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

2 files changed, 7 insertions, 9 deletions

diff --git a/test/CXX/basic/basic.link/p9.cpp b/test/CXX/basic/basic.link/p9.cpp
index bd16b02d7b..c895253c68 100644
--- a/test/CXX/basic/basic.link/p9.cpp
+++ b/test/CXX/basic/basic.link/p9.cpp
@@ -6,6 +6,5 @@ namespace N { } // expected-note{{here}}
 // First bullet: two names with external linkage that refer to
 // different kinds of entities.
 void f() {
-  int N(); // expected-error{{redefinition}}
+  int N(); // expected-error{{redefinition}} expected-warning{{interpreted as a function declaration}}
 }
-
diff --git a/test/CXX/dcl.dcl/basic.namespace/namespace.udecl/p11.cpp b/test/CXX/dcl.dcl/basic.namespace/namespace.udecl/p11.cpp
index 63b302265e..b1dcf4d015 100644
--- a/test/CXX/dcl.dcl/basic.namespace/namespace.udecl/p11.cpp
+++ b/test/CXX/dcl.dcl/basic.namespace/namespace.udecl/p11.cpp
@@ -25,13 +25,13 @@ namespace test1 {
 namespace test2 {
   namespace ns { void foo(); } // expected-note 2 {{target of using declaration}}
   void test0() {
-    int foo(); // expected-note {{conflicting declaration}}
+    int foo(); // expected-note {{conflicting declaration}} expected-warning{{function declaration}}
     using ns::foo; // expected-error {{target of using declaration conflicts with declaration already in scope}}
   }
 
   void test1() {
     using ns::foo; //expected-note {{using declaration}}
-    int foo(); // expected-error {{declaration conflicts with target of using declaration already in scope}}
+    int foo(); // expected-error {{declaration conflicts with target of using declaration already in scope}} expected-warning{{function declaration}}
   }
 }
 
@@ -39,7 +39,7 @@ namespace test3 {
   namespace ns { void foo(); } // expected-note 2 {{target of using declaration}}
   class Test0 {
     void test() {
-      int foo(); // expected-note {{conflicting declaration}}
+      int foo(); // expected-note {{conflicting declaration}} expected-warning{{function declaration}}
       using ns::foo; // expected-error {{target of using declaration conflicts with declaration already in scope}}
     }
   };
@@ -47,7 +47,7 @@ namespace test3 {
   class Test1 {
     void test() {
       using ns::foo; //expected-note {{using declaration}}
-      int foo(); // expected-error {{declaration conflicts with target of using declaration already in scope}}
+      int foo(); // expected-error {{declaration conflicts with target of using declaration already in scope}} expected-warning{{function declaration}}
     }
   };
 }
@@ -56,7 +56,7 @@ namespace test4 {
   namespace ns { void foo(); } // expected-note 2 {{target of using declaration}}
   template <typename> class Test0 {
     void test() {
-      int foo(); // expected-note {{conflicting declaration}}
+      int foo(); // expected-note {{conflicting declaration}} expected-warning{{function declaration}}
       using ns::foo; // expected-error {{target of using declaration conflicts with declaration already in scope}}
     }
   };
@@ -64,7 +64,7 @@ namespace test4 {
   template <typename> class Test1 {
     void test() {
       using ns::foo; //expected-note {{using declaration}}
-      int foo(); // expected-error {{declaration conflicts with target of using declaration already in scope}}
+      int foo(); // expected-error {{declaration conflicts with target of using declaration already in scope}} expected-warning{{function declaration}}
     }
   };
 }
@@ -91,4 +91,3 @@ namespace test5 {
   template class Test0<int>;
   template class Test1<int>; // expected-note {{in instantiation of member function}}
 }
-