Add error for scratch slot load before store #47
Merged
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This PR makes the compiler throw an error if a scratch slot is loaded before anything has been stored in it. This should make it safer to use
ScratchVar
andMaybeValue
.In order to make this type of error indicate where in the program an improperly used slot is, I had to change a few things. I modified
TealComponent
and its subclasses to contain references to theExpr
that created them, and I used thetraceback
module to create formatted tracebacks every time anExpr
is created. These two changes allowed me to embed useful location information in the error that gets thrown.Closes #35.