commit 4384712b3a0aedd7c68d6abdb0407850f7b46c8b
author Larisse Voufo <lvoufo@google.com> Fri Jul 19 23:00:19 2013 +0000
committer Larisse Voufo <lvoufo@google.com> Fri Jul 19 23:00:19 2013 +0000
tree 289062be6437f8027bc6cb742333256f251e0171
parent 8c5d4078bb40642847164e7613828262d32db973

FIXME fix: improving diagnostics for template arguments deduction of class templates and explicit specializations
    This patch essentially removes all the FIXMEs following calls to DeduceTemplateArguments() that want to keep track of deduction failure info.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@186730 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Sema/SemaTemplate.cpp

diff --git a/lib/Sema/SemaTemplate.cpp b/lib/Sema/SemaTemplate.cpp
index 6f1ab19..7939c48 100644
--- a/lib/Sema/SemaTemplate.cpp
+++ b/lib/Sema/SemaTemplate.cpp
@@ -5925,13 +5925,13 @@
 ///
 /// \param Previous the set of declarations that may be specialized by
 /// this function specialization.
-bool
-Sema::CheckFunctionTemplateSpecialization(FunctionDecl *FD,
-                                 TemplateArgumentListInfo *ExplicitTemplateArgs,
-                                          LookupResult &Previous) {
+bool Sema::CheckFunctionTemplateSpecialization(
+    FunctionDecl *FD, TemplateArgumentListInfo *ExplicitTemplateArgs,
+    LookupResult &Previous) {
   // The set of function template specializations that could match this
   // explicit function template specialization.
   UnresolvedSet<8> Candidates;
+  TemplateSpecCandidateSet FailedCandidates(FD->getLocation());
 
   DeclContext *FDLookupContext = FD->getDeclContext()->getRedeclContext();
   for (LookupResult::iterator I = Previous.begin(), E = Previous.end();
@@ -5969,13 +5969,16 @@
       // Perform template argument deduction to determine whether we may be
       // specializing this template.
       // FIXME: It is somewhat wasteful to build
-      TemplateDeductionInfo Info(FD->getLocation());
+      TemplateDeductionInfo Info(FailedCandidates.getLocation());
       FunctionDecl *Specialization = 0;
       if (TemplateDeductionResult TDK
             = DeduceTemplateArguments(FunTmpl, ExplicitTemplateArgs, FT,
                                       Specialization, Info)) {
-        // FIXME: Template argument deduction failed; record why it failed, so
+        // Template argument deduction failed; record why it failed, so
         // that we can provide nifty diagnostics.
+        FailedCandidates.addCandidate()
+            .set(FunTmpl->getTemplatedDecl(),
+                 MakeDeductionFailureInfo(Context, TDK, Info));
         (void)TDK;
         continue;
       }
@@ -5986,14 +5989,14 @@
   }
 
   // Find the most specialized function template.
-  UnresolvedSetIterator Result
-    = getMostSpecialized(Candidates.begin(), Candidates.end(),
-                         TPOC_Other, 0, FD->getLocation(),
-                  PDiag(diag::err_function_template_spec_no_match)
-                    << FD->getDeclName(),
-                  PDiag(diag::err_function_template_spec_ambiguous)
-                    << FD->getDeclName() << (ExplicitTemplateArgs != 0),
-                  PDiag(diag::note_function_template_spec_matched));
+  UnresolvedSetIterator Result = getMostSpecialized(
+      Candidates.begin(), Candidates.end(), FailedCandidates, TPOC_Other, 0,
+      FD->getLocation(),
+      PDiag(diag::err_function_template_spec_no_match) << FD->getDeclName(),
+      PDiag(diag::err_function_template_spec_ambiguous)
+          << FD->getDeclName() << (ExplicitTemplateArgs != 0),
+      PDiag(diag::note_function_template_spec_matched));
+
   if (Result == Candidates.end())
     return true;
 
@@ -6812,6 +6815,7 @@
   //  instantiated from the member definition associated with its class
   //  template.
   UnresolvedSet<8> Matches;
+  TemplateSpecCandidateSet FailedCandidates(D.getIdentifierLoc());
   for (LookupResult::iterator P = Previous.begin(), PEnd = Previous.end();
        P != PEnd; ++P) {
     NamedDecl *Prev = *P;
@@ -6831,13 +6835,16 @@
     if (!FunTmpl)
       continue;
 
-    TemplateDeductionInfo Info(D.getIdentifierLoc());
+    TemplateDeductionInfo Info(FailedCandidates.getLocation());
     FunctionDecl *Specialization = 0;
     if (TemplateDeductionResult TDK
           = DeduceTemplateArguments(FunTmpl,
                                (HasExplicitTemplateArgs ? &TemplateArgs : 0),
                                     R, Specialization, Info)) {
-      // FIXME: Keep track of almost-matches?
+      // Keep track of almost-matches.
+      FailedCandidates.addCandidate()
+          .set(FunTmpl->getTemplatedDecl(),
+               MakeDeductionFailureInfo(Context, TDK, Info));
       (void)TDK;
       continue;
     }
@@ -6846,12 +6853,12 @@
   }
 
   // Find the most specialized function template specialization.
-  UnresolvedSetIterator Result
-    = getMostSpecialized(Matches.begin(), Matches.end(), TPOC_Other, 0,
-                         D.getIdentifierLoc(),
-                     PDiag(diag::err_explicit_instantiation_not_known) << Name,
-                     PDiag(diag::err_explicit_instantiation_ambiguous) << Name,
-                         PDiag(diag::note_explicit_instantiation_candidate));
+  UnresolvedSetIterator Result = getMostSpecialized(
+      Matches.begin(), Matches.end(), FailedCandidates, TPOC_Other, 0,
+      D.getIdentifierLoc(),
+      PDiag(diag::err_explicit_instantiation_not_known) << Name,
+      PDiag(diag::err_explicit_instantiation_ambiguous) << Name,
+      PDiag(diag::note_explicit_instantiation_candidate));
 
   if (Result == Matches.end())
     return true;