[CodeCompletion] Signature help for braced constructor calls

Implementation is based on the "expected type" as used for
designated-initializers in braced init lists. This means it can deduce the type
in some cases where it's not written:

  void foo(Widget);
  foo({ /*help here*/ });

Only basic constructor calls are in scope of this patch, excluded are:
 - aggregate initialization (no help is offered for aggregates)
 - initializer_list initialization (no help is offered for these constructors)

Fixes https://github.com/clangd/clangd/issues/306

Differential Revision: https://reviews.llvm.org/D116317

1 files changed, 6 insertions, 5 deletions

diff --git a/clang/tools/libclang/CIndexCodeCompletion.cpp b/clang/tools/libclang/CIndexCodeCompletion.cpp
index 044cac9..0d75970 100644
--- a/clang/tools/libclang/CIndexCodeCompletion.cpp
+++ b/clang/tools/libclang/CIndexCodeCompletion.cpp
@@ -656,14 +656,15 @@ namespace {
     void ProcessOverloadCandidates(Sema &S, unsigned CurrentArg,
                                    OverloadCandidate *Candidates,
                                    unsigned NumCandidates,
-                                   SourceLocation OpenParLoc) override {
+                                   SourceLocation OpenParLoc,
+                                   bool Braced) override {
       StoredResults.reserve(StoredResults.size() + NumCandidates);
       for (unsigned I = 0; I != NumCandidates; ++I) {
-        CodeCompletionString *StoredCompletion
-          = Candidates[I].CreateSignatureString(CurrentArg, S, getAllocator(),
+        CodeCompletionString *StoredCompletion =
+            Candidates[I].CreateSignatureString(CurrentArg, S, getAllocator(),
                                                 getCodeCompletionTUInfo(),
-                                                includeBriefComments());
-        
+                                                includeBriefComments(), Braced);
+
         CXCompletionResult R;
         R.CursorKind = CXCursor_OverloadCandidate;
         R.CompletionString = StoredCompletion;