From: Richard Smith <richard-llvm@metafoo.co.uk>
Date: Tue, 20 Dec 2011 22:56:20 +0000 (+0000)
Subject: PR11297: Provide a better diagnostic for code which contains a
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=a44854a23b3f090729d82f447aa88df4f6563263;p=clang

PR11297: Provide a better diagnostic for code which contains a
reasonable-looking but ill-formed for-range statement of the form:

  for (expression : expression)


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@147006 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/include/clang/Basic/DiagnosticParseKinds.td b/include/clang/Basic/DiagnosticParseKinds.td
index 0f5fb58ac7..74c4418ce6 100644
--- a/include/clang/Basic/DiagnosticParseKinds.td
+++ b/include/clang/Basic/DiagnosticParseKinds.td
@@ -244,6 +244,8 @@ def ext_for_range : ExtWarn<
 def warn_cxx98_compat_for_range : Warning<
   "range-based for loop is incompatible with C++98">,
   InGroup<CXX98Compat>, DefaultIgnore;
+def err_for_range_expected_decl : Error<
+  "for range declaration must declare a variable">;
 def err_argument_required_after_attribute : Error<
   "argument required after attribute">;
 def err_missing_param : Error<"expected parameter declarator">;
diff --git a/lib/Parse/ParseStmt.cpp b/lib/Parse/ParseStmt.cpp
index 435bde3375..13b3bdaf74 100644
--- a/lib/Parse/ParseStmt.cpp
+++ b/lib/Parse/ParseStmt.cpp
@@ -1371,6 +1371,14 @@ StmtResult Parser::ParseForStatement(ParsedAttributes &attrs) {
         return StmtError();
       }
       Collection = ParseExpression();
+    } else if (getLang().CPlusPlus0x && Tok.is(tok::colon) &&
+               !FirstPart.isInvalid()) {
+      // User tried to write the reasonable, but ill-formed, for-range-statement
+      //   for (expr : expr) { ... }
+      Diag(Tok, diag::err_for_range_expected_decl)
+        << FirstPart.get()->getSourceRange();
+      SkipUntil(tok::r_paren, false, true);
+      SecondPartIsInvalid = true;
     } else {
       if (!Value.isInvalid()) {
         Diag(Tok, diag::err_expected_semi_for);
diff --git a/test/Parser/cxx0x-for-range.cpp b/test/Parser/cxx0x-for-range.cpp
new file mode 100644
index 0000000000..f920ef9085
--- /dev/null
+++ b/test/Parser/cxx0x-for-range.cpp
@@ -0,0 +1,30 @@
+// RUN: %clang_cc1 -fsyntax-only -verify -std=c++11 %s
+
+template<typename T, typename U>
+struct pair {};
+
+template<typename T, typename U>
+struct map {
+  typedef pair<T,U> *iterator;
+  iterator begin();
+  iterator end();
+};
+
+template<typename T, typename U>
+pair<T,U> &tie(T &, U &);
+
+int foo(map<char*,int> &m) {
+  char *p;
+  int n;
+
+  for (pair<char*,int> x : m) {
+    (void)x;
+  }
+
+  for (tie(p, n) : m) { // expected-error {{for range declaration must declare a variable}}
+    (void)p;
+    (void)n;
+  }
+
+  return n;
+}