Point at all constraints before args

3 files changed, 86 insertions, 54 deletions

diff --git a/src/librustc_ast_passes/ast_validation.rs b/src/librustc_ast_passes/ast_validation.rs
index de7ae10723f..680a58d8b77 100644
--- a/src/librustc_ast_passes/ast_validation.rs
+++ b/src/librustc_ast_passes/ast_validation.rs
@@ -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;
@@ -647,24 +647,38 @@ 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 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")
             .emit();
     }
 }
diff --git a/src/test/ui/parser/issue-32214.stderr b/src/test/ui/parser/issue-32214.stderr
index 742f4fdc38b..6bb1425ee13 100644
--- a/src/test/ui/parser/issue-32214.stderr
+++ b/src/test/ui/parser/issue-32214.stderr
@@ -4,7 +4,7 @@ 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
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/suggestions/suggest-move-types.stderr b/src/test/ui/suggestions/suggest-move-types.stderr
index 4dd0613757a..b4cf0deacee 100644
--- a/src/test/ui/suggestions/suggest-move-types.stderr
+++ b/src/test/ui/suggestions/suggest-move-types.stderr
@@ -4,7 +4,7 @@ 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
 
 error: generic arguments must come before the first constraint
   --> $DIR/suggest-move-types.rs:33:43
@@ -13,70 +13,88 @@ 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
 
 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
 
 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
 
 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
 
 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
 
 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
 
 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
 
 error[E0747]: type provided when a lifetime was expected
   --> $DIR/suggest-move-types.rs:33:43