r174039 - Improve 'failed template argument deduction' diagnostic for the case where we
Richard Smith
richard-llvm at metafoo.co.uk
Wed Jan 30 21:19:50 PST 2013
Author: rsmith
Date: Wed Jan 30 23:19:49 2013
New Revision: 174039
URL: http://llvm.org/viewvc/llvm-project?rev=174039&view=rev
Log:
Improve 'failed template argument deduction' diagnostic for the case where we
have a direct mismatch between some component of the template and some
component of the argument. The diagnostic now says what the mismatch was, but
doesn't yet say which part of the template doesn't match.
Modified:
cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td
cfe/trunk/include/clang/Sema/Sema.h
cfe/trunk/include/clang/Sema/TemplateDeduction.h
cfe/trunk/lib/Sema/SemaOverload.cpp
cfe/trunk/lib/Sema/SemaTemplateDeduction.cpp
cfe/trunk/test/CXX/temp/temp.fct.spec/temp.deduct/temp.deduct.call/basic.cpp
cfe/trunk/test/CXX/temp/temp.fct.spec/temp.deduct/temp.deduct.call/p1-0x.cpp
cfe/trunk/test/SemaCXX/c99-variable-length-array.cpp
cfe/trunk/test/SemaTemplate/instantiate-init.cpp
cfe/trunk/test/SemaTemplate/operator-template.cpp
cfe/trunk/test/SemaTemplate/recursive-template-instantiation.cpp
Modified: cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td?rev=174039&r1=174038&r2=174039&view=diff
==============================================================================
--- cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td (original)
+++ cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td Wed Jan 30 23:19:49 2013
@@ -2334,6 +2334,8 @@ def note_ovl_candidate_disabled_by_enabl
def note_ovl_candidate_failed_overload_resolution : Note<
"candidate template ignored: couldn't resolve reference to overloaded "
"function %0">;
+def note_ovl_candidate_non_deduced_mismatch : Note<
+ "candidate template ignored: could not match %diff{$ against $|types}0,1">;
// Note that we don't treat templates differently for this diagnostic.
def note_ovl_candidate_arity : Note<"candidate "
Modified: cfe/trunk/include/clang/Sema/Sema.h
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Sema/Sema.h?rev=174039&r1=174038&r2=174039&view=diff
==============================================================================
--- cfe/trunk/include/clang/Sema/Sema.h (original)
+++ cfe/trunk/include/clang/Sema/Sema.h Wed Jan 30 23:19:49 2013
@@ -5451,10 +5451,8 @@ public:
/// \brief Substitution of the deduced template argument values
/// resulted in an error.
TDK_SubstitutionFailure,
- /// \brief Substitution of the deduced template argument values
- /// into a non-deduced context produced a type or value that
- /// produces a type that does not match the original template
- /// arguments provided.
+ /// \brief A non-depnedent component of the parameter did not match the
+ /// corresponding component of the argument.
TDK_NonDeducedMismatch,
/// \brief When performing template argument deduction for a function
/// template, there were too many call arguments.
@@ -5467,7 +5465,9 @@ public:
TDK_InvalidExplicitArguments,
/// \brief The arguments included an overloaded function name that could
/// not be resolved to a suitable function.
- TDK_FailedOverloadResolution
+ TDK_FailedOverloadResolution,
+ /// \brief Deduction failed; that's all we know.
+ TDK_MiscellaneousDeductionFailure
};
TemplateDeductionResult
Modified: cfe/trunk/include/clang/Sema/TemplateDeduction.h
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Sema/TemplateDeduction.h?rev=174039&r1=174038&r2=174039&view=diff
==============================================================================
--- cfe/trunk/include/clang/Sema/TemplateDeduction.h (original)
+++ cfe/trunk/include/clang/Sema/TemplateDeduction.h Wed Jan 30 23:19:49 2013
@@ -141,13 +141,16 @@ public:
/// TDK_SubstitutionFailure: this argument is the template
/// argument we were instantiating when we encountered an error.
///
- /// TDK_NonDeducedMismatch: this is the template argument
- /// provided in the source code.
+ /// TDK_NonDeducedMismatch: this is the component of the 'parameter'
+ /// of the deduction, directly provided in the source code.
TemplateArgument FirstArg;
/// \brief The second template argument to which the template
/// argument deduction failure refers.
///
+ /// TDK_NonDeducedMismatch: this is the mismatching component of the
+ /// 'argument' of the deduction, from which we are deducing arguments.
+ ///
/// FIXME: Finish documenting this.
TemplateArgument SecondArg;
Modified: cfe/trunk/lib/Sema/SemaOverload.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaOverload.cpp?rev=174039&r1=174038&r2=174039&view=diff
==============================================================================
--- cfe/trunk/lib/Sema/SemaOverload.cpp (original)
+++ cfe/trunk/lib/Sema/SemaOverload.cpp Wed Jan 30 23:19:49 2013
@@ -536,12 +536,16 @@ AmbiguousConversionSequence::copyFrom(co
namespace {
// Structure used by OverloadCandidate::DeductionFailureInfo to store
- // template parameter and template argument information.
- struct DFIParamWithArguments {
- TemplateParameter Param;
+ // template argument information.
+ struct DFIArguments {
TemplateArgument FirstArg;
TemplateArgument SecondArg;
};
+ // Structure used by OverloadCandidate::DeductionFailureInfo to store
+ // template parameter and template argument information.
+ struct DFIParamWithArguments : DFIArguments {
+ TemplateParameter Param;
+ };
}
/// \brief Convert from Sema's representation of template deduction information
@@ -567,6 +571,15 @@ static MakeDeductionFailureInfo(ASTConte
Result.Data = Info.Param.getOpaqueValue();
break;
+ case Sema::TDK_NonDeducedMismatch: {
+ // FIXME: Should allocate from normal heap so that we can free this later.
+ DFIArguments *Saved = new (Context) DFIArguments;
+ Saved->FirstArg = Info.FirstArg;
+ Saved->SecondArg = Info.SecondArg;
+ Result.Data = Saved;
+ break;
+ }
+
case Sema::TDK_Inconsistent:
case Sema::TDK_Underqualified: {
// FIXME: Should allocate from normal heap so that we can free this later.
@@ -592,7 +605,7 @@ static MakeDeductionFailureInfo(ASTConte
Result.Data = Info.Expression;
break;
- case Sema::TDK_NonDeducedMismatch:
+ case Sema::TDK_MiscellaneousDeductionFailure:
break;
}
@@ -608,10 +621,12 @@ void OverloadCandidate::DeductionFailure
case Sema::TDK_TooManyArguments:
case Sema::TDK_TooFewArguments:
case Sema::TDK_InvalidExplicitArguments:
+ case Sema::TDK_FailedOverloadResolution:
break;
case Sema::TDK_Inconsistent:
case Sema::TDK_Underqualified:
+ case Sema::TDK_NonDeducedMismatch:
// FIXME: Destroy the data?
Data = 0;
break;
@@ -626,8 +641,7 @@ void OverloadCandidate::DeductionFailure
break;
// Unhandled
- case Sema::TDK_NonDeducedMismatch:
- case Sema::TDK_FailedOverloadResolution:
+ case Sema::TDK_MiscellaneousDeductionFailure:
break;
}
}
@@ -648,6 +662,8 @@ OverloadCandidate::DeductionFailureInfo:
case Sema::TDK_TooManyArguments:
case Sema::TDK_TooFewArguments:
case Sema::TDK_SubstitutionFailure:
+ case Sema::TDK_NonDeducedMismatch:
+ case Sema::TDK_FailedOverloadResolution:
return TemplateParameter();
case Sema::TDK_Incomplete:
@@ -659,8 +675,7 @@ OverloadCandidate::DeductionFailureInfo:
return static_cast<DFIParamWithArguments*>(Data)->Param;
// Unhandled
- case Sema::TDK_NonDeducedMismatch:
- case Sema::TDK_FailedOverloadResolution:
+ case Sema::TDK_MiscellaneousDeductionFailure:
break;
}
@@ -670,24 +685,25 @@ OverloadCandidate::DeductionFailureInfo:
TemplateArgumentList *
OverloadCandidate::DeductionFailureInfo::getTemplateArgumentList() {
switch (static_cast<Sema::TemplateDeductionResult>(Result)) {
- case Sema::TDK_Success:
- case Sema::TDK_Invalid:
- case Sema::TDK_InstantiationDepth:
- case Sema::TDK_TooManyArguments:
- case Sema::TDK_TooFewArguments:
- case Sema::TDK_Incomplete:
- case Sema::TDK_InvalidExplicitArguments:
- case Sema::TDK_Inconsistent:
- case Sema::TDK_Underqualified:
- return 0;
+ case Sema::TDK_Success:
+ case Sema::TDK_Invalid:
+ case Sema::TDK_InstantiationDepth:
+ case Sema::TDK_TooManyArguments:
+ case Sema::TDK_TooFewArguments:
+ case Sema::TDK_Incomplete:
+ case Sema::TDK_InvalidExplicitArguments:
+ case Sema::TDK_Inconsistent:
+ case Sema::TDK_Underqualified:
+ case Sema::TDK_NonDeducedMismatch:
+ case Sema::TDK_FailedOverloadResolution:
+ return 0;
- case Sema::TDK_SubstitutionFailure:
- return static_cast<TemplateArgumentList*>(Data);
+ case Sema::TDK_SubstitutionFailure:
+ return static_cast<TemplateArgumentList*>(Data);
- // Unhandled
- case Sema::TDK_NonDeducedMismatch:
- case Sema::TDK_FailedOverloadResolution:
- break;
+ // Unhandled
+ case Sema::TDK_MiscellaneousDeductionFailure:
+ break;
}
return 0;
@@ -703,15 +719,16 @@ const TemplateArgument *OverloadCandidat
case Sema::TDK_TooFewArguments:
case Sema::TDK_InvalidExplicitArguments:
case Sema::TDK_SubstitutionFailure:
+ case Sema::TDK_FailedOverloadResolution:
return 0;
case Sema::TDK_Inconsistent:
case Sema::TDK_Underqualified:
- return &static_cast<DFIParamWithArguments*>(Data)->FirstArg;
+ case Sema::TDK_NonDeducedMismatch:
+ return &static_cast<DFIArguments*>(Data)->FirstArg;
// Unhandled
- case Sema::TDK_NonDeducedMismatch:
- case Sema::TDK_FailedOverloadResolution:
+ case Sema::TDK_MiscellaneousDeductionFailure:
break;
}
@@ -729,15 +746,16 @@ OverloadCandidate::DeductionFailureInfo:
case Sema::TDK_TooFewArguments:
case Sema::TDK_InvalidExplicitArguments:
case Sema::TDK_SubstitutionFailure:
+ case Sema::TDK_FailedOverloadResolution:
return 0;
case Sema::TDK_Inconsistent:
case Sema::TDK_Underqualified:
- return &static_cast<DFIParamWithArguments*>(Data)->SecondArg;
+ case Sema::TDK_NonDeducedMismatch:
+ return &static_cast<DFIArguments*>(Data)->SecondArg;
// Unhandled
- case Sema::TDK_NonDeducedMismatch:
- case Sema::TDK_FailedOverloadResolution:
+ case Sema::TDK_MiscellaneousDeductionFailure:
break;
}
@@ -8463,9 +8481,16 @@ void DiagnoseBadDeduction(Sema &S, Overl
return;
}
+ case Sema::TDK_NonDeducedMismatch:
+ // FIXME: Provide a source location to indicate what we couldn't match.
+ S.Diag(Fn->getLocation(), diag::note_ovl_candidate_non_deduced_mismatch)
+ << *Cand->DeductionFailure.getFirstArg()
+ << *Cand->DeductionFailure.getSecondArg();
+ return;
+
// TODO: diagnose these individually, then kill off
// note_ovl_candidate_bad_deduction, which is uselessly vague.
- case Sema::TDK_NonDeducedMismatch:
+ case Sema::TDK_MiscellaneousDeductionFailure:
S.Diag(Fn->getLocation(), diag::note_ovl_candidate_bad_deduction);
MaybeEmitInheritedConstructorNote(S, Fn);
return;
@@ -8643,6 +8668,7 @@ RankDeductionFailure(const OverloadCandi
case Sema::TDK_SubstitutionFailure:
case Sema::TDK_NonDeducedMismatch:
+ case Sema::TDK_MiscellaneousDeductionFailure:
return 3;
case Sema::TDK_InstantiationDepth:
Modified: cfe/trunk/lib/Sema/SemaTemplateDeduction.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaTemplateDeduction.cpp?rev=174039&r1=174038&r2=174039&view=diff
==============================================================================
--- cfe/trunk/lib/Sema/SemaTemplateDeduction.cpp (original)
+++ cfe/trunk/lib/Sema/SemaTemplateDeduction.cpp Wed Jan 30 23:19:49 2013
@@ -488,13 +488,19 @@ DeduceTemplateArguments(Sema &S,
// perform template argument deduction using its template
// arguments.
const RecordType *RecordArg = dyn_cast<RecordType>(Arg);
- if (!RecordArg)
+ if (!RecordArg) {
+ Info.FirstArg = TemplateArgument(QualType(Param, 0));
+ Info.SecondArg = TemplateArgument(Arg);
return Sema::TDK_NonDeducedMismatch;
+ }
ClassTemplateSpecializationDecl *SpecArg
= dyn_cast<ClassTemplateSpecializationDecl>(RecordArg->getDecl());
- if (!SpecArg)
+ if (!SpecArg) {
+ Info.FirstArg = TemplateArgument(QualType(Param, 0));
+ Info.SecondArg = TemplateArgument(Arg);
return Sema::TDK_NonDeducedMismatch;
+ }
// Perform template argument deduction for the template name.
if (Sema::TemplateDeductionResult Result
@@ -708,7 +714,7 @@ DeduceTemplateArguments(Sema &S,
if (NumParams != NumArgs &&
!(NumParams && isa<PackExpansionType>(Params[NumParams - 1])) &&
!(NumArgs && isa<PackExpansionType>(Args[NumArgs - 1])))
- return Sema::TDK_NonDeducedMismatch;
+ return Sema::TDK_MiscellaneousDeductionFailure;
// C++0x [temp.deduct.type]p10:
// Similarly, if P has a form that contains (T), then each parameter type
@@ -725,14 +731,14 @@ DeduceTemplateArguments(Sema &S,
// Make sure we have an argument.
if (ArgIdx >= NumArgs)
- return Sema::TDK_NonDeducedMismatch;
+ return Sema::TDK_MiscellaneousDeductionFailure;
if (isa<PackExpansionType>(Args[ArgIdx])) {
// C++0x [temp.deduct.type]p22:
// If the original function parameter associated with A is a function
// parameter pack and the function parameter associated with P is not
// a function parameter pack, then template argument deduction fails.
- return Sema::TDK_NonDeducedMismatch;
+ return Sema::TDK_MiscellaneousDeductionFailure;
}
if (Sema::TemplateDeductionResult Result
@@ -825,7 +831,7 @@ DeduceTemplateArguments(Sema &S,
// Make sure we don't have any extra arguments.
if (ArgIdx < NumArgs)
- return Sema::TDK_NonDeducedMismatch;
+ return Sema::TDK_MiscellaneousDeductionFailure;
return Sema::TDK_Success;
}
@@ -1772,7 +1778,7 @@ DeduceTemplateArguments(Sema &S,
if (Args[ArgIdx].isPackExpansion()) {
// FIXME: We follow the logic of C++0x [temp.deduct.type]p22 here,
// but applied to pack expansions that are template arguments.
- return Sema::TDK_NonDeducedMismatch;
+ return Sema::TDK_MiscellaneousDeductionFailure;
}
// Perform deduction for this Pi/Ai pair.
@@ -3365,7 +3371,7 @@ Sema::DeduceTemplateArguments(FunctionTe
// specialization, template argument deduction fails.
if (!ArgFunctionType.isNull() &&
!Context.hasSameType(ArgFunctionType, Specialization->getType()))
- return TDK_NonDeducedMismatch;
+ return TDK_MiscellaneousDeductionFailure;
return TDK_Success;
}
Modified: cfe/trunk/test/CXX/temp/temp.fct.spec/temp.deduct/temp.deduct.call/basic.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CXX/temp/temp.fct.spec/temp.deduct/temp.deduct.call/basic.cpp?rev=174039&r1=174038&r2=174039&view=diff
==============================================================================
--- cfe/trunk/test/CXX/temp/temp.fct.spec/temp.deduct/temp.deduct.call/basic.cpp (original)
+++ cfe/trunk/test/CXX/temp/temp.fct.spec/temp.deduct/temp.deduct.call/basic.cpp Wed Jan 30 23:19:49 2013
@@ -15,8 +15,7 @@ void test_f1(int *ip, float fv) {
f1(ip, fv);
}
-// TODO: this diagnostic can and should improve
-template<typename T> void f2(T*, T*); // expected-note {{candidate template ignored: failed template argument deduction}} \
+template<typename T> void f2(T*, T*); // expected-note {{candidate template ignored: could not match 'T *' against 'ConvToIntPtr'}} \
// expected-note{{candidate template ignored: deduced conflicting types for parameter 'T' ('int' vs. 'float')}}
struct ConvToIntPtr {
Modified: cfe/trunk/test/CXX/temp/temp.fct.spec/temp.deduct/temp.deduct.call/p1-0x.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CXX/temp/temp.fct.spec/temp.deduct/temp.deduct.call/p1-0x.cpp?rev=174039&r1=174038&r2=174039&view=diff
==============================================================================
--- cfe/trunk/test/CXX/temp/temp.fct.spec/temp.deduct/temp.deduct.call/p1-0x.cpp (original)
+++ cfe/trunk/test/CXX/temp/temp.fct.spec/temp.deduct/temp.deduct.call/p1-0x.cpp Wed Jan 30 23:19:49 2013
@@ -53,8 +53,9 @@ void test_simple_ref_deduction(int *ip,
}
+// FIXME: Use the template parameter names in this diagnostic.
template<typename ...Args1, typename ...Args2>
-typename get_nth_type<0, Args1...>::type first_arg_pair(pair<Args1, Args2>...); // expected-note{{candidate template ignored: failed template argument deduction}}
+typename get_nth_type<0, Args1...>::type first_arg_pair(pair<Args1, Args2>...); // expected-note{{candidate template ignored: could not match 'pair<type-parameter-0-0, type-parameter-0-1>' against 'int'}}
template<typename ...Args1, typename ...Args2>
typename get_nth_type<1, Args1...>::type second_arg_pair(pair<Args1, Args2>...);
Modified: cfe/trunk/test/SemaCXX/c99-variable-length-array.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaCXX/c99-variable-length-array.cpp?rev=174039&r1=174038&r2=174039&view=diff
==============================================================================
--- cfe/trunk/test/SemaCXX/c99-variable-length-array.cpp (original)
+++ cfe/trunk/test/SemaCXX/c99-variable-length-array.cpp Wed Jan 30 23:19:49 2013
@@ -64,8 +64,9 @@ X1<HasConstantValue> x1a;
X1<HasNonConstantValue> x1b; // expected-note{{in instantiation of}}
// Template argument deduction does not allow deducing a size from a VLA.
+// FIXME: This diagnostic should make it clear that the two 'N's are different entities!
template<typename T, unsigned N>
-void accept_array(T (&array)[N]); // expected-note{{candidate template ignored: failed template argument deduction}}
+void accept_array(T (&array)[N]); // expected-note{{candidate template ignored: could not match 'T [N]' against 'int [N]'}}
void test_accept_array(int N) {
int array[N]; // expected-warning{{variable length arrays are a C99 feature}}
Modified: cfe/trunk/test/SemaTemplate/instantiate-init.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaTemplate/instantiate-init.cpp?rev=174039&r1=174038&r2=174039&view=diff
==============================================================================
--- cfe/trunk/test/SemaTemplate/instantiate-init.cpp (original)
+++ cfe/trunk/test/SemaTemplate/instantiate-init.cpp Wed Jan 30 23:19:49 2013
@@ -78,7 +78,7 @@ namespace PR7985 {
template<int N> struct integral_c { };
template <typename T, int N>
- integral_c<N> array_lengthof(T (&x)[N]) { return integral_c<N>(); } // expected-note 2{{candidate template ignored: failed template argument deduction}}
+ integral_c<N> array_lengthof(T (&x)[N]) { return integral_c<N>(); } // expected-note 2{{candidate template ignored: could not match 'T [N]' against 'const Data<}}
template<typename T>
struct Data {
Modified: cfe/trunk/test/SemaTemplate/operator-template.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaTemplate/operator-template.cpp?rev=174039&r1=174038&r2=174039&view=diff
==============================================================================
--- cfe/trunk/test/SemaTemplate/operator-template.cpp (original)
+++ cfe/trunk/test/SemaTemplate/operator-template.cpp Wed Jan 30 23:19:49 2013
@@ -2,7 +2,7 @@
// Make sure we accept this
template<class X>struct A{typedef X Y;};
-template<class X>bool operator==(A<X>,typename A<X>::Y); // expected-note{{candidate template ignored: failed template argument deduction}}
+template<class X>bool operator==(A<X>,typename A<X>::Y); // expected-note{{candidate template ignored: could not match 'A<type-parameter-0-0>' against 'B<int> *'}}
int a(A<int> x) { return operator==(x,1); }
Modified: cfe/trunk/test/SemaTemplate/recursive-template-instantiation.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaTemplate/recursive-template-instantiation.cpp?rev=174039&r1=174038&r2=174039&view=diff
==============================================================================
--- cfe/trunk/test/SemaTemplate/recursive-template-instantiation.cpp (original)
+++ cfe/trunk/test/SemaTemplate/recursive-template-instantiation.cpp Wed Jan 30 23:19:49 2013
@@ -1,6 +1,6 @@
// RUN: %clang_cc1 -fsyntax-only -verify %s
-template<typename T> void f(T* t) { // expected-note{{failed template argument deduction}}
+template<typename T> void f(T* t) { // expected-note{{could not match 'T *' against 'int'}}
f(*t); // expected-error{{no matching function}}\
// expected-note 3{{requested here}}
}
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