[patch] Implementing -Wunused-local-typedefs
Nico Weber
thakis at chromium.org
Sat Jul 26 21:26:03 PDT 2014
I'm delighted to announce that, after almost two months of hard work, a new
patch set is available for review!
With these tantalizing features and fixes:
* TypedefNameDecls everywhere
* MarkAnyDeclReferenced() used throughout
* Instead of immediately emitting a diag, the TypedefNameDecls are stashed
in a set and the diagnostics for things in the set are emitted at end-of-TU
(except for TypedefNameDecls that have been referenced since then)
* It's now called -Wunused-local-typedef in singular, with an alias for the
gcc spelling
* More tests
On Tue, May 6, 2014 at 6:01 PM, Richard Smith <richard at metafoo.co.uk> wrote:
> def UnusedConstVariable : DiagGroup<"unused-const-variable">;
> def UnusedVariable : DiagGroup<"unused-variable",
> [UnusedConstVariable]>;
> +def UnusedLocalTypedefs : DiagGroup<"unused-local-typedefs">;
> def UnusedPropertyIvar : DiagGroup<"unused-property-ivar">;
>
> I'm a little uncomfortable about this flag being plural and the others
> being singular. GCC compatible, you say? =(
>
>
> +def warn_unused_local_typedefs : Warning<"unused typedef %0">,
>
> This one should definitely be singular.
>
> Reformatting of lib/Parse/ParseExprCXX.cpp looks unrelated. Feel free to
> commit that separately.
>
> + if (TypedefDecl* TD = dyn_cast_or_null<TypedefDecl>(SD))
>
> * should go on the right. Also, use 'auto' for a variable initialized from
> cast/dyn_cast/etc.
>
> Rather than calling setReferenced directly, please call
> Sema::MarkAnyDeclReferenced.
>
> +static bool ShouldDiagnoseUnusedDecl(const NamedDecl *D,
> + const DeclContext *DC) {
> [...]
> + if (!DC->isFunctionOrMethod())
> + return false;
>
> Please document what 'DC' is here; it's really not obvious. But it seems
> to me that you can replace DC here and below with just a bool
> WithinFunction.
>
Done.
> You can also remove it entirely and check whether D->getDeclContext() is a
> function, method, or local class.
>
> +void Sema::DiagnoseUnusedDecl(const NamedDecl *D, const DeclContext *DC) {
> + if (DC->isFunctionOrMethod())
> + if (const RecordDecl *RD = dyn_cast<RecordDecl>(D))
> + for (auto *TmpD : RD->decls())
> + if (isa<TypedefDecl>(TmpD) || isa<RecordDecl>(TmpD))
> + DiagnoseUnusedDecl(cast<NamedDecl>(TmpD), DC);
>
> This would make more sense as a layer between ActOnPopScope and
> DiagnoseUnusedDecl.
>
Done.
> A comment explaining why we only do this within a function or method would
> help ("within a function or method, we defer these checks until the end of
> the surrounding scope").
>
> Also, this isn't necessarily correct in C++14, since a local type's
> members can be first used once we've already left the function:
>
> auto f() {
> struct S { typedef int t; };
> return S();
> }
> auto x = f();
> decltype(x)::t y;
>
> What happens if the local type is used as an argument to a function
> template, which in turn uses the typedef? Can we really diagnose this
> before end-of-TU?
>
Done.
> + else if (isa<TypedefDecl>(D)) // TODO: Warn on unused c++11 aliases
> too?
> + DiagID = diag::warn_unused_local_typedefs;
>
> Yes, please change this to TypedefNameDecl (throughout the patch). It
> doesn't make sense to handle these differently, since one can be a
> redeclaration of the other.
>
Done.
>
> Index: lib/Sema/SemaTemplateInstantiateDecl.cpp
> ===================================================================
> --- lib/Sema/SemaTemplateInstantiateDecl.cpp (revision 207920)
> +++ lib/Sema/SemaTemplateInstantiateDecl.cpp (working copy)
> @@ -3651,7 +3651,7 @@
> if (!NewVar->isInvalidDecl() &&
> NewVar->getDeclContext()->isFunctionOrMethod() && !NewVar->isUsed()
> &&
> OldVar->getType()->isDependentType())
> - DiagnoseUnusedDecl(NewVar);
> + DiagnoseUnusedDecl(NewVar, NewVar->getDeclContext());
>
> Hmm, why do we diagnose unused decls from template instantiation at all?
>
r103362 added this, r133580 tweaked it some. Can you think of an example
where a template-local typedef is unused only in some instantiations of
that template?
>
> On Sat, May 3, 2014 at 10:37 PM, Nico Weber <thakis at chromium.org> wrote:
>
>> With one more setReferenced() call (in SemaCXXScopeSpec.cpp). This
>> version has successfully compiled several thousand files of chromium
>> (all that I've tried so far).
>>
>> On Sat, May 3, 2014 at 6:35 PM, Nico Weber <thakis at chromium.org> wrote:
>> > About point 2: The patch currently incorrectly warns on the "v" typedef
>> in:
>> >
>> > template <class T> struct V { typedef int iterator; };
>> > void f() {
>> > typedef V<int> v;
>> > v::iterator it;
>> > }
>> >
>> > So there's at least one more place where I need to insert a
>> > setReferenced() I'll send an updated version once I found where, but
>> > I'm thankful for comments on the overall approach in the meantime too.
>> >
>> > On Sat, May 3, 2014 at 6:08 PM, Nico Weber <thakis at chromium.org> wrote:
>> >> (Forgot to say: This is also PR18265.)
>> >>
>> >> On Sat, May 3, 2014 at 6:07 PM, Nico Weber <thakis at chromium.org>
>> wrote:
>> >>> Hi,
>> >>>
>> >>> gcc has a warning -Wunused-local-typedefs that warns on unused local
>> >>> typedefs. Inspired by r207870, I thought it'd be nice if clang had
>> >>> this warning too. This warning requires the following three things:
>> >>>
>> >>>
>> >>> 1.) A bit to track if a typedef has been referenced.
>> >>>
>> >>> Decl already has isUsed and isReferenced, but they don't seem to be
>> >>> used for TypedefDecls, so I'm just using isReferenced on TypedefDecls
>> >>> for this.
>> >>>
>> >>>
>> >>> 2.) Setting that bit on typedefs that are used.
>> >>>
>> >>> The three strategies I can think of:
>> >>> a.) Do this in Sema::DiagnoseUseOfDecl(), this seems to be already
>> >>> called for decls all over the place, and an "if isa<TypedefDecl>(D)
>> >>> D->setReferenced()" seems to do the trick.
>> >>> b.) Do this in LookupName
>> >>> c.) Do this explicitly in the places where it's actually necessary.
>> >>>
>> >>> The attached patch goes with the last approach. The three places I
>> >>> found where it's needed are Sema::getTypeName(), Sema::ClassifyName(),
>> >>> and Sema::LookupInlineAsmField(). The first two are called by the
>> >>> parser for almost everything, while the third is called for references
>> >>> to structs from MS inline assembly. That last one is a bit scary as it
>> >>> means it's possible that there are other places this is needed that I
>> >>> missed.
>> >>>
>> >>>
>> >>> 3.) A way to check all typedefs in a scope when that scope ends.
>> >>>
>> >>> I added this to Sema::ActOnPopScope() which is where the
>> >>> unused-variable and unused-label warnings are created. This works
>> >>> well, but to catch the unused local typedef in
>> >>>
>> >>> {
>> >>> struct A {
>> >>> struct B { typedef int SoDeep; };
>> >>> };
>> >>> }
>> >>>
>> >>> it means that that code now needs to recurse into all RecordDecl in a
>> >>> scope, which it didn't need to do previously.
>> >>>
>> >>>
>> >>> Let me know how badly I've chosen in each instance :-)
>> >>>
>> >>> Thanks,
>> >>> Nico
>> >>>
>> >>> ps: If this goes in, a follow-up question is if this should warn on
>> >>> unused C++11 type aliases too – it'd just require
>> >>> s/TypedefDecl/TypedefNameDecl/ in two places in the patch, so it
>> >>> should be an easy follow-up.
>>
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.llvm.org/pipermail/cfe-commits/attachments/20140726/c0324f57/attachment.html>
-------------- next part --------------
Index: include/clang/Basic/DiagnosticGroups.td
===================================================================
--- include/clang/Basic/DiagnosticGroups.td (revision 214046)
+++ include/clang/Basic/DiagnosticGroups.td (working copy)
@@ -401,6 +401,7 @@
def UnusedConstVariable : DiagGroup<"unused-const-variable">;
def UnusedVariable : DiagGroup<"unused-variable",
[UnusedConstVariable]>;
+def UnusedLocalTypedef : DiagGroup<"unused-local-typedef">;
def UnusedPropertyIvar : DiagGroup<"unused-property-ivar">;
def UsedButMarkedUnused : DiagGroup<"used-but-marked-unused">;
def UserDefinedLiterals : DiagGroup<"user-defined-literals">;
@@ -523,7 +524,7 @@
[UnusedArgument, UnusedFunction, UnusedLabel,
// UnusedParameter, (matches GCC's behavior)
// UnusedMemberFunction, (clean-up llvm before enabling)
- UnusedPrivateField,
+ UnusedPrivateField, UnusedLocalTypedef,
UnusedValue, UnusedVariable, UnusedPropertyIvar]>,
DiagCategory<"Unused Entity Issue">;
@@ -617,6 +618,8 @@
[IntConversion]>; // -Wint-conversions = -Wint-conversion
def : DiagGroup<"vector-conversions",
[VectorConversion]>; // -Wvector-conversions = -Wvector-conversion
+def : DiagGroup<"unused-local-typedefs", [UnusedLocalTypedef]>;
+ // -Wunused-local-typedefs = -Wunused-local-typedef
// A warning group for warnings that we want to have on by default in clang,
// but which aren't on by default in GCC.
Index: include/clang/Basic/DiagnosticSemaKinds.td
===================================================================
--- include/clang/Basic/DiagnosticSemaKinds.td (revision 214046)
+++ include/clang/Basic/DiagnosticSemaKinds.td (working copy)
@@ -175,6 +175,9 @@
InGroup<UnusedParameter>, DefaultIgnore;
def warn_unused_variable : Warning<"unused variable %0">,
InGroup<UnusedVariable>, DefaultIgnore;
+def warn_unused_local_typedef : Warning<
+ "unused %select{typedef|type alias}0 %1">,
+ InGroup<UnusedLocalTypedef>, DefaultIgnore;
def warn_unused_property_backing_ivar :
Warning<"ivar %0 which backs the property is not "
"referenced in this property's accessor">,
Index: include/clang/Sema/Sema.h
===================================================================
--- include/clang/Sema/Sema.h (revision 214046)
+++ include/clang/Sema/Sema.h (working copy)
@@ -385,16 +385,18 @@
/// FieldCollector - Collects CXXFieldDecls during parsing of C++ classes.
std::unique_ptr<CXXFieldCollector> FieldCollector;
+ /// \brief Set containing all declared private fields that are not used.
typedef llvm::SmallSetVector<const NamedDecl*, 16> NamedDeclSetType;
-
- /// \brief Set containing all declared private fields that are not used.
NamedDeclSetType UnusedPrivateFields;
- typedef llvm::SmallPtrSet<const CXXRecordDecl*, 8> RecordDeclSetTy;
+ /// \brief Set containing all typedefs that are likely unused.
+ llvm::SmallSetVector<const TypedefNameDecl *, 4>
+ UnusedLocalTypedefNameCandidates;
/// PureVirtualClassDiagSet - a set of class declarations which we have
/// emitted a list of pure virtual functions. Used to prevent emitting the
/// same list more than once.
+ typedef llvm::SmallPtrSet<const CXXRecordDecl*, 8> RecordDeclSetTy;
std::unique_ptr<RecordDeclSetTy> PureVirtualClassDiagSet;
/// ParsingInitForAutoVars - a set of declarations with auto types for which
@@ -3187,7 +3189,7 @@
/// DiagnoseUnusedExprResult - If the statement passed in is an expression
/// whose result is unused, warn.
void DiagnoseUnusedExprResult(const Stmt *S);
- void DiagnoseUnusedDecl(const NamedDecl *ND);
+ void DiagnoseUnusedDecl(const NamedDecl *ND, bool WithinFunction);
/// Emit \p DiagID if statement located on \p StmtLoc has a suspicious null
/// statement as a \p Body, and it is located on the same line.
Index: lib/Sema/Sema.cpp
===================================================================
--- lib/Sema/Sema.cpp (revision 214046)
+++ lib/Sema/Sema.cpp (working copy)
@@ -823,6 +823,15 @@
checkUndefinedButUsed(*this);
}
+ if (!Diags.isIgnored(diag::warn_unused_local_typedef, SourceLocation())) {
+ for (const TypedefNameDecl *TD : UnusedLocalTypedefNameCandidates) {
+ if (TD->isReferenced())
+ continue;
+ Diag(TD->getLocation(), diag::warn_unused_local_typedef)
+ << isa<TypeAliasDecl>(TD) << TD->getDeclName();
+ }
+ }
+
if (!Diags.isIgnored(diag::warn_unused_private_field, SourceLocation())) {
RecordCompleteMap RecordsComplete;
RecordCompleteMap MNCComplete;
Index: lib/Sema/SemaCXXScopeSpec.cpp
===================================================================
--- lib/Sema/SemaCXXScopeSpec.cpp (revision 214046)
+++ lib/Sema/SemaCXXScopeSpec.cpp (working copy)
@@ -612,6 +612,9 @@
}
}
+ if (auto *TD = dyn_cast_or_null<TypedefNameDecl>(SD))
+ MarkAnyDeclReferenced(TD->getLocation(), TD, /*OdrUse=*/false);
+
// If we're just performing this lookup for error-recovery purposes,
// don't extend the nested-name-specifier. Just return now.
if (ErrorRecoveryLookup)
Index: lib/Sema/SemaDecl.cpp
===================================================================
--- lib/Sema/SemaDecl.cpp (revision 214046)
+++ lib/Sema/SemaDecl.cpp (working copy)
@@ -377,6 +377,7 @@
DiagnoseUseOfDecl(IIDecl, NameLoc);
T = Context.getTypeDeclType(TD);
+ MarkAnyDeclReferenced(TD->getLocation(), TD, /*OdrUse=*/false);
// NOTE: avoid constructing an ElaboratedType(Loc) if this is a
// constructor or destructor name (in such a case, the scope specifier
@@ -925,6 +926,7 @@
NamedDecl *FirstDecl = (*Result.begin())->getUnderlyingDecl();
if (TypeDecl *Type = dyn_cast<TypeDecl>(FirstDecl)) {
DiagnoseUseOfDecl(Type, NameLoc);
+ MarkAnyDeclReferenced(Type->getLocation(), Type, /*OdrUse=*/false);
QualType T = Context.getTypeDeclType(Type);
if (SS.isNotEmpty())
return buildNestedType(*this, SS, T, NameLoc);
@@ -1382,7 +1384,7 @@
UnusedFileScopedDecls.push_back(D);
}
-static bool ShouldDiagnoseUnusedDecl(const NamedDecl *D) {
+static bool ShouldDiagnoseUnusedDecl(const NamedDecl *D, bool WithinFunction) {
if (D->isInvalidDecl())
return false;
@@ -1392,10 +1394,17 @@
if (isa<LabelDecl>(D))
return true;
+
+ // Except for labels, we only care about unused decls that are local to
+ // functions.
+ if (!WithinFunction)
+ return false;
+
+ if (isa<TypedefNameDecl>(D))
+ return true;
// White-list anything that isn't a local variable.
- if (!isa<VarDecl>(D) || isa<ParmVarDecl>(D) || isa<ImplicitParamDecl>(D) ||
- !D->getDeclContext()->isFunctionOrMethod())
+ if (!isa<VarDecl>(D) || isa<ParmVarDecl>(D) || isa<ImplicitParamDecl>(D))
return false;
// Types of valid local variables should be complete, so this should succeed.
@@ -1458,11 +1467,28 @@
return;
}
+static void DiagnoseUnusedNestedTypedefs(Sema &S, const RecordDecl *D,
+ bool WithinFunction) {
+ for (auto *TmpD : D->decls()) {
+ if (const auto* T = dyn_cast<TypedefNameDecl>(TmpD))
+ S.DiagnoseUnusedDecl(T, WithinFunction);
+ else if(const auto *R = dyn_cast<RecordDecl>(TmpD))
+ DiagnoseUnusedNestedTypedefs(S, R, WithinFunction);
+ }
+}
+
/// DiagnoseUnusedDecl - Emit warnings about declarations that are not used
/// unless they are marked attr(unused).
-void Sema::DiagnoseUnusedDecl(const NamedDecl *D) {
- if (!ShouldDiagnoseUnusedDecl(D))
+void Sema::DiagnoseUnusedDecl(const NamedDecl *D, bool WithinFunction) {
+ if (!ShouldDiagnoseUnusedDecl(D, WithinFunction))
return;
+
+ if (auto* TD = dyn_cast<TypedefNameDecl>(D)) {
+ // typedefs can be referenced later on, so the diagnostics are emitted
+ // at end-of-translation-unit.
+ UnusedLocalTypedefNameCandidates.insert(TD);
+ return;
+ }
FixItHint Hint;
GenerateFixForUnusedDecl(D, Context, Hint);
@@ -1502,8 +1528,12 @@
if (!D->getDeclName()) continue;
// Diagnose unused variables in this scope.
- if (!S->hasUnrecoverableErrorOccurred())
- DiagnoseUnusedDecl(D);
+ if (!S->hasUnrecoverableErrorOccurred()) {
+ bool WithinFunction = D->getDeclContext()->isFunctionOrMethod();
+ DiagnoseUnusedDecl(D, WithinFunction);
+ if (const auto *RD = dyn_cast<RecordDecl>(D))
+ DiagnoseUnusedNestedTypedefs(*this, RD, WithinFunction);
+ }
// If this was a forward reference to a label, verify it was defined.
if (LabelDecl *LD = dyn_cast<LabelDecl>(D))
Index: lib/Sema/SemaStmtAsm.cpp
===================================================================
--- lib/Sema/SemaStmtAsm.cpp (revision 214046)
+++ lib/Sema/SemaStmtAsm.cpp (working copy)
@@ -443,8 +443,10 @@
NamedDecl *FoundDecl = BaseResult.getFoundDecl();
if (VarDecl *VD = dyn_cast<VarDecl>(FoundDecl))
RT = VD->getType()->getAs<RecordType>();
- else if (TypedefNameDecl *TD = dyn_cast<TypedefNameDecl>(FoundDecl))
+ else if (TypedefNameDecl *TD = dyn_cast<TypedefNameDecl>(FoundDecl)) {
+ MarkAnyDeclReferenced(TD->getLocation(), TD, /*OdrUse=*/false);
RT = TD->getUnderlyingType()->getAs<RecordType>();
+ }
else if (TypeDecl *TD = dyn_cast<TypeDecl>(FoundDecl))
RT = TD->getTypeForDecl()->getAs<RecordType>();
if (!RT)
Index: lib/Sema/SemaTemplateInstantiateDecl.cpp
===================================================================
--- lib/Sema/SemaTemplateInstantiateDecl.cpp (revision 214046)
+++ lib/Sema/SemaTemplateInstantiateDecl.cpp (working copy)
@@ -3653,7 +3653,7 @@
if (!NewVar->isInvalidDecl() &&
NewVar->getDeclContext()->isFunctionOrMethod() && !NewVar->isUsed() &&
OldVar->getType()->isDependentType())
- DiagnoseUnusedDecl(NewVar);
+ DiagnoseUnusedDecl(NewVar, NewVar->getDeclContext()->isFunctionOrMethod());
}
/// \brief Instantiate the initializer of a variable.
Index: test/Misc/ast-dump-color.cpp
===================================================================
--- test/Misc/ast-dump-color.cpp (revision 214046)
+++ test/Misc/ast-dump-color.cpp (working copy)
@@ -89,7 +89,7 @@
//CHECK: {{^}}[[Blue]]| `-[[RESET]][[BLUE]]GuardedByAttr[[RESET]][[Yellow]] 0x{{[0-9a-fA-F]*}}[[RESET]] <[[Yellow]]col:29[[RESET]], [[Yellow]]col:43[[RESET]]>{{$}}
//CHECK: {{^}}[[Blue]]| `-[[RESET]][[MAGENTA]]DeclRefExpr[[RESET]][[Yellow]] 0x{{[0-9a-fA-F]*}}[[RESET]] <[[Yellow]]col:40[[RESET]]> [[Green]]'class Mutex':'class Mutex'[[RESET]][[Cyan]] lvalue[[RESET]][[Cyan]][[RESET]] [[GREEN]]Var[[RESET]][[Yellow]] 0x{{[0-9a-fA-F]*}}[[RESET]][[CYAN]] 'mu1'[[RESET]] [[Green]]'class Mutex':'class Mutex'[[RESET]]{{$}}
//CHECK: {{^}}[[Blue]]|-[[RESET]][[GREEN]]CXXRecordDecl[[RESET]][[Yellow]] 0x{{[0-9a-fA-F]*}}[[RESET]] <[[Yellow]]line:28:1[[RESET]], [[Yellow]]line:30:1[[RESET]]> [[Yellow]]line:28:8[[RESET]] struct[[CYAN]] Invalid[[RESET]] definition
-//CHECK: {{^}}[[Blue]]| |-[[RESET]][[GREEN]]CXXRecordDecl[[RESET]][[Yellow]] 0x{{[0-9a-fA-F]*}}[[RESET]] <[[Yellow]]col:1[[RESET]], [[Yellow]]col:8[[RESET]]> [[Yellow]]col:8[[RESET]] implicit struct[[CYAN]] Invalid[[RESET]]
+//CHECK: {{^}}[[Blue]]| |-[[RESET]][[GREEN]]CXXRecordDecl[[RESET]][[Yellow]] 0x{{[0-9a-fA-F]*}}[[RESET]] <[[Yellow]]col:1[[RESET]], [[Yellow]]col:8[[RESET]]> [[Yellow]]col:8[[RESET]] implicit referenced struct[[CYAN]] Invalid[[RESET]]
//CHECK: {{^}}[[Blue]]| |-[[RESET]][[GREEN]]CXXConstructorDecl[[RESET]][[Yellow]] 0x{{[0-9a-fA-F]*}}[[RESET]] <[[Yellow]]line:29:3[[RESET]], [[Yellow]]col:42[[RESET]]> [[Yellow]]col:29[[RESET]] invalid[[CYAN]] Invalid[[RESET]] [[Green]]'void (int)'[[RESET]]
//CHECK: {{^}}[[Blue]]| | |-[[RESET]][[GREEN]]ParmVarDecl[[RESET]][[Yellow]] 0x{{[0-9a-fA-F]*}}[[RESET]] <[[Yellow]]col:37[[RESET]], [[Yellow]]<invalid sloc>[[RESET]]> [[Yellow]]col:42[[RESET]] invalid [[Green]]'int'[[RESET]]
//CHECK: {{^}}[[Blue]]| | `-[[RESET]][[BLUE]]NoInlineAttr[[RESET]][[Yellow]] 0x{{[0-9a-fA-F]*}}[[RESET]] <[[Yellow]]col:18[[RESET]]>
Index: test/SemaCXX/implicit-exception-spec.cpp
===================================================================
--- test/SemaCXX/implicit-exception-spec.cpp (revision 214046)
+++ test/SemaCXX/implicit-exception-spec.cpp (working copy)
@@ -1,4 +1,4 @@
-// RUN: %clang_cc1 -fsyntax-only -fcxx-exceptions -verify -std=c++11 -Wall %s
+// RUN: %clang_cc1 -fsyntax-only -fcxx-exceptions -verify -std=c++11 -Wall -Wno-unused-local-typedefs %s
template<bool b> struct ExceptionIf { static int f(); };
template<> struct ExceptionIf<false> { typedef int f; };
Index: test/SemaCXX/warn-unused-filescoped.cpp
===================================================================
--- test/SemaCXX/warn-unused-filescoped.cpp (revision 214046)
+++ test/SemaCXX/warn-unused-filescoped.cpp (working copy)
@@ -1,5 +1,5 @@
-// RUN: %clang_cc1 -fsyntax-only -verify -Wunused -Wunused-member-function -Wno-c++11-extensions -std=c++98 %s
-// RUN: %clang_cc1 -fsyntax-only -verify -Wunused -Wunused-member-function -std=c++11 %s
+// RUN: %clang_cc1 -fsyntax-only -verify -Wunused -Wunused-member-function -Wno-unused-local-typedefs -Wno-c++11-extensions -std=c++98 %s
+// RUN: %clang_cc1 -fsyntax-only -verify -Wunused -Wunused-member-function -Wno-unused-local-typedefs -std=c++11 %s
#ifdef HEADER
Index: test/SemaCXX/warn-unused-local-typedefs.cpp
===================================================================
--- test/SemaCXX/warn-unused-local-typedefs.cpp (revision 0)
+++ test/SemaCXX/warn-unused-local-typedefs.cpp (working copy)
@@ -0,0 +1,116 @@
+// RUN: %clang_cc1 -fsyntax-only -Wunused-local-typedefs -verify -std=c++1y -fasm-blocks %s
+
+struct S {
+ typedef int Foo; // no diag
+};
+
+namespace N {
+ typedef int Foo; // no diag
+ typedef int Foo2; // no diag
+}
+
+template <class T> class Vec {};
+
+typedef int global_foo; // no diag (?)
+
+void f() {
+ typedef int foo0; // expected-warning {{unused typedef 'foo0'}}
+ using foo0alias = int ; // expected-warning {{unused type alias 'foo0alias'}}
+
+ typedef int foo1 __attribute__((unused)); // no diag
+
+ typedef int foo2;
+ {
+ typedef int foo2; // expected-warning {{unused typedef 'foo2'}}
+ }
+ typedef foo2 foo3; // expected-warning {{unused typedef 'foo3'}}
+
+ typedef int foo2_2; // expected-warning {{unused typedef 'foo2_2'}}
+ {
+ typedef int foo2_2;
+ typedef foo2_2 foo3_2; // expected-warning {{unused typedef 'foo3_2'}}
+ }
+
+ typedef int foo4;
+ foo4 the_thing;
+
+ typedef int* foo5;
+ typedef foo5* foo6; // no diag
+ foo6 *myptr;
+
+ struct S2 {
+ typedef int Foo; // no diag
+ typedef int Foo2; // expected-warning {{unused typedef 'Foo2'}}
+
+ struct Deeper {
+ typedef int DeepFoo; // expected-warning {{unused typedef 'DeepFoo'}}
+ };
+ };
+
+ S2::Foo s2foo;
+
+ typedef struct {} foostruct; // expected-warning {{unused typedef 'foostruct'}}
+
+ typedef struct {} foostruct2; // no diag
+ foostruct2 fs2;
+
+ typedef int vecint; // no diag
+ Vec<vecint> v;
+
+ N::Foo nfoo;
+
+ // FIXME: typedef that's only used in a constexpr
+}
+
+int printf(char const *, ...);
+
+void test() {
+ typedef signed long int superint; // no diag
+ printf("%f", (superint) 42);
+
+ typedef signed long int superint2; // no diag
+ printf("%f", static_cast<superint2>(42));
+}
+
+template <class T>
+void template_fun(T t) {
+ typedef int foo; // expected-warning {{unused typedef 'foo'}}
+}
+void template_fun_user() {
+ template_fun(3);
+}
+
+
+void typedef_in_nested_name() {
+ typedef struct {
+ typedef int Foo;
+ } A;
+ A::Foo adsf;
+
+ using A2 = struct {
+ typedef int Foo;
+ };
+ A2::Foo adsf2;
+}
+
+void use_in_asm() {
+ typedef struct {
+ int a;
+ int b;
+ } A;
+ __asm mov eax, [eax].A.b
+
+ using Alias = struct {
+ int a;
+ int b;
+ };
+ __asm mov eax, [eax].Alias.b
+}
+
+// Local typedefs can be used after the scope they were in has closed:
+auto sneaky() {
+ struct S { typedef int t; };
+ return S();
+}
+auto x = sneaky();
+decltype(x)::t y;
More information about the cfe-commits
mailing list