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`.
14 lines
881 B
Text
14 lines
881 B
Text
funind_errors.lean:4:7-4:26: error(lean.unknownIdentifier): Unknown identifier `doesNotExist.induct`
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funind_errors.lean:22:7-22:23: error(lean.unknownIdentifier): Unknown constant `takeWhile.induct`
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takeWhile.foo.induct.{u_1} {α : Type u_1} (p : α → Bool) (as : Array α) (motive : Nat → Array α → Prop)
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(case1 :
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∀ (i : Nat) (r : Array α) (h : i < as.size),
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have a := as[i];
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p a = true → motive (i + 1) (r.push a) → motive i r)
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(case2 :
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∀ (i : Nat) (r : Array α) (h : i < as.size),
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have a := as[i];
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¬p a = true → motive i r)
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(case3 : ∀ (i : Nat) (r : Array α), ¬i < as.size → motive i r) (i : Nat) (r : Array α) : motive i r
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funind_errors.lean:38:7-38:20: error(lean.unknownIdentifier): Unknown constant `idEven.induct`
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funind_errors.lean:45:7-45:19: error(lean.unknownIdentifier): Unknown constant `idAcc.induct`
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