[clang] [lldb] [clang] implement CWG1980 and CWG2064: instantiation-dependency improvements (PR #190495)

[via cfe-commits]

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@@ -108,3 +108,22 @@ decltype([b = C(3)](){ return 4; }()) x;
 } // namespace cwg3156
 
 // cwg3172: na
+
+namespace cwg3179 { // cwg3179: 23 tentatively ready 2026-04-30
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h-vetinari wrote:

```suggestion
namespace cwg3179 { // cwg3179: 24 tentatively ready 2026-04-30
```

https://github.com/llvm/llvm-project/pull/190495