well.
Also, clean up the flow of the code a bit, and factor things more
nicely.
Finally, add the test case that was missing from my previous
commit (sorry), with new tests added to cover temporaries and other fun
cases.
llvm-svn: 139077
of the function in question when applicable (that is, not for blocks).
Patch by Joerg Sonnenberger with some stylistic tweaks by me.
When discussing this weth Joerg, streaming the decl directly into the
diagnostic didn't work because we have a pointer-to-const, and the
overload doesn't accept such. In order to make my style tweaks to the
patch, I first changed the overload to accept a pointer-to-const, and
then changed the diagnostic printing layer to also use
a pointer-to-const, cleaning up a gross line of code along the way.
llvm-svn: 138854
collision between C99 hexfloats and C++0x user-defined literals by
giving C99 hexfloats precedence. Also, warning about user-defined
literals that conflict with hexfloats and those that have names that
are reserved by the implementation. Fixes <rdar://problem/9940194>.
llvm-svn: 138839
This makes the code duplication of implicit special member handling even worse,
but the cleanup will have to come later. For now, this works.
Follow-up with tests for explicit defaulting and enabling the __has_feature
flag to come.
llvm-svn: 138821
system flags an error when unlocking a lock which was not held, locking
the same lock twice, having a different lockset on each iteration of a
loop, or going out of scope while still holding a lock. In order to
successfully use the lockset, this patch also makes sure that attribute
arguments are attached correctly for later parsing.
This patch was also worked on by DeLesley Hutchins.
Note: This patch has been reviewed by Chandler Carruth and Jeffrey
Yasskin. Feel free to provide post-commit review comments for a
subsequent patch.
llvm-svn: 138350
For the test case added to function-redecl.cpp, we were previously complaining
about a mismatch in the parameter types, since the definition used the
typedef'd type.
llvm-svn: 138318
const int &x = x;
This crashed by inifinetly recursing within the lvalue evaluation
routine. I've added a (somewhat) braindead way of preventing this
recursion. If folks have better suggestions for how to avoid it I'm all
ears.
That said, we have some work to do. This doesn't trigger a single
warning for uninitialized, self-initialized or otherwise completely
wrong code. In some senses, the crash was almost better.
llvm-svn: 138239
even when overloaded and user-defined. These operators are both more
valuable to warn on (due to likely typos) and extremely unlikely to be
reasonable for use to trigger side-effects.
llvm-svn: 137823
-Wunused was a mistake. It resulted in duplicate warnings and lots of
other hacks. Instead, this should be a special sub-category to
-Wunused-value, much like -Wunused-result is.
Moved to -Wunused-comparison, moved the implementation to piggy back on
the -Wunused-value implementation instead of rolling its own, different
mechanism for catching all of the "interesting" statements.
I like the unused-value mechanism for this better, but its currently
missing several top-level statements. For now, I've FIXME-ed out those
test cases. I'll enhance the generic infrastructure to catch these
statements in a subsequent patch.
This patch also removes the cast-to-void fixit hint. This hint isn't
available on any of the other -Wunused-value diagnostics, and if we want
it to be, we should add it generically rather than in one specific case.
llvm-svn: 137822
code is very likely to be buggy, but its going to require more
significant changes on the part of the user to correct it in this case.
llvm-svn: 137820
a complement to the warnings we provide in condition expressions. Much
like we warn on conditions such as:
int x, y;
...
if (x = y) ... // Almost always a typo of '=='
This warning applies the complementary logic to "top-level" statements,
or statements whose value is not consumed or used in some way:
int x, y;
...
x == y; // Almost always a type for '='
We also mirror the '!=' vs. '|=' logic.
The warning is designed to fire even for overloaded operators for two reasons:
1) Especially in the presence of widespread templates that assume
operator== and operator!= perform the expected comparison operations,
it seems unreasonable to suppress warnings on the offchance that
a user has written a class that abuses these operators, embedding
side-effects or other magic within them.
2) There is a trivial source modification to silence the warning for
truly exceptional cases:
(void)(x == y); // No warning
A (greatly reduced) form of this warning has already caught a number of
bugs in our codebase, so there is precedent for it actually firing. That
said, its currently off by default, but enabled under -Wall.
There are several fixmes left here that I'm working on in follow-up
patches, including de-duplicating warnings from -Wunused, sharing code
with -Wunused's implementation (and creating a nice place to hook
diagnostics on "top-level" statements), and handling cases where a proxy
object with a bool conversion is returned, hiding the operation in the
cleanup AST nodes.
Suggestions for any of this code more than welcome. Also, I'd really
love suggestions for better naming than "top-level".
llvm-svn: 137819
Old warning:
warning: use of NULL in arithmetic operation [-Wnull-arithmetic]
return 10 <= NULL;
^ ~~~~
New warning:
warning: comparison between NULL and non-pointer ('int' and NULL) [-Wnull-arithmetic]
return 10 <= NULL;
~~ ^ ~~~~
llvm-svn: 137377
This patch special cases the parser for thread safety attributes so that all
attribute arguments are put in the argument list (instead of a special
parameter) since arguments may not otherwise resolve correctly without two-token
lookahead.
This patch also adds checks to make sure that attribute arguments are
lockable objects.
llvm-svn: 137130
case situations with the unary operators & and *. Also extend the array bounds
checking to work with pointer arithmetic; the pointer arithemtic checking can
be turned on using -Warray-bounds-pointer-arithmetic.
The changes to where CheckArrayAccess gets called is based on some trial &
error and a bunch of digging through source code and gdb backtraces in order
to have the check performed under as many situations as possible (such as for
variable initializers, arguments to function calls, and within conditional in
addition to the simpler cases of the operands to binary and unary operator)
while not being called--and triggering warnings--more than once for a given
ArraySubscriptExpr.
llvm-svn: 136997
arrays. This now suppresses the warning only in the case of
a one-element array as the last field in a struct where the array size
is a literal '1' rather than any macro expansion or template parameter.
This doesn't distinguish between the language standard in use to allow
code which dates from C89 era to compile without the warning even in C99
and C++ builds. We could add a separate warning (under a different flag)
with fixit hints to switch to a flexible array, but its not clear that
this would be desirable. Much of the code using this idiom is striving
for maximum portability.
Tests were also fleshed out a bit, and the diagnostic itself tweaked to
be more pretty w.r.t. single elment arrays. This is more ugly than
I would like due to APInt's not being supported by the diagnostic
rendering engine.
A pseudo-patch for this was proposed by Nicola Gigante, but I reworked
it both for several correctness issues and for code style.
Sorry this was so long in coming.
llvm-svn: 136965
when performing typo correction involving any overloaded template functions.
The added test cases, while currently demontrating sub-optimal behavior, will
not trigger any messages without the 1-line change to SemaExpr.cpp.
llvm-svn: 136943
Having a function declaration and definition with different types for a
parameter where the types have same (textual) name can occur when an unqualified
type name resolves to types in different namespaces in each location.
The error messages have been extended by adding notes that point to the first
parameter of the function definition that doesn't match the declaration, instead
of a generic "member declaration nearly matches". The generic message is still
used in cases where the mismatch is not in the paramenter list, such as
mismatched cv qualifiers on the member function itself.
llvm-svn: 136891
Change TypoCorrection to store a set of NamedDecls instead of a single
NamedDecl. Also add initial support for performing function overload
resolution to Sema::DiagnoseEmptyLookup.
llvm-svn: 136807
has a single element. This disables the warning in cases where
there is a clear bug, but this is really rare (who uses arrays
with one element?) and it also silences a large class of false
positive issues with C89 code that is using tail padding in structs.
A better version of this patch would detect when an array is in
a tail position in a struct, but at least patch fixes the huge
false positives that are hitting postgres and other code.
llvm-svn: 136724
1. Attempting to delete an expression of incomplete class type should be an error, not a warning.
2. If someone tries to delete a pointer to an incomplete class type, make sure we actually emit
the delete expression after we warn.
llvm-svn: 136161
and to work with pointer arithmetic in addition to array indexing.
The new pointer arithmetic porition of the array bounds checking can be
turned on by -Warray-bounds-pointer-arithmetic (and is off by default).
llvm-svn: 136046
considering explicit conversion operators when determining surrogate
functions. Fixes PR10453. Note that there are a few test cases where
Clang is still wrong because it does not implement DR899; see PR10456.
Patch by Jonathan Sauer!
llvm-svn: 135857
This is accomplished by forcing the needed expressions for -Wuninitialized to always be CFGElements in the CFG.
This allows us to remove a fair amount of the code for -Wuninitialized.
Some fallout:
- AnalysisBasedWarnings.cpp now specifically toggles the CFGBuilder to create a CFG that is suitable for -Wuninitialized. This
is a layering violation, since the logic for -Wuninitialized is in libAnalysis. This can be fixed with the proper refactoring.
- Some of the source locations for -Wunreachable-code warnings have shifted. While not ideal, this is okay because that analysis
already needs some serious reworking.
llvm-svn: 135480
template<unsigned int A, unsigned int B> struct S {
int foo() {
int x = A && B;
}
}
will not warn on A && B on every instantiation. This will still warn on other cases inside templates, which will be caught on checking the template definition.
llvm-svn: 135222
Revert "For C++11, do more checking of initializer lists up-front, enabling some subset of the final functionality. C just leaves the function early. C++98 runs through the same code path, but has no changed functionality either."
This reverts commit ac420c5053d6aa41d59f782caad9e46e5baaf2c2.
llvm-svn: 135210
template<typename T> struct S { } f() { return 0; }
This case now produces a missing ';' diagnostic, since that seems like a much more likely error than an attempt to declare a function or variable in addition to the class template.
Treat this
llvm-svn: 135195
This is a first baby step towards supporting generalized initializer lists. This also removes an aggregate
test case that was just plain wrong, assuming that non-aggregates couldn't be initialized with initializer lists
in C++11 mode.
llvm-svn: 135177
int f(int x) {
if (int foo = f(bar)) {}
return 0;
}
Clang produces the following error messages:
paren_imbalance.cc:2:19: error: use of undeclared identifier 'bar'
if (int foo = f(bar)) {}
^
paren_imbalance.cc:2:26: error: expected ')'
if (int foo = f(bar)) {}
^
paren_imbalance.cc:2:6: note: to match this '('
if (int foo = f(bar)) {}
^
The second error is incorrect. This patch will stop Clang from producing an error on parenthesis imbalance during error recovery when there isn't one.
llvm-svn: 134258
vector<int>
to
std::vector<int>
Patch by Kaelyn Uhrain, with minor tweaks + PCH support from me. Fixes
PR5776/<rdar://problem/8652971>.
Thanks Kaelyn!
llvm-svn: 134007
of a single if block. This is really annoying to track down and test.
Silly changes to the test case caused it to stop showing up. I wish
there were a more concrete way of asserting that a note attaches to the
intended diagnostic.
This fixes PR10195.
llvm-svn: 133907
arithmetic into a couple of common routines. Use these to make the
messages more consistent in the various contexts, especially in terms of
consistently diagnosing binary operators with invalid types on both the
left- and right-hand side. Also, improve the grammar and wording of the
messages some, handling both two pointers and two (different) types.
The wording of function pointer arithmetic diagnostics still strikes me
as poorly phrased, and I worry this makes them slightly more awkward if
more consistent. I'm hoping to fix that with a follow-on patch and test
case that will also make them more helpful when a typedef or template
type parameter makes the type completely opaque.
Suggestions on better wording are very welcome, thanks to Richard Smith
for some initial help on that front.
llvm-svn: 133906
When performing semantic analysis on a member declaration, fix the check for whether we are declaring a function to check for parenthesized declarators, declaration via decltype, etc.
Also fix the semantic check to not treat FuncType* as a function type.
llvm-svn: 133862
declaration, determine whether the declaration will end up declaring a
function using semantic criteria (e.g., it will have function type)
rather than purely syntactic criteria (e.g., it has the form of a
function declarator). Fixes <rdar://problem/9670557>.
llvm-svn: 133854
conventions. I then discovered a typo in the using declaration bit in
LookupSpecialMember. This led to discovering [namespace.udecl]p15, which
clang implements incorrectly. Thus I've added a comment and implemented
the code consistently with the rest of clang - that is incorrectly.
And because I don't want to include tests of something incorrect, I've
ripped the test out.
llvm-svn: 133784
types printed in various diagnostics.
We could omit checking for the types, but that can mask errors where the
wrong type is streamed into the diagnostic. There was at least one of
these caught by this test already.
llvm-svn: 133429
pointers I found while working on the NULL arithmetic warning. We here
always assuming the LHS was the pointer, instead of using the selected
pointer expression.
llvm-svn: 133428
effectively that this abstraction simply doesn't exist. That is
highlighted by the fact that by using it we were papering over a more
serious error in this warning: the fact that we warned for *invalid*
constructs involving member pointers and block pointers.
I've fixed the obvious issues with the warning here, but this is
confirming an original suspicion that this warning's implementation is
flawed. I'm looking into how we can implement this more reasonably. WIP
on that front.
llvm-svn: 133425
Trieu, and fix them by checking for array and function types as well as
pointer types.
I've added a predicate method on Type to bundle together the logic we're
using here: isPointerLikeType(). I'd welcome better names for this
predicate, this is the best I came up with. It's implemented as a switch
to be a touch lighter weight than all the chained isa<...> casts that
would result otherwise.
llvm-svn: 133383
__builtin_ versions of these functions as well as the normal function
versions, so that it works on platforms where memset/memcpy/memmove
are macros that map down to the builtins (e.g., Darwin). Fixes
<rdar://problem/9372688>.
llvm-svn: 133173
and the programmer intended to write 'sizeof(*p)'. There are several
elements to the new version:
1) The actual expressions are compared in order to more accurately flag
the case where the pattern that works for an array has been used, or
a '*' has been omitted.
2) Only do a loose type-based check for record types. This prevents us
from warning when we happen to be copying around chunks of data the
size of a pointer and the pointer types for the sizeof and
source/dest match.
3) Move all the diagnostics behind the runtime diagnostic filter. Not
sure this is really important for this particular diagnostic, but
almost everything else in SemaChecking.cpp does so.
4) Make the wording of the diagnostic more precise and informative. At
least to my eyes.
5) Provide highlighting for the two expressions which had the unexpected
similarity.
6) Place this diagnostic under a flag: -Wsizeof-pointer-memaccess
This uses the Stmt::Profile system for computing #1. Because of the
potential cost, this is guarded by the warning flag. I'd be interested
in feedback on how bad this is in practice; I would expect it to be
quite cheap in practice. Ideas for a cheaper / better way to do this are
also welcome.
The diagnostic wording could likely use some further wordsmithing.
Suggestions welcome here. The goals I had were to: clarify that its the
interaction of 'memset' and 'sizeof' and give more reasonable
suggestions for a resolution.
An open question is whether these diagnostics should have the note
attached for silencing by casting the dest/source pointer to void*.
llvm-svn: 133155
argument types for mem{set,cpy,move}. Character pointers, much like void
pointers, often point to generic "memory", so trying to check whether
they match the type of the argument to 'sizeof' (or other checks) is
unproductive and often results in false positives.
Nico, please review; does this miss any of the bugs you were trying to
find with this warning? The array test case you had should be caught by
the array-specific sizeof warning I think.
llvm-svn: 133136
as constant size arrays. This has slightly different semantics in some insane cases, but allows
us to accept some constructs that GCC does. Continue to be pedantic in -std=c99 and other
modes. This addressed rdar://8733881 - error "variable-sized object may not be initialized"; g++ accepts same code
llvm-svn: 132983
- Move a test from test/SemaTemplate/instantiate-expr-3.cpp, it did not belong there
- Incomplete and abstract types are considered hard errors
llvm-svn: 132979
struct {
typedef int A = 0;
};
According to the C++11 standard, this is not ill-formed, but does not have any ascribed meaning. We can't reasonably accept it, so treat it as ill-formed.
Also switch C++ from an incorrect 'fields can only be initialized in constructors' diagnostic for this case to C's 'illegal initializer (only variables can be initialized)'
llvm-svn: 132890
- Removed fix-it hints from template instaniations since changes to the
templates are rarely helpful.
- Changed the caret in template instaniations from the class/struct name to the
class/struct keyword, matching the other warnings.
- Do not offer fix-it hints when multiple declarations disagree. Warnings are
still given.
- Once a definition is found, offer a fix-it hint to all previous declarations
with wrong tag.
- Declarations that disagree with a previous definition will get a fix-it hint
to change the declaration.
llvm-svn: 132831
compared even when one is a reference binding and the other is not
(<rdar://problem/9173984>), but the definition of an identity sequence
does not involve lvalue-to-rvalue adjustments (PR9507). Fix both
inter-related issues.
llvm-svn: 132660
In code such as "char* volatile const j()", Clang warns that "volatile
const" will be ignored. Make it point to the first ignored qualifier,
and simplify the code a bit.
llvm-svn: 132563
diagnostic group to cover the cases where we have definitively bad
behavior: dynamic classes.
It also rips out the existing support for POD-based checking. This
didn't work well, and triggered too many false positives. I'm looking
into a possibly more principled way to warn on the fundamental buggy
construct here. POD-ness isn't the critical aspect anyways, so a clean
slate is better. This also removes some silliness from the code until
the new checks arrive.
llvm-svn: 132534
makes it into a special member function. This is very bad and can lead
to all sorts of nastiness including implicit member functions violating
the One Definition Rule. This should probably be made ill-formed in a
later version of the standard, but for now we'll just warn.
llvm-svn: 132104
type that turns one type into another. This is used as the basis to
implement __underlying_type properly - with TypeSourceInfo and proper
behavior in the face of templates.
llvm-svn: 132017
through sugared types when testing for TagTypes. This was the actual
cause of the only false positive in Clang+LLVM.
Next evaluation will be over a much larger selection of code including
large amounts of open source code.
llvm-svn: 131957
Example:
class A { public: int f(); };
class B : public A { private: using A::f; };
class C : public B { private: using B::f; };
Here, B::f is private so this should fail in Standard C++, but because B::f refers to A::f which is public MSVC accepts it.
This fixes 1 error when parsing MFC code with clang.
llvm-svn: 131896
minor issues along the way:
- Non-type template parameters of type 'std::nullptr_t' were not
permitted.
- We didn't properly introduce built-in operators for nullptr ==,
!=, <, <=, >=, or > as candidate functions .
To my knowledge, there's only one (minor but annoying) part of nullptr
that hasn't been implemented: catching a thrown 'nullptr' as a pointer
or pointer-to-member, per C++0x [except.handle]p4.
llvm-svn: 131813
non-POD/non-trivial object throuugh a C-style varargs. The warning
itself was default-mapped to error, but can be downgraded, but we were
treating it in Sema like a hard error, silently dropping the call.
Instead, treat this problem like a warning, and do what the warning
says we do: abort at runtime. To do so, we fake up a __builtin_trap()
expression that gets evaluated as part of the argument.
llvm-svn: 131805
member functions by making sure that they're on the record before
checking for deletion.
Also make sure source locations are valid to avoid crashes.
Unfortunately, the declare-all-implicit-members approach is still
required in order to ensure that dependency loops do not result in
incorrectly deleting functions (since they are to be deleted at the
declaration point per the standard).
Fixes PR9917
llvm-svn: 131520
I have on that's #if 0'ed out, and I don't know why it's failing to
delete the constructor. I'd appreciate if someone familiar with access
control could look into ShouldDeleteDefaultConstructor - thanks.
llvm-svn: 131486
template<class U>
struct X1 {
template<class T> void f(T*);
template<> void f(int*) { }
};
Won't be so simple. I need to think more about it.
llvm-svn: 131362
I've edited one diagnostic which would print "copy constructor" for copy
constructors and "constructor" for any other constructor. If anyone is
extremely enamored with this, it can be reinstated with a simple boolean
flag rather than calling getSpecialMember, which is inappropriate.
llvm-svn: 131143
hasTrivialDefaultConstructor() really really means it now.
Also implement a fun standards bug regarding aggregates. Doug, if you'd
like, I can un-implement that bug if you think it is truly a defect.
The bug is that non-special-member constructors are never considered
user-provided, so the following is an aggregate:
struct foo {
foo(int);
};
It's kind of bad, but the solution isn't obvious - should
struct foo {
foo (int) = delete;
};
be an aggregate or not?
Lastly, add a missing initialization to FunctionDecl.
llvm-svn: 131101
- New isDefined() function checks for deletedness
- isThisDeclarationADefinition checks for deletedness
- New doesThisDeclarationHaveABody() does what
isThisDeclarationADefinition() used to do
- The IsDeleted bit is not propagated across redeclarations
- isDeleted() now checks the canoncial declaration
- New isDeletedAsWritten() does what it says on the tin.
- isUserProvided() now correct (thanks Richard!)
This fixes the bug that we weren't catching
void foo() = delete;
void foo() {}
as being a redefinition.
llvm-svn: 131013
sense). Fixes <rdar://problem/9366066> by eliminating an inconsistency
between C++ overloading (which handled scoped enumerations correctly)
and C binary operator type-checking (which didn't).
llvm-svn: 130924
the overloading of member and non-member functions results in arity
mismatches that don't fit well into our overload-printing scheme. This
only happens for invalid code (which breaks the arity invariants for
these cases), so just suppress the diagnostic rather than inventing
anything new. Fixes <rdar://problem/9222009>.
llvm-svn: 130902
We can use this to produce nice diagnostics (and try to fixit-and-recover) in
various cases where we might see "MyFunction" instead of "MyFunction()". The
changes in SemaExpr are an example of how to use isExprCallable.
llvm-svn: 130878
This is more efficient as it's all done at once at the end of the TU.
This could still get expensive, so a flag is provided to disable it. As
an added bonus, the diagnostics will now print out a cycle.
The PCH test is XFAILed because we currently can't deal with a note
emitted in the header and I, being tired, see no other way to verify the
serialization of delegating constructors. We should probably address
this problem /somehow/ but no good solution comes to mind.
llvm-svn: 130836
tag, filter out those ambiguous names that we found if they aren't
within the declaration context where this newly-defined tag will be
visible.
This is basically a hack, because we really need to fix the lookup of
tag declarations in this case to not find things it
shouldn't. However, it's better than what we had before, and it fixes
<rdar://problem/9168556>.
llvm-svn: 130810
the body of a delegating constructor call.
This means that the delegating constructor implementation should be
complete and correct, though there are some rough edges (diagnostic
quality with the cycle detection and using a deleted destructor).
llvm-svn: 130803
checking both the source and the destination operands, renaming the
warning group to -Wnon-pod-memaccess and tweaking the diagnostic text
in the process.
llvm-svn: 130786
As far as I know, this implementation is complete but might be missing a
few optimizations. Exceptions and virtual bases are handled correctly.
Because I'm an optimist, the web page has appropriately been updated. If
I'm wrong, feel free to downgrade its support categories.
llvm-svn: 130642
types after looking through arrays. Arrays with an unknown bound seem to
be specifically allowed in the library type traits in C++0x, and GCC's
builtin __is_trivial returns 'true' for the type 'int[]'. Now Clang
agrees with GCC about __is_trivial here.
Also hardens these methods against dependent types by just returning false.
llvm-svn: 130605
positives still further.
The plan is to:
1) Create a more targeted warning for memset of memory pointing at
a type with virtual methods or bases where a vptr would be
overwritten.
2) Consider turning the above warning back on by default.
3) Evaluate whether any false positives in the existing warning can be
detected and white listed in the warning implementation.
4) If #3 lowers the noise floor enough, enable the full warning in -Wall
or -Wextra.
Comments or suggestions welcome. Even more welcome are specific test
cases which trigger the warning and shouldn't.
llvm-svn: 130538
definition of POD. Specifically, this allows certain non-aggregate
types due to their data members being private.
The representation of C++11 POD testing is pretty gross. Any suggestions
for improvements there are welcome. Especially the name
'isCXX11PODType()' seems truly unfortunate.
llvm-svn: 130492
non-CVR qualifiers as well as CVR qualifiers. For example, don't allow
a reference to an integer in address space 1 to bind to an integer in
address space 2.
llvm-svn: 130411
as a keyword for the __is_signed type trait. Cope with this conflict
via some hackish recovery: if we see a declaration of the form
static const bool __is_signed
then we stop treating __is_signed as a keyword and instead treat it as
an identifier. It's ugly, but it's better than making the __is_signed
type trait conditional on some language flag. Fixes PR9804.
llvm-svn: 130399
Patch authored by John Wiegley.
These are array type traits used for parsing code that employs certain
features of the Embarcadero C++ compiler: __array_rank(T) and
__array_extent(T, Dim).
llvm-svn: 130351
Patch authored by John Wiegley.
These type traits are used for parsing code that employs certain features of
the Embarcadero C++ compiler. Several of these constructs are also desired by
libc++, according to its project pages (such as __is_standard_layout).
llvm-svn: 130342
a destination pointer that points to a non-POD type. This can flag such
horrible bugs as overwriting vptrs when a previously POD structure is
suddenly given a virtual method, or creating objects that crash on
practically any use by zero-ing out a member when its changed from
a const char* to a std::string, etc.
llvm-svn: 130299
Ted Kremenek