[clang] [clang-tools-extra] Handle recording inheritance for templates (PR #177273)

[via cfe-commits]

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@@ -1118,6 +1118,11 @@ const Symbol *SymbolCollector::addDeclaration(const NamedDecl &ND, SymbolID ID,
   if (ND.getAvailability() == AR_Deprecated)
     S.Flags |= Symbol::Deprecated;
 
+  if (isImplicitTemplateInstantiation(&ND)) {
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timon-ul wrote:

Actually the current documentation creation code is a bit  confusing to me. As you mentioned it is expensive so we want to avoid doing it when we can. But in the case of us being NOT indexed for code completion AND our indexing options say to NOT store all documentation we create the documentation but do not use it. I am unsure how frequent this is but it feels very wasteful. A quick glance makes it look like this might not be that rare? Do you think this warrants a cleanup? I feel like if I am already touching code here I can directly fix this too (or we can create a new TODO).

https://github.com/llvm/llvm-project/pull/177273