broken attempt to write a for-range-statement.

llvm-svn: 151081

clang/lib/Parse/ParseStmt.cpp

@@ -1396,8 +1396,7 @@ StmtResult Parser::ParseForStatement(ParsedAttributes &attrs,
         return StmtError();
       }
       Collection = ParseExpression();
-    } else if (getLang().CPlusPlus0x && Tok.is(tok::colon) &&
-               !FirstPart.isInvalid()) {
+    } else if (getLang().CPlusPlus0x && Tok.is(tok::colon) && FirstPart.get()) {
       // User tried to write the reasonable, but ill-formed, for-range-statement
       //   for (expr : expr) { ... }
       Diag(Tok, diag::err_for_range_expected_decl)

clang/test/SemaCXX/for-range-examples.cpp

@@ -169,3 +169,14 @@ namespace test3 {
   template<typename T> void f() { for (auto a : A()) {} }
   void g() { f<int>(); }
 }
+
+namespace test4 {
+  void f() {
+    int y;
+
+    // Make sure these don't crash. Better diagnostics would be nice.
+    for (: {1, 2, 3}) {} // expected-error {{expected expression}} expected-error {{expected ';'}}
+    for (x : {1, 2, 3}) {} // expected-error {{undeclared identifier}} expected-error {{expected ';'}}
+    for (y : {1, 2, 3}) {} // expected-error {{must declare a variable}} expected-warning {{result unused}}
+  }
+}