diff --git a/src/xmllang/parser.y b/src/xmllang/parser.y
index 17e0d360051..1027cb03dc7 100644
--- a/src/xmllang/parser.y
+++ b/src/xmllang/parser.y
@@ -24,6 +24,12 @@ int yyxmlerror(xml_parsert &xml_parser, void *scanner, const std::string &error)
 // unreachable code
 #pragma warning(disable:4702)
 #endif
+
+// Bison-generated yydestruct only handles symbols with %destructor;
+// suppress the warning about unhandled enum values in that switch.
+#if defined(__GNUC__) || defined(__clang__)
+#pragma GCC diagnostic ignored "-Wswitch-enum"
+#endif
 %}
 
 %parse-param {xml_parsert &xml_parser}
@@ -33,10 +39,13 @@ int yyxmlerror(xml_parsert &xml_parser, void *scanner, const std::string &error)
 %union {char *s;}
 
 %token STARTXMLDECL
-%token VERSION STARTPI ENDPI EQ SLASH CLOSE END
-%token <s> ENCODING NAME VALUE DATA COMMENT START
+%token VERSION ENDPI EQ SLASH CLOSE END
+%token <s> ENCODING NAME VALUE DATA COMMENT START STARTPI
 %type <s> name_opt
 
+// Memory management: ensure allocated string tokens are freed during error recovery
+%destructor { free($$); } ENCODING NAME VALUE DATA COMMENT START STARTPI name_opt
+
 %%
 
 document
@@ -68,7 +77,7 @@ misc
 
 PI
  : STARTPI NAME
-   { free($2); xml_parser.stack.push_back(&xml_parser.parse_tree.xml); }
+   { free($1); free($2); xml_parser.stack.push_back(&xml_parser.parse_tree.xml); }
    attribute_seq_opt
    { xml_parser.stack.pop_back(); }
    ENDPI