[llvm-bugs] [Bug 25120] New: Warn on pointless casts with fixit to remove them

[via llvm-bugs]

https://llvm.org/bugs/show_bug.cgi?id=25120

            Bug ID: 25120
           Summary: Warn on pointless casts with fixit to remove them
           Product: clang
           Version: 3.5
          Hardware: PC
                OS: Linux
            Status: NEW
          Severity: enhancement
          Priority: P
         Component: Frontend
          Assignee: unassignedclangbugs at nondot.org
          Reporter: bugzilla at tecnocode.co.uk
                CC: llvm-bugs at lists.llvm.org
    Classification: Unclassified

It would be nice if Clang warned about pointless casts:
 • casting a value of type (X*) to (X*)
 • casting a value of type (X*) to a qualified version of (X*), like (const X*)
because these casts are entirely pointless as per §6.5.4¶5 of
http://www.open-std.org/jtc1/sc22/wg14/www/docs/n1570.pdf, plus footnote 104.

test.c:
   void some_func (const char *const_param) {}

   int
   main (void)
   {
     char *str = "hi";

     some_func (str);  /* fine */
     some_func ((const char *) str);  /* should warn */
     some_func ((char *) str);  /* should warn */
   }

$ clang -Weverything -Wno-missing-prototypes -Wno-unused-parameter test.c
$ clang --version
clang version 3.5.0 (tags/RELEASE_350/final)
Target: x86_64-redhat-linux-gnu
Thread model: posix

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