commit fb6deeb984d6d1dd16938c41a662bdafc969b745
author Aaron Ballman <aaron@aaronballman.com> Fri Jan 04 16:58:14 2019 +0000
committer Aaron Ballman <aaron@aaronballman.com> Fri Jan 04 16:58:14 2019 +0000
tree b22b6b1562daaf1890eadb5f41f633f578bc0f0b
parent c2054144eec0d6ee9826a3ba7439bab219872c84

Refactor the way we handle diagnosing unused expression results.

Rather than sprinkle calls to DiagnoseUnusedExprResult() around in places where we want diagnostics, we now diagnose unused expression statements and full expressions in a more generic way when acting on the final expression statement. This results in more appropriate diagnostics for [[nodiscard]] where we were previously lacking them, such as when the body of a for loop is not a compound statement.

This patch fixes PR39837.

llvm-svn: 350404

clang/lib/Parse/ParseOpenMP.cpp

diff --git a/clang/lib/Parse/ParseOpenMP.cpp b/clang/lib/Parse/ParseOpenMP.cpp
index 17c3fa3..dd2a8aa 100644
--- a/clang/lib/Parse/ParseOpenMP.cpp
+++ b/clang/lib/Parse/ParseOpenMP.cpp
@@ -314,7 +314,7 @@
     Actions.ActOnOpenMPDeclareReductionCombinerStart(getCurScope(), D);
     ExprResult CombinerResult =
         Actions.ActOnFinishFullExpr(ParseAssignmentExpression().get(),
-                                    D->getLocation(), /*DiscardedValue=*/true);
+                                    D->getLocation(), /*DiscardedValue*/ false);
     Actions.ActOnOpenMPDeclareReductionCombinerEnd(D, CombinerResult.get());
 
     if (CombinerResult.isInvalid() && Tok.isNot(tok::r_paren) &&
@@ -356,7 +356,7 @@
           if (Actions.getLangOpts().CPlusPlus) {
             InitializerResult = Actions.ActOnFinishFullExpr(
                 ParseAssignmentExpression().get(), D->getLocation(),
-                /*DiscardedValue=*/true);
+                /*DiscardedValue*/ false);
           } else {
             ConsumeToken();
             ParseOpenMPReductionInitializerForDecl(OmpPrivParm);
@@ -364,7 +364,7 @@
         } else {
           InitializerResult = Actions.ActOnFinishFullExpr(
               ParseAssignmentExpression().get(), D->getLocation(),
-              /*DiscardedValue=*/true);
+              /*DiscardedValue*/ false);
         }
         Actions.ActOnOpenMPDeclareReductionInitializerEnd(
             D, InitializerResult.get(), OmpPrivParm);
@@ -1455,7 +1455,7 @@
   ExprResult LHS(ParseCastExpression(
       /*isUnaryExpression=*/false, /*isAddressOfOperand=*/false, NotTypeCast));
   ExprResult Val(ParseRHSOfBinaryExpression(LHS, prec::Conditional));
-  Val = Actions.ActOnFinishFullExpr(Val.get(), ELoc);
+  Val = Actions.ActOnFinishFullExpr(Val.get(), ELoc, /*DiscardedValue*/ false);
 
   // Parse ')'.
   RLoc = Tok.getLocation();
@@ -1711,7 +1711,8 @@
     SourceLocation ELoc = Tok.getLocation();
     ExprResult LHS(ParseCastExpression(false, false, NotTypeCast));
     Val = ParseRHSOfBinaryExpression(LHS, prec::Conditional);
-    Val = Actions.ActOnFinishFullExpr(Val.get(), ELoc);
+    Val =
+        Actions.ActOnFinishFullExpr(Val.get(), ELoc, /*DiscardedValue*/ false);
   }
 
   // Parse ')'.
@@ -1996,7 +1997,8 @@
     Data.ColonLoc = Tok.getLocation();
     SourceLocation ELoc = ConsumeToken();
     ExprResult Tail = ParseAssignmentExpression();
-    Tail = Actions.ActOnFinishFullExpr(Tail.get(), ELoc);
+    Tail =
+        Actions.ActOnFinishFullExpr(Tail.get(), ELoc, /*DiscardedValue*/ false);
     if (Tail.isUsable())
       Data.TailExpr = Tail.get();
     else