[clang] [clang-tools-extra] [llvm] [clang] WIP: Improved Context Declaration tracking (PR #107942)

[Younan Zhang via cfe-commits]

================
@@ -15257,6 +15264,13 @@ Sema::ActOnStartOfFunctionDef(Scope *FnBodyScope, Declarator &D,
 
   D.setFunctionDefinitionKind(FunctionDefinitionKind::Definition);
   Decl *DP = HandleDeclarator(ParentScope, D, TemplateParameterLists);
+  if (auto *D = DP) {
+    if (auto *TD = dyn_cast<FunctionTemplateDecl>(D))
+      D = TD->getTemplatedDecl();
+    else
+      assert(isa<FunctionDecl>(D));
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zyn0217 wrote:

Maybe
```cpp
assert((isa<FunctionDecl, FunctionTemplateDecl>(D)));
if (auto *FTD = dyn_cast<>)
  ...
```
?

https://github.com/llvm/llvm-project/pull/107942