[clang] [clang] Implement P2582R1: CTAD from inherited constructors (PR #98788)

[Haojian Wu via cfe-commits]

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@@ -1388,6 +1695,33 @@ void Sema::DeclareImplicitDeductionGuides(TemplateDecl *Template,
   if (!AddedAny)
     Transform.buildSimpleDeductionGuide(std::nullopt);
 
+  // FIXME: Handle explicit deduction guides from inherited constructors
+  // when the base deduction guides are declared after this has first run
+  CXXRecordDecl *TemplatedDecl = Pattern->getTemplatedDecl();
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hokein wrote:

nit: can we move this chunk of code right after the statement on Line 1727?

https://github.com/llvm/llvm-project/pull/98788