[clang] Add test for CWG1822

[[https://wg21.link/p1787 | P1787]]: CWG1822 is resolved by specifying that the body of a lambda remains in the surrounding (function parameter) scope.
Wording: A parameter-declaration-clause P introduces a function parameter scope that includes P. <...> If P is associated with a lambda-declarator, its scope extends to the end of the compound-statement in the lambda-expression. ([basic.scope.param])

Reviewed By: #clang-language-wg, shafik

Differential Revision: https://reviews.llvm.org/D147836

Author: Endilll

clang/test/CXX/drs/dr18xx.cpp

@@ -50,6 +50,15 @@ namespace dr1815 { // dr1815: no
 #endif
 }
 
+namespace dr1822 { // dr1822: yes
+#if __cplusplus >= 201103L
+  int a;
+  auto x = [] (int a) {
+#pragma clang __debug dump a // CHECK: ParmVarDecl
+  };
+#endif
+}
+
 namespace dr1872 { // dr1872: 9
 #if __cplusplus >= 201103L
   template<typename T> struct A : T {

clang/www/cxx_dr_status.html

@@ -10739,7 +10739,7 @@ <h2 id="cxxdr">C++ defect report implementation status</h2>
     <td><a href="https://wg21.link/cwg1822">1822</a></td>
     <td>CD6</td>
     <td>Lookup of parameter names in <I>lambda-expression</I>s</td>
-    <td class="none" align="center">Unknown</td>
+    <td class="full" align="center">Yes</td>
   </tr>
   <tr id="1823">
     <td><a href="https://wg21.link/cwg1823">1823</a></td>