[clang] Control analysis-based diagnostics with #pragma (PR #136323)

[Shafik Yaghmour via cfe-commits]

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@@ -16597,7 +16597,8 @@ ExprResult Sema::ActOnBlockStmtExpr(SourceLocation CaretLoc,
   BD->setCaptures(Context, Captures, BSI->CXXThisCaptureIndex != 0);
 
   // Pop the block scope now but keep it alive to the end of this function.
-  AnalysisBasedWarnings::Policy WP = AnalysisWarnings.getDefaultPolicy();
+  AnalysisBasedWarnings::Policy WP =
+      AnalysisWarnings.getPolicyInEffectAt(Body->getEndLoc());
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shafik wrote:

Static analysis points out that `Body` is nullptr checked above and so we should not be unconditionally dereferencing it here. 

https://github.com/llvm/llvm-project/pull/136323