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type_vars                                                       (Type)
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type_vars : hol_type -> hol_type list

SYNOPSIS
Returns the set of type variables in a type.

KEYWORDS
variable, type.

DESCRIBE
An invocation {type_vars ty} returns a list representing the set of
type variables occurring in {ty}.

FAILURE
Never fails.

EXAMPLE

- type_vars ((alpha --> beta) --> bool --> beta);
> val it = [`:'a`, `:'b`] : hol_type list




COMMENTS
Code should not depend on how elements are arranged in the
result of {type_vars}.

SEEALSO
Type.type_varsl, Type.type_var_in, Type.exists_tyvar,
Type.polymorphic, Term.free_vars.

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