1726a61e88
This PR adds a failing test for `grind`, reported by @eric-wieser.
```
example {x : BitVec 2} : x - 2 • x + x = 0 := by
grind -- fails
```
There are several independent problems here!
1. Cutsat doesn't evaluate `2 ^ 2`:
```
-- [cutsat] Assignment satisfying linear constraints
-- [assign] 「2 ^ 2」 := 0
```
2. We don't normalize `3 * 2 • x` to `6 * x` in the ring solver:
```
-- [ring] Rings ▼
-- [] Ring `BitVec 2` ▼
-- [diseqs] Disequalities ▼
-- [_] ¬2 * x + 3 * 2 • x = 0
```
This should then give a contradiction because the characteristic of
`BitVec 2` is 4.
3. In `Int`, we're not normalizing `*` and `•`:
```
-- [ring] Rings ▼
-- [] Ring `Int` ▼
-- [basis] Basis ▼
-- [_] 2 * ↑x + -1 * ↑(2 • x) + -4 * ((2 * ↑x + -1 * ↑(2 • x)) / 4) + -1 * ((2 * ↑x + -1 * ↑(2 • x)) % 4) = 0
```
24 lines
845 B
Text
24 lines
845 B
Text
example {x : BitVec 2} : x - 2 * x + x = 0 := by
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grind -- succeeds
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example {x : BitVec 2} : x - 2 • x + x = 0 := by
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grind -- fails
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-- There are several independent problems here!
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-- 1. Cutsat doesn't evaluate `2 ^ 2`:
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-- [cutsat] Assignment satisfying linear constraints
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-- [assign] 「2 ^ 2」 := 0
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-- 2. We don't normalize `3 * 2 • x` to `6 * x` in the ring solver:
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-- [ring] Rings ▼
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-- [] Ring `BitVec 2` ▼
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-- [diseqs] Disequalities ▼
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-- [_] ¬2 * x + 3 * 2 • x = 0
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-- This should then give a contradiction because the characteristic of `BitVec 2` is 4.
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-- 3. In `Int`, we're not normalizing `*` and `•`:
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-- [ring] Rings ▼
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-- [] Ring `Int` ▼
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-- [basis] Basis ▼
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-- [_] 2 * ↑x + -1 * ↑(2 • x) + -4 * ((2 * ↑x + -1 * ↑(2 • x)) / 4) + -1 * ((2 * ↑x + -1 * ↑(2 • x)) % 4) = 0
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