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Q97 / 100
What is the principal types property in type inference?
Correct! Well done.
Incorrect.
The correct answer is B) A type system has the principal types property if every typeable expression has a most general type that is an instance of every other type the expression can be given
B
Correct Answer
A type system has the principal types property if every typeable expression has a most general type that is an instance of every other type the expression can be given
Explanation
Hindley-Milner has principal types: the inferred type is the most general — any other valid type is a substitution instance of it. System F lacks principal types (type inference is undecidable). Principal types ensure type inference is well-defined.
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