FunctionDecl exceptionHandler = resolveCall(functionDecl.exceptionHandler);
if (exceptionHandler == null)
addError("Cannot resolve exception handler: " + functionDecl.exceptionHandler,
functionDecl.sourceLine, functionDecl.sourceColumn);
else {
int argsSize = exceptionHandler.arguments().children().size();
// Verify exception handler template.
if (!exceptionHandler.patternMatching)
addError("Exception handler must be a pattern-matching function (did you mean '=>')",
exceptionHandler.sourceLine, exceptionHandler.sourceColumn);
else if (argsSize != 1) {