[PATCH] Improve error reporting for SFINAE
Paul Fultz II
pfultz2 at yahoo.com
Mon Apr 6 13:37:50 PDT 2015
Added tests
REPOSITORY
rL LLVM
http://reviews.llvm.org/D8309
Files:
include/clang/Sema/TemplateDeduction.h
lib/Sema/SemaOverload.cpp
test/SemaCXX/sfinae-error-overload.cpp
test/SemaCXX/sfinae-error.cpp
Index: include/clang/Sema/TemplateDeduction.h
===================================================================
--- include/clang/Sema/TemplateDeduction.h
+++ include/clang/Sema/TemplateDeduction.h
@@ -68,8 +68,10 @@
/// \brief Take ownership of the SFINAE diagnostic.
void takeSFINAEDiagnostic(PartialDiagnosticAt &PD) {
assert(HasSFINAEDiagnostic);
- PD.first = SuppressedDiagnostics.front().first;
- PD.second.swap(SuppressedDiagnostics.front().second);
+ unsigned NumberOfDiagnostics = SuppressedDiagnostics.size();
+ PartialDiagnosticAt &PDiag = SuppressedDiagnostics[((NumberOfDiagnostics == 2) ? 1 : 0)];
+ PD.first = PDiag.first;
+ PD.second.swap(PDiag.second);
SuppressedDiagnostics.clear();
HasSFINAEDiagnostic = false;
}
@@ -98,8 +100,6 @@
/// \brief Add a new diagnostic to the set of diagnostics
void addSuppressedDiagnostic(SourceLocation Loc,
PartialDiagnostic PD) {
- if (HasSFINAEDiagnostic)
- return;
SuppressedDiagnostics.emplace_back(Loc, std::move(PD));
}
Index: lib/Sema/SemaOverload.cpp
===================================================================
--- lib/Sema/SemaOverload.cpp
+++ lib/Sema/SemaOverload.cpp
@@ -9105,6 +9105,16 @@
return;
}
+ // If the diagnsotics is already for overload candidate substitution
+ // failure, then just emit the diagnostics as is.
+ if (PDiag && (PDiag->second.getDiagID() ==
+ diag::note_ovl_candidate_substitution_failure ||
+ PDiag->second.getDiagID() ==
+ diag::note_ovl_candidate_disabled_by_enable_if)) {
+ S.Diag(PDiag->first, PDiag->second);
+ return;
+ }
+
// Format the SFINAE diagnostic into the argument string.
// FIXME: Add a general mechanism to include a PartialDiagnostic *'s
// formatted message in another diagnostic.
@@ -9116,7 +9126,7 @@
PDiag->second.EmitToString(S.getDiagnostics(), SFINAEArgString);
}
- S.Diag(Templated->getLocation(),
+ S.Diag(PDiag->first,
diag::note_ovl_candidate_substitution_failure)
<< TemplateArgString << SFINAEArgString << R;
MaybeEmitInheritedConstructorNote(S, Templated);
Index: test/SemaCXX/sfinae-error-overload.cpp
===================================================================
--- test/SemaCXX/sfinae-error-overload.cpp
+++ test/SemaCXX/sfinae-error-overload.cpp
@@ -0,0 +1,14 @@
+// RUN: %clang_cc1 -fsyntax-only %s -std=c++11 2>&1 | FileCheck %s
+template<class T> auto h(T x)->decltype(x.smurf()){return x.smurf();}
+void h() {}
+template<class T> auto g(T x)->decltype(h(x)){return h(x);}
+template<class T> auto f(T x)->decltype(g(x)){return g(x);}
+int main(){
+ f(3);
+}
+
+// CHECK: sfinae-error-overload.cpp:7:3: error: no matching function for call to 'f'
+// CHECK-NEXT: f(3);
+// CHECK: sfinae-error-overload.cpp:4:41: note: candidate template ignored: substitution failure [with T = int]: no matching function for call to 'h'
+// CHECK-NEXT: template<class T> auto g(T x)->decltype(h(x)){return h(x);}
+
Index: test/SemaCXX/sfinae-error.cpp
===================================================================
--- test/SemaCXX/sfinae-error.cpp
+++ test/SemaCXX/sfinae-error.cpp
@@ -0,0 +1,13 @@
+// RUN: %clang_cc1 -fsyntax-only %s -std=c++11 2>&1 | FileCheck --check-prefix=CHECK1 %s
+template<class T> auto h(T x)->decltype(x.smurf()){return x.smurf();}
+template<class T> auto g(T x)->decltype(h(x)){return h(x);}
+template<class T> auto f(T x)->decltype(g(x)){return g(x);}
+int main(){
+ f(3);
+}
+
+// CHECK1: sfinae-error.cpp:6:3: error: no matching function for call to 'f'
+// CHECK1: f(3);
+// CHECK1: sfinae-error.cpp:2:42: note: candidate template ignored: substitution failure [with T = int]: member reference base type 'int' is not a structure or union
+// CHECK1-NEXT: template<class T> auto h(T x)->decltype(x.smurf()){return x.smurf();}
+
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