Change a warning to an error.  Previously, we had only warned if a function specified its return type but did not return a value along one of its control flow paths.  This will cause unpredictable behavior when return temps do not initialize themselves by default (relying on other assignments to initialize). Now, the behavior will be deterministic and will correctly not allow the program to execute.
Change a warning to an error.  Previously, we had only warned if a function
specified its return type but did not return a value along one of its control
flow paths.  This will cause unpredictable behavior when return temps do not
initialize themselves by default (relying on other assignments to initialize).
Now, the behavior will be deterministic and will correctly not allow the
program to execute.

hildeth/chapel,chizarlicious/chapel,CoryMcCartan/chapel,hildeth/chapel,CoryMcCartan/chapel,sungeunchoi/chapel,chizarlicious/chapel,sungeunchoi/chapel,sungeunchoi/chapel,chizarlicious/chapel,sungeunchoi/chapel,CoryMcCartan/chapel,CoryMcCartan/chapel,hildeth/chapel,CoryMcCartan/chapel,hildeth/chapel,CoryMcCartan/chapel,chizarlicious/chapel,sungeunchoi/chapel,sungeunchoi/chapel,CoryMcCartan/chapel,hildeth/chapel,chizarlicious/chapel,hildeth/chapel,chizarlicious/chapel,sungeunchoi/chapel,chizarlicious/chapel,hildeth/chapel,sungeunchoi/chapel