PR10828: Produce a warning when a no-arguments function is declared in block
scope, when no other indication is provided that the user intended to declare a
function rather than a variable.

Remove some false positives from the existing 'parentheses disambiguated as a
function' warning by suppressing it when the declaration is marked as 'typedef'
or 'extern'.

Add a new warning group -Wvexing-parse containing both of these warnings.

The new warning is enabled by default; despite a number of false positives (and
one bug) in clang's test-suite, I have only found genuine bugs with it when
running it over a significant quantity of real C++ code.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@147599 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/test/SemaCXX/conditional-expr.cpp b/test/SemaCXX/conditional-expr.cpp
index 5648d02..3cfddb3 100644
--- a/test/SemaCXX/conditional-expr.cpp
+++ b/test/SemaCXX/conditional-expr.cpp
@@ -96,8 +96,8 @@
   (void)(i1 ? BadDerived() : BadBase());
 
   // b2.1 (hierarchy stuff)
-  const Base constret();
-  const Derived constder();
+  const Base constret(); // expected-warning {{interpreted as a function declaration}}
+  const Derived constder(); // expected-warning {{interpreted as a function declaration}}
   // should use const overload
   A a1((i1 ? constret() : Base()).trick());
   A a2((i1 ? Base() : constret()).trick());
diff --git a/test/SemaCXX/decl-expr-ambiguity.cpp b/test/SemaCXX/decl-expr-ambiguity.cpp
index 1ddff80..555e89c 100644
--- a/test/SemaCXX/decl-expr-ambiguity.cpp
+++ b/test/SemaCXX/decl-expr-ambiguity.cpp
@@ -1,4 +1,4 @@
-// RUN: %clang_cc1 -fsyntax-only -verify -pedantic-errors %s 
+// RUN: %clang_cc1 -fsyntax-only -verify -pedantic-errors %s
 
 void f() {
   int a;
@@ -24,10 +24,15 @@
   // Declarations.
   int fd(T(a)); // expected-warning {{parentheses were disambiguated as a function declarator}}
   T(*d)(int(p)); // expected-warning {{parentheses were disambiguated as a function declarator}} expected-note {{previous definition is here}}
+  typedef T(*td)(int(p));
+  extern T(*tp)(int(p));
+  T d3(); // expected-warning {{empty parentheses interpreted as a function declaration}}
+  typedef T d3t();
+  extern T f3();
   T(d)[5]; // expected-error {{redefinition of 'd'}}
   typeof(int[])(f) = { 1, 2 }; // expected-error {{extension used}}
   void(b)(int);
-  int(d2) __attribute__(()); 
+  int(d2) __attribute__(());
   if (int(a)=1) {}
   int(d3(int()));
 }