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Tweak output of type params and constraints in the wrong order #70519

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Merged
merged 6 commits into from
Apr 6, 2020
Merged

Tweak output of type params and constraints in the wrong order #70519

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33d793c
Point at all constraints before args
estebank Mar 28, 2020
dcb4e81
Suggest correct order for args and constraints
estebank Mar 29, 2020
c2e0e71
Suggest correct order for arguments when encountering early constraints
estebank Mar 29, 2020
e84cb65
review comment: wording
estebank Mar 29, 2020
c9f55ea
review comments: use `partition_map`
estebank Apr 5, 2020
17a9523
Reduce the visual clutter
estebank Apr 6, 2020
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65 changes: 51 additions & 14 deletions src/librustc_ast_passes/ast_validation.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -14,7 +14,7 @@ use rustc_ast::visit::{self, AssocCtxt, FnCtxt, FnKind, Visitor};
use rustc_ast::walk_list;
use rustc_ast_pretty::pprust;
use rustc_data_structures::fx::FxHashMap;
use rustc_errors::{error_code, struct_span_err, Applicability};
use rustc_errors::{error_code, pluralize, struct_span_err, Applicability};
use rustc_parse::validate_attr;
use rustc_session::lint::builtin::PATTERNS_IN_FNS_WITHOUT_BODY;
use rustc_session::lint::LintBuffer;
Expand Down Expand Up @@ -647,24 +647,61 @@ impl<'a> AstValidator<'a> {
return;
}
// Find all generic argument coming after the first constraint...
let mut misplaced_args = Vec::new();
let mut first = None;
for arg in &data.args {
match (arg, first) {
(AngleBracketedArg::Arg(a), Some(_)) => misplaced_args.push(a.span()),
(AngleBracketedArg::Constraint(c), None) => first = Some(c.span),
(AngleBracketedArg::Arg(_), None) | (AngleBracketedArg::Constraint(_), Some(_)) => {
}
}
}
let constraint_spans = data
.args
.iter()
.filter_map(|arg| match arg {
AngleBracketedArg::Constraint(c) => Some(c.span),
_ => None,
})
.collect::<Vec<_>>();
let arg_spans = data
.args
.iter()
.filter_map(|arg| match arg {
AngleBracketedArg::Arg(a) => Some(a.span()),
_ => None,
})
.collect::<Vec<_>>();
let snippet_span = match &constraint_spans[..] {
[single] => *single,
[first, .., last] => first.to(*last),
[] => unreachable!(),
};
let removal_span = match &arg_spans[..] {
[first, ..] => snippet_span.until(*first),
[] => unreachable!(),
};
let sugg_span = match &arg_spans[..] {
[.., last] => last.shrink_to_hi(),
[] => unreachable!(),
};
let snippet = self.session.source_map().span_to_snippet(snippet_span).unwrap();
let constraint_len = constraint_spans.len();
// ...and then error:
self.err_handler()
.struct_span_err(
misplaced_args.clone(),
arg_spans.clone(),
"generic arguments must come before the first constraint",
)
.span_label(first.unwrap(), "the first constraint is provided here")
.span_labels(misplaced_args, "generic argument")
.span_labels(
constraint_spans,
&format!(
"the constraint{} {} provided here",
pluralize!(constraint_len),
if constraint_len == 1 { "is" } else { "are" }
),
)
.span_labels(arg_spans, "generic argument")
.multipart_suggestion(
"move the constraints after the generic arguments",
vec![
(removal_span, String::new()),
(sugg_span.shrink_to_lo(), ", ".to_string()),
(sugg_span, snippet),
],
Applicability::MachineApplicable,
)
.emit();
}
}
Expand Down
7 changes: 6 additions & 1 deletion src/test/ui/parser/issue-32214.stderr
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Original file line number Diff line number Diff line change
Expand Up @@ -4,7 +4,12 @@ error: generic arguments must come before the first constraint
LL | pub fn test<W, I: Trait<Item=(), W> >() {}
| ------- ^ generic argument
| |
| the first constraint is provided here
| the constraint is provided here
|
help: move the constraints after the generic arguments
|
LL | pub fn test<W, I: Trait<W, Item=()> >() {}
| --^^^^^^^

error: aborting due to previous error

136 changes: 97 additions & 39 deletions src/test/ui/suggestions/suggest-move-types.stderr
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Original file line number Diff line number Diff line change
Expand Up @@ -4,7 +4,12 @@ error: generic arguments must come before the first constraint
LL | struct A<T, M: One<A=(), T>> {
| ---- ^ generic argument
| |
| the first constraint is provided here
| the constraint is provided here
|
help: move the constraints after the generic arguments
|
LL | struct A<T, M: One<T, A=()>> {
| --^^^^

error: generic arguments must come before the first constraint
--> $DIR/suggest-move-types.rs:33:43
Expand All @@ -13,70 +18,123 @@ LL | struct Al<'a, T, M: OneWithLifetime<A=(), T, 'a>> {
| ---- ^ ^^ generic argument
| | |
| | generic argument
| the first constraint is provided here
| the constraint is provided here
|
help: move the constraints after the generic arguments
|
LL | struct Al<'a, T, M: OneWithLifetime<T, 'a, A=()>> {
| -- ^^^^

error: generic arguments must come before the first constraint
--> $DIR/suggest-move-types.rs:40:46
|
LL | struct B<T, U, V, M: Three<A=(), B=(), C=(), T, U, V>> {
| ---- ^ ^ ^ generic argument
| | | |
| | | generic argument
| | generic argument
| the first constraint is provided here
| ---- ---- ---- ^ ^ ^ generic argument
| | | | | |
| | | | | generic argument
| | | | generic argument
| | | the constraints are provided here
| | the constraints are provided here
| the constraints are provided here
|
help: move the constraints after the generic arguments
|
LL | struct B<T, U, V, M: Three<T, U, V, A=(), B=(), C=()>> {
| -- ^^^^^^^^^^^^^^^^

error: generic arguments must come before the first constraint
--> $DIR/suggest-move-types.rs:48:71
|
LL | struct Bl<'a, 'b, 'c, T, U, V, M: ThreeWithLifetime<A=(), B=(), C=(), T, U, V, 'a, 'b, 'c>> {
| ---- ^ ^ ^ ^^ ^^ ^^ generic argument
| | | | | | |
| | | | | | generic argument
| | | | | generic argument
| | | | generic argument
| | | generic argument
| | generic argument
| the first constraint is provided here
| ---- ---- ---- ^ ^ ^ ^^ ^^ ^^ generic argument
| | | | | | | | |
| | | | | | | | generic argument
| | | | | | | generic argument
| | | | | | generic argument
| | | | | generic argument
| | | | generic argument
| | | the constraints are provided here
| | the constraints are provided here
| the constraints are provided here
|
help: move the constraints after the generic arguments
|
LL | struct Bl<'a, 'b, 'c, T, U, V, M: ThreeWithLifetime<T, U, V, 'a, 'b, 'c, A=(), B=(), C=()>> {
| -- ^^^^^^^^^^^^^^^^

error: generic arguments must come before the first constraint
--> $DIR/suggest-move-types.rs:57:49
--> $DIR/suggest-move-types.rs:57:28
|
LL | struct C<T, U, V, M: Three<T, A=(), B=(), C=(), U, V>> {
| ---- ^ ^ generic argument
| | |
| | generic argument
| the first constraint is provided here
| ^ ---- ---- ---- ^ ^ generic argument
| | | | | |
| | | | | generic argument
| | | | the constraints are provided here
| | | the constraints are provided here
| | the constraints are provided here
| generic argument
|
help: move the constraints after the generic arguments
|
LL | struct C<T, U, V, M: Three<A=(), B=(), C=(), U, V, A=(), B=(), C=()>> {
| -- ^^^^^^^^^^^^^^^^

error: generic arguments must come before the first constraint
--> $DIR/suggest-move-types.rs:65:78
--> $DIR/suggest-move-types.rs:65:53
|
LL | struct Cl<'a, 'b, 'c, T, U, V, M: ThreeWithLifetime<T, 'a, A=(), B=(), C=(), U, 'b, V, 'c>> {
| ---- ^ ^^ ^ ^^ generic argument
| | | | |
| | | | generic argument
| | | generic argument
| | generic argument
| the first constraint is provided here
| ^ ^^ ---- ---- ---- ^ ^^ ^ ^^ generic argument
| | | | | | | | |
| | | | | | | | generic argument
| | | | | | | generic argument
| | | | | | generic argument
| | | | | the constraints are provided here
| | | | the constraints are provided here
| | | the constraints are provided here
| | generic argument
| generic argument
|
help: move the constraints after the generic arguments
|
LL | struct Cl<'a, 'b, 'c, T, U, V, M: ThreeWithLifetime<A=(), B=(), C=(), U, 'b, V, 'c, A=(), B=(), C=()>> {
| -- ^^^^^^^^^^^^^^^^

error: generic arguments must come before the first constraint
--> $DIR/suggest-move-types.rs:74:43
--> $DIR/suggest-move-types.rs:74:28
|
LL | struct D<T, U, V, M: Three<T, A=(), B=(), U, C=(), V>> {
| ---- ^ ^ generic argument
| | |
| | generic argument
| the first constraint is provided here
| ^ ---- ---- ^ ---- ^ generic argument
| | | | | |
| | | | | the constraints are provided here
| | | | generic argument
| | | the constraints are provided here
| | the constraints are provided here
| generic argument
|
help: move the constraints after the generic arguments
|
LL | struct D<T, U, V, M: Three<A=(), B=(), U, C=(), V, A=(), B=(), U, C=()>> {
| -- ^^^^^^^^^^^^^^^^^^^

error: generic arguments must come before the first constraint
--> $DIR/suggest-move-types.rs:82:72
--> $DIR/suggest-move-types.rs:82:53
|
LL | struct Dl<'a, 'b, 'c, T, U, V, M: ThreeWithLifetime<T, 'a, A=(), B=(), U, 'b, C=(), V, 'c>> {
| ---- ^ ^^ ^ ^^ generic argument
| | | | |
| | | | generic argument
| | | generic argument
| | generic argument
| the first constraint is provided here
| ^ ^^ ---- ---- ^ ^^ ---- ^ ^^ generic argument
| | | | | | | | |
| | | | | | | | generic argument
| | | | | | | the constraints are provided here
| | | | | | generic argument
| | | | | generic argument
| | | | the constraints are provided here
| | | the constraints are provided here
| | generic argument
| generic argument
|
help: move the constraints after the generic arguments
|
LL | struct Dl<'a, 'b, 'c, T, U, V, M: ThreeWithLifetime<A=(), B=(), U, 'b, C=(), V, 'c, A=(), B=(), U, 'b, C=()>> {
| -- ^^^^^^^^^^^^^^^^^^^^^^^

error[E0747]: type provided when a lifetime was expected
--> $DIR/suggest-move-types.rs:33:43
Expand Down