diff -up webkitgtk-2.20.3/Source/JavaScriptCore/runtime/CodeCache.cpp.covscan_uninit webkitgtk-2.20.3/Source/JavaScriptCore/runtime/CodeCache.cpp
--- webkitgtk-2.20.3/Source/JavaScriptCore/runtime/CodeCache.cpp.covscan_uninit	2018-06-18 10:03:23.060605715 +0200
+++ webkitgtk-2.20.3/Source/JavaScriptCore/runtime/CodeCache.cpp	2018-06-18 10:03:44.223529644 +0200
@@ -129,7 +129,7 @@ UnlinkedFunctionExecutable* CodeCache::g
     // This function assumes an input string that would result in a single function declaration.
     StatementNode* statement = program->singleStatement();
     if (UNLIKELY(!statement)) {
-        JSToken token;
+        JSToken token = { };
         error = ParserError(ParserError::SyntaxError, ParserError::SyntaxErrorIrrecoverable, token, "Parser error", -1);
         return nullptr;
     }
@@ -137,7 +137,7 @@ UnlinkedFunctionExecutable* CodeCache::g
 
     StatementNode* funcDecl = static_cast<BlockNode*>(statement)->singleStatement();
     if (UNLIKELY(!funcDecl)) {
-        JSToken token;
+        JSToken token = { };
         error = ParserError(ParserError::SyntaxError, ParserError::SyntaxErrorIrrecoverable, token, "Parser error", -1);
         return nullptr;
     }