[clang-tools-extra] [clangd] Add config option to allow detection of unused system headers (PR #87208)

[kadir çetinkaya via cfe-commits]

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@@ -68,24 +68,32 @@ bool isIgnored(llvm::StringRef HeaderPath, HeaderFilter IgnoreHeaders) {
 }
 
 bool mayConsiderUnused(const Inclusion &Inc, ParsedAST &AST,
-                       const include_cleaner::PragmaIncludes *PI) {
+                       const include_cleaner::PragmaIncludes *PI,
+                       bool AnalyzeAngledIncludes) {
   assert(Inc.HeaderID);
   auto HID = static_cast<IncludeStructure::HeaderID>(*Inc.HeaderID);
   auto FE = AST.getSourceManager().getFileManager().getFileRef(
       AST.getIncludeStructure().getRealPath(HID));
   assert(FE);
   if (FE->getDir() == AST.getPreprocessor()
-                  .getHeaderSearchInfo()
-                  .getModuleMap()
-                  .getBuiltinDir()) 
+                          .getHeaderSearchInfo()
+                          .getModuleMap()
+                          .getBuiltinDir())
     return false;
   if (PI && PI->shouldKeep(*FE))
     return false;
   // FIXME(kirillbobyrev): We currently do not support the umbrella headers.
   // System headers are likely to be standard library headers.
-  // Until we have good support for umbrella headers, don't warn about them.
-  if (Inc.Written.front() == '<')
-    return tooling::stdlib::Header::named(Inc.Written).has_value();
+  // Until we have good support for umbrella headers, don't warn about them
+  // (unless analysis is explicitly enabled).
+  if (Inc.Written.front() == '<') {
+    if (tooling::stdlib::Header::named(Inc.Written)) {
+      return true;
+    }
+    if (!AnalyzeAngledIncludes) {
+      return false;
+    }
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kadircet wrote:

LLVM style prefers no braces for single line && statement blocks.

https://github.com/llvm/llvm-project/pull/87208