Handle array to pointer decay for libc members (#176)

Author: lucic71

cpp2rust/converter/converter.cpp

@@ -1979,9 +1979,18 @@ bool Converter::VisitImplicitCastExpr(clang::ImplicitCastExpr *expr) {
       Convert(sub_expr);
       break;
     }
-    Convert(sub_expr);
     bool dest_pointee_const =
         expr->getType()->getPointeeType().isConstQualified();
+    if (const auto *member =
+            clang::dyn_cast<clang::MemberExpr>(sub_expr->IgnoreParenImpCasts());
+        member && IsCharArrayFieldFromLibc(member->getMemberDecl())) {
+      PushParen paren(*this);
+      Convert(sub_expr);
+      StrCat(dest_pointee_const ? ".as_ptr()" : ".as_mut_ptr()");
+      StrCat(keyword::kAs, dest_pointee_const ? "*const u8" : "*mut u8");
+      break;
+    }
+    Convert(sub_expr);
     if (clang::isa<clang::StringLiteral>(sub_expr) ||
         clang::isa<clang::PredefinedExpr>(sub_expr)) {
       StrCat(".as_ptr()");