[clangd] Change index scope convention from "outer::inner" to "outer::inner::"

Global scope is "" (was "")
Top-level namespace scope is "ns::" (was "ns")
Nested namespace scope is "ns::ns::" (was "ns::ns")

This composes more naturally:
 - qname = scope + name
 - full scope = resolved scope + unresolved scope (D42073 was the trigger)
It removes a wart from the old way: "foo::" has one more separator than "".

Another alternative that has these properties is "::ns", but that lacks
the property that both the scope and the name are substrings of the
qname as produced by clang.

llvm-svn: 322996

1 files changed, 6 insertions, 8 deletions

diff --git a/clang-tools-extra/clangd/CodeComplete.cpp b/clang-tools-extra/clangd/CodeComplete.cpp
index 1a95b6ba6bf..ab8a22d6b45 100644
--- a/clang-tools-extra/clangd/CodeComplete.cpp
+++ b/clang-tools-extra/clangd/CodeComplete.cpp
@@ -313,7 +313,7 @@ llvm::Optional<SymbolID> getSymbolID(const CodeCompletionResult &R) {
 /// completion (e.g. "ns::ab?").
 struct SpecifiedScope {
   /// The scope specifier as written. For example, for completion "ns::ab?", the
-  /// written scope specifier is "ns".
+  /// written scope specifier is "ns::". Doesn't include leading "::".
   std::string Written;
   // If this scope specifier is recognized in Sema (e.g. as a namespace
   // context), this will be set to the fully qualfied name of the corresponding
@@ -321,8 +321,7 @@ struct SpecifiedScope {
   std::string Resolved;
 
   llvm::StringRef forIndex() {
-    llvm::StringRef Chosen = Resolved.empty() ? Written : Resolved;
-    return Chosen.trim(':');
+    return Resolved.empty() ? Written.ltrim('::') : Resolved;
   }
 };
 
@@ -631,15 +630,14 @@ SpecifiedScope getSpecifiedScope(Sema &S, const CXXScopeSpec &SS) {
   auto SpecifierRange = SS.getRange();
   Info.Written = Lexer::getSourceText(
       CharSourceRange::getCharRange(SpecifierRange), SM, clang::LangOptions());
+  if (!Info.Written.empty())
+    Info.Written += "::"; // Sema excludes the trailing ::.
   if (SS.isValid()) {
     DeclContext *DC = S.computeDeclContext(SS);
     if (auto *NS = llvm::dyn_cast<NamespaceDecl>(DC)) {
-      Info.Resolved = NS->getQualifiedNameAsString();
+      Info.Resolved = NS->getQualifiedNameAsString() + "::";
     } else if (llvm::dyn_cast<TranslationUnitDecl>(DC) != nullptr) {
-      Info.Resolved = "::";
-      // Sema does not include the suffix "::" in the range of SS, so we add
-      // it back here.
-      Info.Written = "::";
+      Info.Resolved = "";
     }
   }
   return Info;