Revert "[clang] Implement instantiation context note for checking template parameters (#126088)"

This reverts commit a24523ac8dc07f3478311a5969184b922b520395.

This is causing significant compile-time regressions for C++ code, see:
https://github.com/llvm/llvm-project/pull/126088#issuecomment-2704874202

1 files changed, 8 insertions, 16 deletions

diff --git a/clang/lib/Frontend/FrontendActions.cpp b/clang/lib/Frontend/FrontendActions.cpp
index 60e103e..1ea4a2e 100644
--- a/clang/lib/Frontend/FrontendActions.cpp
+++ b/clang/lib/Frontend/FrontendActions.cpp
@@ -403,8 +403,7 @@ public:
   }
 
 private:
-  static std::optional<std::string>
-  toString(CodeSynthesisContext::SynthesisKind Kind) {
+  static std::string toString(CodeSynthesisContext::SynthesisKind Kind) {
     switch (Kind) {
     case CodeSynthesisContext::TemplateInstantiation:
       return "TemplateInstantiation";
@@ -462,10 +461,8 @@ private:
       return "TypeAliasTemplateInstantiation";
     case CodeSynthesisContext::PartialOrderingTTP:
       return "PartialOrderingTTP";
-    case CodeSynthesisContext::CheckTemplateParameter:
-      return std::nullopt;
     }
-    return std::nullopt;
+    return "";
   }
 
   template <bool BeginInstantiation>
@@ -473,14 +470,12 @@ private:
                                     const CodeSynthesisContext &Inst) {
     std::string YAML;
     {
-      std::optional<TemplightEntry> Entry =
-          getTemplightEntry<BeginInstantiation>(TheSema, Inst);
-      if (!Entry)
-        return;
       llvm::raw_string_ostream OS(YAML);
       llvm::yaml::Output YO(OS);
+      TemplightEntry Entry =
+          getTemplightEntry<BeginInstantiation>(TheSema, Inst);
       llvm::yaml::EmptyContext Context;
-      llvm::yaml::yamlize(YO, *Entry, true, Context);
+      llvm::yaml::yamlize(YO, Entry, true, Context);
     }
     Out << "---" << YAML << "\n";
   }
@@ -560,13 +555,10 @@ private:
   }
 
   template <bool BeginInstantiation>
-  static std::optional<TemplightEntry>
-  getTemplightEntry(const Sema &TheSema, const CodeSynthesisContext &Inst) {
+  static TemplightEntry getTemplightEntry(const Sema &TheSema,
+                                          const CodeSynthesisContext &Inst) {
     TemplightEntry Entry;
-    std::optional<std::string> Kind = toString(Inst.Kind);
-    if (!Kind)
-      return std::nullopt;
-    Entry.Kind = *Kind;
+    Entry.Kind = toString(Inst.Kind);
     Entry.Event = BeginInstantiation ? "Begin" : "End";
     llvm::raw_string_ostream OS(Entry.Name);
     printEntryName(TheSema, Inst.Entity, OS);