---input---
// This should not be recognized as a function declaration followed by
// garbage.
string xyz(");");

// This should not be recognized as a function definition.

string xyz("){ }");

---tokens---
'// This should not be recognized as a function declaration followed by\n' Comment.Single

'// garbage.\n' Comment.Single

'string'      Name
' '           Text.Whitespace
'xyz'         Name
'('           Punctuation
'"'           Literal.String
');'          Literal.String
'"'           Literal.String
')'           Punctuation
';'           Punctuation
'\n'          Text.Whitespace

'\n'          Text.Whitespace

'// This should not be recognized as a function definition.\n' Comment.Single

'\n'          Text.Whitespace

'string'      Name
' '           Text.Whitespace
'xyz'         Name
'('           Punctuation
'"'           Literal.String
'){ }'        Literal.String
'"'           Literal.String
')'           Punctuation
';'           Punctuation
'\n'          Text.Whitespace