[PATCH] D151383: Check for specific return types on all functions

[NagaChaitanya Vellanki via Phabricator via cfe-commits]

chaitanyav created this revision.
chaitanyav added a reviewer: royjacobson.
Herald added subscribers: PiotrZSL, carlosgalvezp.
Herald added a reviewer: njames93.
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chaitanyav requested review of this revision.
Herald added a project: clang-tools-extra.
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Extend the check to all functions with return types like

  std::error_code, std::expected, boost::system::error_code, abseil::Status...
  
  Resolves issue https://github.com/llvm/llvm-project/issues/62884


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D151383

Files:
  clang-tools-extra/clang-tidy/bugprone/UnusedReturnValueCheck.cpp


Index: clang-tools-extra/clang-tidy/bugprone/UnusedReturnValueCheck.cpp
===================================================================
--- clang-tools-extra/clang-tidy/bugprone/UnusedReturnValueCheck.cpp
+++ clang-tools-extra/clang-tidy/bugprone/UnusedReturnValueCheck.cpp
@@ -156,6 +156,15 @@
   auto UnusedInRangeForStmt = cxxForRangeStmt(hasBody(MatchedCallExpr));
   auto UnusedInCaseStmt = switchCase(forEach(MatchedCallExpr));
 
+  Finder->addMatcher(
+      callExpr(callee(functionDecl(anyOf(
+                   hasReturnTypeLoc(loc(asString("std::error_code"))),
+                   hasReturnTypeLoc(loc(asString("std::expected"))),
+                   hasReturnTypeLoc(loc(asString("boost::system::error_code"))),
+                   hasReturnTypeLoc(loc(asString("abseil::Status")))))))
+          .bind("return-types"),
+      this);
+
   Finder->addMatcher(
       stmt(anyOf(UnusedInCompoundStmt, UnusedInIfStmt, UnusedInWhileStmt,
                  UnusedInDoStmt, UnusedInForStmt, UnusedInRangeForStmt,
@@ -164,6 +173,16 @@
 }
 
 void UnusedReturnValueCheck::check(const MatchFinder::MatchResult &Result) {
+
+  if (const auto *Matched = Result.Nodes.getNodeAs<CallExpr>("return-types")) {
+    diag(Matched->getBeginLoc(),
+         "the value returned by this function should be used")
+        << Matched->getSourceRange();
+    diag(Matched->getBeginLoc(),
+         "cast the expression to void to silence this warning",
+         DiagnosticIDs::Note);
+  };
+
   if (const auto *Matched = Result.Nodes.getNodeAs<CallExpr>("match")) {
     diag(Matched->getBeginLoc(),
          "the value returned by this function should be used")


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