Ghost to Pure promotion doesn't seem to work with conditionals

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Description

module Test

assume val f : int -> GTot bool

let works (unit) : Tot int = 
  let _ = 
     let y = f 0 in 
     assert (y ==> 0=0);
     assert (not y ==> 1=1) in
  0

let fails (unit) : Tot int = 
  let _ = 
     let y = f 0 in 
     if y
     then assert (0=0)
     else assert (1=1) in
  0

Contributor guide

Research direction

Investigate the promotion from Ghost to Pure in the F* type checker when conditional expressions (if then else) are used. The failing test shows that direct assert works but if else fails, suggesting that the effect promotion logic may not handle conditionals correctly. Look into the type checking of 'if' expressions in the F* source code, focusing on how effects are computed and promoted.

Tech stack

None

Domain

compilers

Issue type

Bug

DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.

3

Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.

Half day

Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.

Active

ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.

Clear

Prerequisites

F* programmingproof assistant concepts

Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.

30