[clang-tools-extra] [clang-tidy] Add fix-its to `avoid-return-with-void-value` check (PR #81420)

[Congcong Cai via cfe-commits]

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@@ -42,10 +43,28 @@ void AvoidReturnWithVoidValueCheck::check(
   const auto *VoidReturn = Result.Nodes.getNodeAs<ReturnStmt>("void_return");
   if (IgnoreMacros && VoidReturn->getBeginLoc().isMacroID())
     return;
-  if (!StrictMode && !Result.Nodes.getNodeAs<CompoundStmt>("compound_parent"))
+  const auto *SurroundingBlock =
+      Result.Nodes.getNodeAs<CompoundStmt>("compound_parent");
+  if (!StrictMode && !SurroundingBlock)
     return;
+  const StringRef ReturnExpr =
+      Lexer::getSourceText(CharSourceRange::getTokenRange(
+                               VoidReturn->getRetValue()->getSourceRange()),
+                           *Result.SourceManager, getLangOpts());
+  SourceLocation SemicolonPos;
+  if (const std::optional<Token> NextToken =
+          Lexer::findNextToken(VoidReturn->getRetValue()->getEndLoc(),
+                               *Result.SourceManager, getLangOpts()))
+    SemicolonPos = NextToken->getEndLoc();
+  std::string Replacement = (ReturnExpr + "; return;").str();
+  if (!SurroundingBlock)
+    Replacement = "{" + Replacement + "}";
   diag(VoidReturn->getBeginLoc(), "return statement within a void function "
-                                  "should not have a specified return value");
+                                  "should not have a specified return value")
+      << FixItHint::CreateReplacement(
+             CharSourceRange::getTokenRange(VoidReturn->getBeginLoc(),
+                                            SemicolonPos),
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HerrCai0907 wrote:

what will happen if `SemicolonPos` is invalid?

https://github.com/llvm/llvm-project/pull/81420