Surface error for plain return statement in coroutine earlier (#100985)

When a plain return statement was used in a coroutine, the error "return
statement not allowed in coroutine" was surfaced too late (e.g. after
other errors in the return statement). Surfacing it earlier now, to make
the issue more obvious.

1 files changed, 10 insertions, 0 deletions

diff --git a/clang/lib/Sema/SemaStmt.cpp b/clang/lib/Sema/SemaStmt.cpp
index 34d2d39..d283eaa 100644
--- a/clang/lib/Sema/SemaStmt.cpp
+++ b/clang/lib/Sema/SemaStmt.cpp
@@ -3747,6 +3747,16 @@ Sema::ActOnReturnStmt(SourceLocation ReturnLoc, Expr *RetValExp,
         Diag(ReturnLoc, diag::err_acc_branch_in_out_compute_construct)
         << /*return*/ 1 << /*out of */ 0);
 
+  // using plain return in a coroutine is not allowed.
+  FunctionScopeInfo *FSI = getCurFunction();
+  if (FSI->FirstReturnLoc.isInvalid() && FSI->isCoroutine()) {
+    assert(FSI->FirstCoroutineStmtLoc.isValid() &&
+           "first coroutine location not set");
+    Diag(ReturnLoc, diag::err_return_in_coroutine);
+    Diag(FSI->FirstCoroutineStmtLoc, diag::note_declared_coroutine_here)
+        << FSI->getFirstCoroutineStmtKeyword();
+  }
+
   StmtResult R =
       BuildReturnStmt(ReturnLoc, RetVal.get(), /*AllowRecovery=*/true);
   if (R.isInvalid() || ExprEvalContexts.back().isDiscardedStatementContext())