edcef51434
This PR refines several error error messages, mostly involving invalid
use of field notation, generalized field notation, and numeric
projection. Provides a new error explanation for field notation.
## Error message changes
In general:
- Uses a slightly different convention for expression-type pairs, where
the expression is always given `indentExpr` and the type is given
`inlineExpr` treatment. This is something of a workaround for the fact
that the `Format` type is awkward for embedding possibly-linebreaking
expressions in not-linebreaking text, which may be a separate issue
worth addressing.
- Tries to give slightly more "why" reasoning — the environment does not
contain `String.parse`, and _therefore you can't project `.parse` from a
`String`_.
Some specific examples:
### No such projection function
```lean4
#check "".parse
```
before:
```
error: Invalid field `parse`: The environment does not contain `String.parse`
""
has type
String
```
after:
```
error: Invalid field `parse`: The environment does not contain `String.parse`, so it is not possible to project the field `parse` from an expression
""
of type `String`
```
### Type does not have the correct form
```lean4
example (x : α) := (foo x).foo
```
before:
```
error: Invalid field notation: Type is not of the form `C ...` where C is a constant
foo x
has type
α
```
after:
```
error: Invalid field notation: Field projection operates on types of the form `C ...` where C is a constant. The expression
foo x
has type `α` which does not have the necessary form.
```
## Refactoring
Includes some refactoring changes as well:
- factors out multiple uses of number (1, 2, 3, 212, 222) to ordinal
("first", "second", "third", "212th", "222nd") conversion into
Lean.Elab.ErrorUtils
- significant refactoring of `resolveLValAux` in `Lean.Elab.App` — in
place of five helper functions, a special-case function case analysis,
and a case analysis on the projection type and structure, there's now a
single case analysis on the projection type and structure. This allows
several error messages to be more explicit (there were a number of cases
where index projection was being described as field projection in an
error messages) and gave the opportunity to slightly improve positining
for several errors: field *notation* errors should appear on `foo.bar`,
but field *projection* errors should appear only on the `bar` part of
`foo.bar`.
210 lines
5 KiB
Text
210 lines
5 KiB
Text
module
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prelude
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public import Module.Basic
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import Lean.DocString
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meta import Lean.Elab.Command
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/-! Definitions should be exported without their bodies by default -/
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/--
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info: def f : Nat :=
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<not imported>
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-/
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#guard_msgs in
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#print f
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/--
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error: Type mismatch
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rfl
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has type
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?m.5 = ?m.5
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but is expected to have type
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f = 1
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Note: The following definitions were not unfolded because their definition is not exposed:
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f ↦ 1
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-/
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#guard_msgs in
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example : f = 1 := rfl
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/--
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error: Tactic `apply` failed: could not unify the conclusion of `@rfl`
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?a = ?a
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with the goal
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f = 1
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Note: The full type of `@rfl` is
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∀ {α : Sort ?u.115} {a : α}, a = a
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Note: The following definitions were not unfolded because their definition is not exposed:
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f ↦ 1
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⊢ f = 1
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-/
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#guard_msgs in
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example : f = 1 := by apply rfl
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/-! Theorems should be exported without their bodies -/
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/--
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info: theorem t : f = 1 :=
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<not imported>
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-/
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#guard_msgs in
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#print t
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/--
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info: theorem trfl : f = 1 :=
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<not imported>
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-/
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#guard_msgs in
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#print trfl
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/-! Metadata of private decls should not be exported. -/
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-- Should not fail with 'unknown constant `inst*`
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/--
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error: failed to synthesize instance of type class
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X
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Hint: Type class instance resolution failures can be inspected with the `set_option trace.Meta.synthInstance true` command.
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-/
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#guard_msgs in
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def fX : X := inferInstance
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/-- error: `dsimp` made no progress -/
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#guard_msgs in
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example : P f := by dsimp only [t]; exact hP1
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example : P f := by simp only [t]; exact hP1
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/-- error: `dsimp` made no progress -/
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#guard_msgs in
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example : P f := by dsimp only [trfl]; exact hP1
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/-- error: `dsimp` made no progress -/
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#guard_msgs in
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example : P f := by dsimp only [trfl']; exact hP1
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example : P fexp := by dsimp only [fexp_trfl]; exact hP1
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example : P fexp := by dsimp only [fexp_trfl']; exact hP1
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example : t = t := by dsimp only [trfl]
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/--
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error: Invalid field `eq_def`: The environment does not contain `Nat.eq_def`, so it is not possible to project the field `eq_def` from an expression
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f
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of type `Nat`
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-/
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#guard_msgs in
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#check f.eq_def
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/--
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error: Invalid field `eq_unfold`: The environment does not contain `Nat.eq_unfold`, so it is not possible to project the field `eq_unfold` from an expression
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f
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of type `Nat`
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-/
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#guard_msgs in
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#check f.eq_unfold
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/-- error: Unknown constant `f_struct.eq_1` -/
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#guard_msgs in
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#check f_struct.eq_1
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/-- error: Unknown constant `f_struct.eq_def` -/
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#guard_msgs in
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#check f_struct.eq_def
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/-- error: Unknown constant `f_struct.eq_unfold` -/
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#guard_msgs in
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#check f_struct.eq_unfold
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/-- error: Unknown constant `f_wfrec.eq_1` -/
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#guard_msgs in
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#check f_wfrec.eq_1
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/-- error: Unknown constant `f_wfrec.eq_def` -/
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#guard_msgs in
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#check f_wfrec.eq_def
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/-- error: Unknown constant `f_wfrec.eq_unfold` -/
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#guard_msgs in
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#check f_wfrec.eq_unfold
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/-- error: Unknown constant `f_wfrec.induct_unfolding` -/
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#guard_msgs(pass trace, all) in
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#check f_wfrec.induct_unfolding
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/-- info: f_exp_wfrec.eq_1 (x✝ : Nat) : f_exp_wfrec 0 x✝ = x✝ -/
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#guard_msgs in
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#check f_exp_wfrec.eq_1
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/--
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info: f_exp_wfrec.eq_def (x✝ x✝¹ : Nat) :
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f_exp_wfrec x✝ x✝¹ =
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match x✝, x✝¹ with
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| 0, acc => acc
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| n.succ, acc => f_exp_wfrec n (acc + 1)
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-/
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#guard_msgs in
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#check f_exp_wfrec.eq_def
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/--
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info: f_exp_wfrec.eq_unfold :
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f_exp_wfrec = fun x x_1 =>
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match x, x_1 with
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| 0, acc => acc
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| n.succ, acc => f_exp_wfrec n (acc + 1)
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-/
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#guard_msgs in
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#check f_exp_wfrec.eq_unfold
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/--
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info: f_exp_wfrec.induct_unfolding (motive : Nat → Nat → Nat → Prop) (case1 : ∀ (acc : Nat), motive 0 acc acc)
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(case2 : ∀ (n acc : Nat), motive n (acc + 1) (f_exp_wfrec n (acc + 1)) → motive n.succ acc (f_exp_wfrec n (acc + 1)))
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(a✝ a✝¹ : Nat) : motive a✝ a✝¹ (f_exp_wfrec a✝ a✝¹)
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-/
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#guard_msgs(pass trace, all) in
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#check f_exp_wfrec.induct_unfolding
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/-! Basic non-`meta` check. -/
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/-- error: Invalid definition `nonMeta`, may not access declaration `pubMeta` marked as `meta` -/
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#guard_msgs in
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def nonMeta := pubMeta
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/-! `simp` should not pick up inaccessible definitional equations. -/
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/-- error: `simp` made no progress -/
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#guard_msgs in
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theorem f_struct_eq : f_struct 0 = 0 := by
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simp
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/-! `[inherit_doc]` should work independently of visibility. -/
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/-- info: some "A private definition. " -/
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#guard_msgs in
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open Lean in
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#eval show CoreM _ from do findDocString? (← getEnv) ``pubInheritDoc
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/-! Cross-module `meta` checks, including involving compiler-introduced constants. -/
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attribute [local delab Nat] delab
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/--
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error: Cannot add attribute `[Lean.PrettyPrinter.Delaborator.delabAttribute]`: Declaration `noMetaDelab` must be marked as `meta`
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-/
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#guard_msgs in
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attribute [local delab Nat] noMetaDelab
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@[noinline] meta def pap (f : α → β) (a : α) : β := f a
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public meta def delab' : Lean.PrettyPrinter.Delaborator.Delab :=
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pap delab
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-- Used to complain about `_boxed` not being meta
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attribute [local delab Nat] delab'
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/--
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error: Invalid `meta` definition `metaUsingNonMeta`, `f` is not accessible here; consider adding `public meta import Module.Basic`
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-/
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#guard_msgs in
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public meta def metaUsingNonMeta : Nat :=
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f
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