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.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@174039 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/include/clang/Basic/DiagnosticSemaKinds.td b/include/clang/Basic/DiagnosticSemaKinds.td
index f20bd06..2808226 100644
--- a/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/include/clang/Basic/DiagnosticSemaKinds.td
@@ -2334,6 +2334,8 @@
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 "
diff --git a/include/clang/Sema/Sema.h b/include/clang/Sema/Sema.h
index b77897a..47b2de8 100644
--- a/include/clang/Sema/Sema.h
+++ b/include/clang/Sema/Sema.h
@@ -5451,10 +5451,8 @@
/// \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 @@
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
diff --git a/include/clang/Sema/TemplateDeduction.h b/include/clang/Sema/TemplateDeduction.h
index e9a1449..3abb8f1 100644
--- a/include/clang/Sema/TemplateDeduction.h
+++ b/include/clang/Sema/TemplateDeduction.h
@@ -141,13 +141,16 @@
/// 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;
diff --git a/lib/Sema/SemaOverload.cpp b/lib/Sema/SemaOverload.cpp
index dbab739..82fe0c9 100644
--- a/lib/Sema/SemaOverload.cpp
+++ b/lib/Sema/SemaOverload.cpp
@@ -536,12 +536,16 @@
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 @@
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 @@
Result.Data = Info.Expression;
break;
- case Sema::TDK_NonDeducedMismatch:
+ case Sema::TDK_MiscellaneousDeductionFailure:
break;
}
@@ -608,10 +621,12 @@
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 @@
break;
// Unhandled
- case Sema::TDK_NonDeducedMismatch:
- case Sema::TDK_FailedOverloadResolution:
+ case Sema::TDK_MiscellaneousDeductionFailure:
break;
}
}
@@ -648,6 +662,8 @@
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 @@
return static_cast<DFIParamWithArguments*>(Data)->Param;
// Unhandled
- case Sema::TDK_NonDeducedMismatch:
- case Sema::TDK_FailedOverloadResolution:
+ case Sema::TDK_MiscellaneousDeductionFailure:
break;
}
@@ -670,24 +685,25 @@
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 @@
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 @@
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 @@
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 @@
case Sema::TDK_SubstitutionFailure:
case Sema::TDK_NonDeducedMismatch:
+ case Sema::TDK_MiscellaneousDeductionFailure:
return 3;
case Sema::TDK_InstantiationDepth:
diff --git a/lib/Sema/SemaTemplateDeduction.cpp b/lib/Sema/SemaTemplateDeduction.cpp
index 003d016..421633f 100644
--- a/lib/Sema/SemaTemplateDeduction.cpp
+++ b/lib/Sema/SemaTemplateDeduction.cpp
@@ -488,13 +488,19 @@
// 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 @@
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 @@
// 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 @@
// 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 @@
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 @@
// specialization, template argument deduction fails.
if (!ArgFunctionType.isNull() &&
!Context.hasSameType(ArgFunctionType, Specialization->getType()))
- return TDK_NonDeducedMismatch;
+ return TDK_MiscellaneousDeductionFailure;
return TDK_Success;
}
diff --git a/test/CXX/temp/temp.fct.spec/temp.deduct/temp.deduct.call/basic.cpp b/test/CXX/temp/temp.fct.spec/temp.deduct/temp.deduct.call/basic.cpp
index 90d2949..4f6dcc1 100644
--- a/test/CXX/temp/temp.fct.spec/temp.deduct/temp.deduct.call/basic.cpp
+++ b/test/CXX/temp/temp.fct.spec/temp.deduct/temp.deduct.call/basic.cpp
@@ -15,8 +15,7 @@
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 {
diff --git a/test/CXX/temp/temp.fct.spec/temp.deduct/temp.deduct.call/p1-0x.cpp b/test/CXX/temp/temp.fct.spec/temp.deduct/temp.deduct.call/p1-0x.cpp
index 8b192fa..cd1d9f1 100644
--- a/test/CXX/temp/temp.fct.spec/temp.deduct/temp.deduct.call/p1-0x.cpp
+++ b/test/CXX/temp/temp.fct.spec/temp.deduct/temp.deduct.call/p1-0x.cpp
@@ -53,8 +53,9 @@
}
+// 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>...);
diff --git a/test/SemaCXX/c99-variable-length-array.cpp b/test/SemaCXX/c99-variable-length-array.cpp
index de9c11e..bb620c7 100644
--- a/test/SemaCXX/c99-variable-length-array.cpp
+++ b/test/SemaCXX/c99-variable-length-array.cpp
@@ -64,8 +64,9 @@
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}}
diff --git a/test/SemaTemplate/instantiate-init.cpp b/test/SemaTemplate/instantiate-init.cpp
index adcc06f..6a1a57c 100644
--- a/test/SemaTemplate/instantiate-init.cpp
+++ b/test/SemaTemplate/instantiate-init.cpp
@@ -78,7 +78,7 @@
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 {
diff --git a/test/SemaTemplate/operator-template.cpp b/test/SemaTemplate/operator-template.cpp
index 777b0f5..30d6ccf 100644
--- a/test/SemaTemplate/operator-template.cpp
+++ b/test/SemaTemplate/operator-template.cpp
@@ -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); }
diff --git a/test/SemaTemplate/recursive-template-instantiation.cpp b/test/SemaTemplate/recursive-template-instantiation.cpp
index d6a0b24..fe37060 100644
--- a/test/SemaTemplate/recursive-template-instantiation.cpp
+++ b/test/SemaTemplate/recursive-template-instantiation.cpp
@@ -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}}
}