Compiler crashes when return statement is placed in onCreate method.

[JayThomason]

In the onCreate method for endpoint objects the compiler crashes during type-checking if the programmer attempts to return a value. The compiler does output a correct error message, yet it promptly crashes with a large stack trace, potentially obscuring the error message.

Example Waldo code (in file bug.wld):

Bug
Endpoint SingleSide;

SingleSide
{
    onCreate()
    {
        return 42;
    }
}

Full output from terminal:

---

Error.  onCreate expects to return 0 arguments.  Instead, you returned 1
arguments.

---

Line numbers:
8
None

---

Program text:
5   {
6       onCreate()
7       {
8\*          return 42;
9       }
10  }
11
Traceback (most recent call last):
  File "/Users/jay/Development/Waldo/bin/wcompile.py", line 369, in <module>
    printOutputArg,typeCheckArg,emitArg,versionNum,suppress_warnings)
  File "/Users/jay/Development/Waldo/bin/wcompile.py", line 201, in handleArgs
    astRootNode.typeCheck(fileText)
  File "/Users/jay/Development/Waldo/bin/../waldo/parser/ast/astNode.py", line 103, in typeCheck
    return typeChecker.typeCheck(self,progText,typeStack);
  File "/Users/jay/Development/Waldo/bin/../waldo/parser/ast/typeCheck/typeCheck.py", line 114, in typeCheck
    endpoint1Node.typeCheck(progText,typeStack,avoidFunctionObjects);
  File "/Users/jay/Development/Waldo/bin/../waldo/parser/ast/astNode.py", line 103, in typeCheck
    return typeChecker.typeCheck(self,progText,typeStack);
  File "/Users/jay/Development/Waldo/bin/../waldo/parser/ast/typeCheck/typeCheck.py", line 1958, in typeCheck
    endpointBodySection.typeCheck(progText,typeStack,avoidFunctionObjects);
  File "/Users/jay/Development/Waldo/bin/../waldo/parser/ast/astNode.py", line 103, in typeCheck
    return typeChecker.typeCheck(self,progText,typeStack);
  File "/Users/jay/Development/Waldo/bin/../waldo/parser/ast/typeCheck/typeCheck.py", line 1967, in typeCheck
    node.children[1].typeCheck(progText,typeStack,avoidFunctionObjects);
  File "/Users/jay/Development/Waldo/bin/../waldo/parser/ast/astNode.py", line 103, in typeCheck
    return typeChecker.typeCheck(self,progText,typeStack);
  File "/Users/jay/Development/Waldo/bin/../waldo/parser/ast/typeCheck/typeCheck.py", line 2142, in typeCheck
    s.typeCheck(progText,typeStack,avoidFunctionObjects);
  File "/Users/jay/Development/Waldo/bin/../waldo/parser/ast/astNode.py", line 103, in typeCheck
    return typeChecker.typeCheck(self,progText,typeStack);
  File "/Users/jay/Development/Waldo/bin/../waldo/parser/ast/typeCheck/typeCheck.py", line 2204, in typeCheck
    node.children[funcBodyIndex].typeCheck(progText,typeStack,avoidFunctionObjects);
  File "/Users/jay/Development/Waldo/bin/../waldo/parser/ast/astNode.py", line 103, in typeCheck
    return typeChecker.typeCheck(self,progText,typeStack);
  File "/Users/jay/Development/Waldo/bin/../waldo/parser/ast/typeCheck/typeCheck.py", line 2211, in typeCheck
    s.typeCheck(progText,typeStack,avoidFunctionObjects);
  File "/Users/jay/Development/Waldo/bin/../waldo/parser/ast/astNode.py", line 103, in typeCheck
    return typeChecker.typeCheck(self,progText,typeStack);
  File "/Users/jay/Development/Waldo/bin/../waldo/parser/ast/typeCheck/typeCheck.py", line 2262, in typeCheck
    s.typeCheck(progText,typeStack,avoidFunctionObjects);
  File "/Users/jay/Development/Waldo/bin/../waldo/parser/ast/astNode.py", line 103, in typeCheck
    return typeChecker.typeCheck(self,progText,typeStack);
  File "/Users/jay/Development/Waldo/bin/../waldo/parser/ast/typeCheck/typeCheck.py", line 2095, in typeCheck
    typeCheckError.lineNos,progText)
  File "/Users/jay/Development/Waldo/bin/../waldo/parser/ast/typeCheck/typeCheckUtil.py", line 50, in errorFunction
    lowerLineNum = max(0,errorLine - ERROR_NUM_LINES_EITHER_SIDE);
TypeError: unsupported operand type(s) for -: 'NoneType' and 'int' ```