3f0acbbb48
This PR fixes how we determine whether a function parameter is an
instance.
Previously, we relied on binder annotations (e.g., `[Ring A]` vs `{_ :
Ring A}`)
to make this determination. This is unreliable because users
legitimately use
`{..}` binders for class types when the instance is already available
from
context. For example:
```lean
structure OrdSet (α : Type) [Hashable α] [BEq α] where
...
def OrdSet.insert {_ : Hashable α} {_ : BEq α} (s : OrdSet α) (a : α) : OrdSet α :=
...
```
Here, `Hashable` and `BEq` are classes, but the `{..}` binder is
intentional, the
instances come from `OrdSet`'s parameters, so type class resolution is
unnecessary.
The fix checks the parameter's *type* using `isClass?` rather than its
syntax, and
caches this information in `FunInfo`. This affects several subsystems:
- **Discrimination trees**: instance parameters should not be indexed
even if marked with `{..}`
- **Congruence lemma generation**: instances require special treatment
- **`grind` canonicalizer**: must ensure canonical instances
**Potential regressions**: automation may now behave differently in
cases where it
previously misidentified instance parameters. For example, a rewrite
rule in `simp` that was
not firing due to incorrect indexing may now fire.
---------
Co-authored-by: Kim Morrison <kim@tqft.net>
Co-authored-by: Claude <noreply@anthropic.com>
128 lines
4.4 KiB
Text
128 lines
4.4 KiB
Text
import Std.Data.HashMap
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set_option warn.sorry false
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macro_rules | `(tactic| get_elem_tactic_extensible) => `(tactic| grind)
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open Std
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structure IndexMap (α : Type u) (β : Type v) [BEq α] [Hashable α] where
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private indices : HashMap α Nat
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private keys : Array α
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private values : Array β
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private size_keys' : keys.size = values.size := by grind
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private WF : ∀ (i : Nat) (a : α), keys[i]? = some a ↔ indices[a]? = some i := by grind
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namespace IndexMap
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variable {α : Type u} {β : Type v} [BEq α] [Hashable α]
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variable {m : IndexMap α β} {a : α} {b : β} {i : Nat}
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@[inline] def size (m : IndexMap α β) : Nat :=
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m.values.size
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@[local grind =] private theorem size_keys : m.keys.size = m.size := m.size_keys'
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def emptyWithCapacity (capacity := 8) : IndexMap α β where
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indices := HashMap.emptyWithCapacity capacity
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keys := Array.emptyWithCapacity capacity
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values := Array.emptyWithCapacity capacity
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instance : EmptyCollection (IndexMap α β) where
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emptyCollection := emptyWithCapacity
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instance : Inhabited (IndexMap α β) where
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default := ∅
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@[inline] def contains (m : IndexMap α β)
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(a : α) : Bool :=
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m.indices.contains a
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instance : Membership α (IndexMap α β) where
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mem m a := a ∈ m.indices
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instance {m : IndexMap α β} {a : α} : Decidable (a ∈ m) :=
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inferInstanceAs (Decidable (a ∈ m.indices))
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@[local grind =] private theorem mem_indices_of_mem {m : IndexMap α β} {a : α} :
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a ∈ m ↔ a ∈ m.indices := Iff.rfl
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@[inline] def findIdx? (m : IndexMap α β) (a : α) : Option Nat := m.indices[a]?
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@[inline] def findIdx (m : IndexMap α β) (a : α) (h : a ∈ m := by get_elem_tactic) : Nat := m.indices[a]
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@[inline] def getIdx? (m : IndexMap α β) (i : Nat) : Option β := m.values[i]?
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@[inline] def getIdx (m : IndexMap α β) (i : Nat) (h : i < m.size := by get_elem_tactic) : β :=
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m.values[i]
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variable [LawfulBEq α] [LawfulHashable α]
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attribute [local grind _=_] IndexMap.WF
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private theorem getElem_indices_lt {h : a ∈ m} : m.indices[a] < m.size := by
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have : m.indices[a]? = some m.indices[a] := by grind
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grind
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grind_pattern getElem_indices_lt => m.indices[a]
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attribute [local grind] size
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instance : GetElem? (IndexMap α β) α β (fun m a => a ∈ m) where
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getElem m a h := m.values[m.indices[a]'h]
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getElem? m a := m.indices[a]?.bind (fun i => (m.values[i]?))
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getElem! m a := m.indices[a]?.bind (fun i => (m.values[i]?)) |>.getD default
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@[local grind =] private theorem getElem_def (m : IndexMap α β) (a : α) (h : a ∈ m) : m[a] = m.values[m.indices[a]'h] := rfl
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@[local grind =] private theorem getElem?_def (m : IndexMap α β) (a : α) :
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m[a]? = m.indices[a]?.bind (fun i => (m.values[i]?)) := rfl
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@[local grind =] private theorem getElem!_def [Inhabited β] (m : IndexMap α β) (a : α) :
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m[a]! = (m.indices[a]?.bind (fun i => (m.values[i]?))).getD default := rfl
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instance : LawfulGetElem (IndexMap α β) α β (fun m a => a ∈ m) where
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getElem?_def := by grind
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getElem!_def := by grind
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@[inline] def insert [LawfulBEq α] (m : IndexMap α β) (a : α) (b : β) :
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IndexMap α β :=
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match h : m.indices[a]? with
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| some i =>
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{ indices := m.indices
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keys := m.keys.set i a
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values := m.values.set i b }
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| none =>
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{ indices := m.indices.insert a m.size
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keys := m.keys.push a
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values := m.values.push b }
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/-! ### Verification theorems -/
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attribute [local grind] getIdx findIdx insert
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example (m : IndexMap α β) (a a' : α) (b : β) (h : a' ∈ m.insert a b) :
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(m.insert a b)[a'] = if h' : a' == a then b else m[a'] := by
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grind -ring -linarith -lia =>
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instantiate only [= getElem_def, insert]
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cases #dbaf
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next =>
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cases #54dd
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next => sorry
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next =>
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instantiate only
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instantiate only [= HashMap.getElem_insert]
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instantiate only [= size]
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instantiate only [= Array.getElem_push, = mem_indices_of_mem]
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next => sorry
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example (m : IndexMap α β) (a a' : α) (b : β) (h : a' ∈ m.insert a b) :
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(m.insert a b)[a'] = if h' : a' == a then b else m[a'] := by
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grind -ring -linarith -lia =>
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instantiate only [= getElem_def, insert]
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cases #dbaf
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next =>
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cases #54dd
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next => sorry
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next =>
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instantiate only
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instantiate only [= HashMap.getElem_insert]
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instantiate only [= size]
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instantiate only [= mem_indices_of_mem, = Array.getElem_push]
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next => sorry
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