Add a warning for implicit conversion from function literals (and static
methods) to bool. E.g.
void foo() {}
if (f) { ... // <- Warns here.
}
Only applies to non-weak functions, and does not apply if the function address
is taken explicitly with the addr-of operator.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@145849 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Sema/SemaChecking.cpp b/lib/Sema/SemaChecking.cpp
index 0d640a8..1ec7e39 100644
--- a/lib/Sema/SemaChecking.cpp
+++ b/lib/Sema/SemaChecking.cpp
@@ -3758,6 +3758,25 @@
// by a check in AnalyzeImplicitConversions().
return DiagnoseImpCast(S, E, T, CC,
diag::warn_impcast_string_literal_to_bool);
+ if (Source->isFunctionType()) {
+ // Warn on function to bool. Checks free functions and static member
+ // functions. Weakly imported functions are excluded from the check,
+ // since it's common to test their value to check whether the linker
+ // found a definition for them.
+ ValueDecl *D = 0;
+ if (DeclRefExpr* R = dyn_cast<DeclRefExpr>(E)) {
+ D = R->getDecl();
+ } else if (MemberExpr *M = dyn_cast<MemberExpr>(E)) {
+ D = M->getMemberDecl();
+ }
+
+ if (D && !D->isWeak()) {
+ FunctionDecl* F = cast<FunctionDecl>(D);
+ S.Diag(E->getExprLoc(), diag::warn_impcast_function_to_bool)
+ << F << E->getSourceRange() << SourceRange(CC);
+ return;
+ }
+ }
return; // Other casts to bool are not checked.
}