Broaden -Wstring-conversion to catch string literals in logical or expressions.
Previously, string literals were ignored in all logical expressions.  This
reduces it to only ignore in logical and expressions.

assert(0 && "error"); // No warning
assert(0 || "error"); // Warn

Fixes PR17565

llvm-svn: 200056
diff --git a/clang/lib/Sema/SemaChecking.cpp b/clang/lib/Sema/SemaChecking.cpp
index dca678d..472ae4d 100644
--- a/clang/lib/Sema/SemaChecking.cpp
+++ b/clang/lib/Sema/SemaChecking.cpp
@@ -5346,8 +5346,8 @@
   if (Target->isSpecificBuiltinType(BuiltinType::Bool)) {
     if (isa<StringLiteral>(E))
       // Warn on string literal to bool.  Checks for string literals in logical
-      // expressions, for instances, assert(0 && "error here"), are prevented
-      // by a check in AnalyzeImplicitConversions().
+      // and expressions, for instance, assert(0 && "error here"), are
+      // prevented by a check in AnalyzeImplicitConversions().
       return DiagnoseImpCast(S, E, T, CC,
                              diag::warn_impcast_string_literal_to_bool);
     if (Source->isFunctionType()) {
@@ -5698,15 +5698,16 @@
   // Now just recurse over the expression's children.
   CC = E->getExprLoc();
   BinaryOperator *BO = dyn_cast<BinaryOperator>(E);
-  bool IsLogicalOperator = BO && BO->isLogicalOp();
+  bool IsLogicalAndOperator = BO && BO->getOpcode() == BO_LAnd;
   for (Stmt::child_range I = E->children(); I; ++I) {
     Expr *ChildExpr = dyn_cast_or_null<Expr>(*I);
     if (!ChildExpr)
       continue;
 
-    if (IsLogicalOperator &&
+    if (IsLogicalAndOperator &&
         isa<StringLiteral>(ChildExpr->IgnoreParenImpCasts()))
-      // Ignore checking string literals that are in logical operators.
+      // Ignore checking string literals that are in logical and operators.
+      // This is a common pattern for asserts.
       continue;
     AnalyzeImplicitConversions(S, ChildExpr, CC);
   }