Which of the following scenarios cannot be correctly implemented using only S-attributed definitions ?

Question

Which of the following scenarios  cannot  be correctly implemented using only  S-attributed definitions ?

Answer

Code generation for expressions where temporary variable labels must be propagated upwards.

Answer

Translation of declarations where scope information must be passed  from parent to children .

Answer

Type checking in a compiler where type of an expression is determined only from child attributes.

Answer

Constant folding where constant values are computed from leaf nodes upwards.

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