diff --git a/libsolutil/StringUtils.h b/libsolutil/StringUtils.h
index 7a48c296f..d0f0ad988 100644
--- a/libsolutil/StringUtils.h
+++ b/libsolutil/StringUtils.h
@@ -231,7 +231,7 @@ inline std::string toLower(std::string _s)
 /// @return true if _c is a decimal digit character, false otherwise
 inline bool isDigit(char _c)
 {
-	return isdigit(_c, std::locale::classic());
+	return '0' <= _c && _c <= '9';
 }
 
 // Checks if character is printable using classic "C" locale
diff --git a/tools/solsmt.cpp b/tools/solsmt.cpp
index 4daccb9b5..5415b5e8e 100644
--- a/tools/solsmt.cpp
+++ b/tools/solsmt.cpp
@@ -70,7 +70,7 @@ public:
 			}
 			if (token() == ')')
 				advance();
-			return {subExpressions};
+			return {move(subExpressions)};
 		}
 		else
 			return {parseToken()};