Further tweak spans in ast validation errors

11 files changed, 91 insertions, 48 deletions

diff --git a/src/librustc_ast_passes/ast_validation.rs b/src/librustc_ast_passes/ast_validation.rs
index d90e9c4df26..eff58ad4d9a 100644
--- a/src/librustc_ast_passes/ast_validation.rs
+++ b/src/librustc_ast_passes/ast_validation.rs
@@ -13,7 +13,7 @@ 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;
@@ -887,30 +887,63 @@ impl<'a> Visitor<'a> for AstValidator<'a> {
                 if is_auto == IsAuto::Yes {
                     // Auto traits cannot have generics, super traits nor contain items.
                     if !generics.params.is_empty() {
-                        struct_span_err!(
+                        let spans: Vec<_> = generics.params.iter().map(|i| i.ident.span).collect();
+                        let last = spans.iter().last().map(|s| *s);
+                        let len = spans.len();
+                        let mut err = struct_span_err!(
                             self.session,
-                            item.span,
+                            spans,
                             E0567,
                             "auto traits cannot have generic parameters"
-                        )
-                        .emit();
+                        );
+                        if let Some(span) = last {
+                            err.span_label(
+                                span,
+                                &format!(
+                                    "cannot have {these} generic parameter{s}",
+                                    these = if len == 1 { "this" } else { "these" },
+                                    s = pluralize!(len)
+                                ),
+                            );
+                        }
+                        err.span_label(
+                            item.ident.span,
+                            "auto trait cannot have generic parameters",
+                        );
+                        err.emit();
                     }
                     if !bounds.is_empty() {
-                        struct_span_err!(
+                        let spans: Vec<_> = bounds.iter().map(|b| b.span()).collect();
+                        let last = spans.iter().last().map(|s| *s);
+                        let len = spans.len();
+                        let mut err = struct_span_err!(
                             self.session,
-                            item.span,
+                            spans,
                             E0568,
                             "auto traits cannot have super traits"
-                        )
-                        .emit();
+                        );
+                        if let Some(span) = last {
+                            err.span_label(
+                                span,
+                                &format!(
+                                    "cannot have {these} super trait{s}",
+                                    these = if len == 1 { "this" } else { "these" },
+                                    s = pluralize!(len)
+                                ),
+                            );
+                        }
+                        err.span_label(item.ident.span, "auto trait cannot have super traits");
+                        err.emit();
                     }
                     if !trait_items.is_empty() {
+                        let spans: Vec<_> = trait_items.iter().map(|i| i.ident.span).collect();
                         struct_span_err!(
                             self.session,
-                            item.span,
+                            spans,
                             E0380,
                             "auto traits cannot have methods or associated items"
                         )
+                        .span_label(item.ident.span, "auto trait cannot have items")
                         .emit();
                     }
                 }
@@ -1157,9 +1190,13 @@ impl<'a> Visitor<'a> for AstValidator<'a> {
         }) = fk.header()
         {
             self.err_handler()
-                .struct_span_err(span, "functions cannot be both `const` and `async`")
+                .struct_span_err(
+                    vec![*cspan, *aspan],
+                    "functions cannot be both `const` and `async`",
+                )
                 .span_label(*cspan, "`const` because of this")
                 .span_label(*aspan, "`async` because of this")
+                .span_label(span, "") // Point at the fn header.
                 .emit();
         }
 
diff --git a/src/test/ui/async-await/no-const-async.stderr b/src/test/ui/async-await/no-const-async.stderr
index 07559cd240b..4e59bb50767 100644
--- a/src/test/ui/async-await/no-const-async.stderr
+++ b/src/test/ui/async-await/no-const-async.stderr
@@ -1,8 +1,8 @@
 error: functions cannot be both `const` and `async`
-  --> $DIR/no-const-async.rs:4:1
+  --> $DIR/no-const-async.rs:4:5
    |
 LL | pub const async fn x() {}
-   | ^^^^-----^-----^^^^^^^^^^
+   | ----^^^^^-^^^^^----------
    |     |     |
    |     |     `async` because of this
    |     `const` because of this
diff --git a/src/test/ui/auto-trait-validation.stderr b/src/test/ui/auto-trait-validation.stderr
index 51422fab81f..75919a1f991 100644
--- a/src/test/ui/auto-trait-validation.stderr
+++ b/src/test/ui/auto-trait-validation.stderr
@@ -1,20 +1,26 @@
 error[E0567]: auto traits cannot have generic parameters
-  --> $DIR/auto-trait-validation.rs:3:1
+  --> $DIR/auto-trait-validation.rs:3:20
    |
 LL | auto trait Generic<T> {}
-   | ^^^^^^^^^^^^^^^^^^^^^^^^
+   |            ------- ^ cannot have this generic parameter
+   |            |
+   |            auto trait cannot have generic parameters
 
 error[E0568]: auto traits cannot have super traits
-  --> $DIR/auto-trait-validation.rs:5:1
+  --> $DIR/auto-trait-validation.rs:5:20
    |
 LL | auto trait Bound : Copy {}
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |            -----   ^^^^ cannot have this super trait
+   |            |
+   |            auto trait cannot have super traits
 
 error[E0380]: auto traits cannot have methods or associated items
-  --> $DIR/auto-trait-validation.rs:7:1
+  --> $DIR/auto-trait-validation.rs:7:25
    |
 LL | auto trait MyTrait { fn foo() {} }
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |            -------      ^^^
+   |            |
+   |            auto trait cannot have items
 
 error: aborting due to 3 previous errors
 
diff --git a/src/test/ui/issues/issue-23080-2.rs b/src/test/ui/issues/issue-23080-2.rs
index 319aa2a5cce..d20bb4bd907 100644
--- a/src/test/ui/issues/issue-23080-2.rs
+++ b/src/test/ui/issues/issue-23080-2.rs
@@ -3,8 +3,7 @@
 #![feature(optin_builtin_traits)]
 
 unsafe auto trait Trait {
-//~^ ERROR E0380
-    type Output;
+    type Output; //~ ERROR E0380
 }
 
 fn call_method<T: Trait>(x: T) {}
diff --git a/src/test/ui/issues/issue-23080-2.stderr b/src/test/ui/issues/issue-23080-2.stderr
index 1103de0d910..fcd1ecfa982 100644
--- a/src/test/ui/issues/issue-23080-2.stderr
+++ b/src/test/ui/issues/issue-23080-2.stderr
@@ -1,11 +1,10 @@
 error[E0380]: auto traits cannot have methods or associated items
-  --> $DIR/issue-23080-2.rs:5:1
+  --> $DIR/issue-23080-2.rs:6:10
    |
-LL | / unsafe auto trait Trait {
-LL | |
-LL | |     type Output;
-LL | | }
-   | |_^
+LL | unsafe auto trait Trait {
+   |                   ----- auto trait cannot have items
+LL |     type Output;
+   |          ^^^^^^
 
 error[E0275]: overflow evaluating the requirement `<() as Trait>::Output`
    |
diff --git a/src/test/ui/issues/issue-23080.rs b/src/test/ui/issues/issue-23080.rs
index fdfee698144..fa5c35316bc 100644
--- a/src/test/ui/issues/issue-23080.rs
+++ b/src/test/ui/issues/issue-23080.rs
@@ -1,8 +1,7 @@
 #![feature(optin_builtin_traits)]
 
 unsafe auto trait Trait {
-//~^ ERROR E0380
-    fn method(&self) {
+    fn method(&self) { //~ ERROR E0380
         println!("Hello");
     }
 }
diff --git a/src/test/ui/issues/issue-23080.stderr b/src/test/ui/issues/issue-23080.stderr
index 91c27217324..dbb9861b578 100644
--- a/src/test/ui/issues/issue-23080.stderr
+++ b/src/test/ui/issues/issue-23080.stderr
@@ -1,13 +1,10 @@
 error[E0380]: auto traits cannot have methods or associated items
-  --> $DIR/issue-23080.rs:3:1
+  --> $DIR/issue-23080.rs:4:8
    |
-LL | / unsafe auto trait Trait {
-LL | |
-LL | |     fn method(&self) {
-LL | |         println!("Hello");
-LL | |     }
-LL | | }
-   | |_^
+LL | unsafe auto trait Trait {
+   |                   ----- auto trait cannot have items
+LL |     fn method(&self) {
+   |        ^^^^^^
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/parser/fn-header-semantic-fail.stderr b/src/test/ui/parser/fn-header-semantic-fail.stderr
index 1142cee9851..d6b36fbb714 100644
--- a/src/test/ui/parser/fn-header-semantic-fail.stderr
+++ b/src/test/ui/parser/fn-header-semantic-fail.stderr
@@ -2,7 +2,7 @@ error: functions cannot be both `const` and `async`
   --> $DIR/fn-header-semantic-fail.rs:13:5
    |
 LL |     const async unsafe extern "C" fn ff5() {} // OK.
-   |     -----^-----^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |     ^^^^^-^^^^^------------------------------
    |     |     |
    |     |     `async` because of this
    |     `const` because of this
@@ -45,7 +45,7 @@ error: functions cannot be both `const` and `async`
   --> $DIR/fn-header-semantic-fail.rs:21:9
    |
 LL |         const async unsafe extern "C" fn ft5();
-   |         -----^-----^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |         ^^^^^-^^^^^----------------------------
    |         |     |
    |         |     `async` because of this
    |         `const` because of this
@@ -88,7 +88,7 @@ error: functions cannot be both `const` and `async`
   --> $DIR/fn-header-semantic-fail.rs:34:9
    |
 LL |         const async unsafe extern "C" fn ft5() {}
-   |         -----^-----^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |         ^^^^^-^^^^^------------------------------
    |         |     |
    |         |     `async` because of this
    |         `const` because of this
@@ -97,7 +97,7 @@ error: functions cannot be both `const` and `async`
   --> $DIR/fn-header-semantic-fail.rs:46:9
    |
 LL |         const async unsafe extern "C" fn fi5() {}
-   |         -----^-----^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |         ^^^^^-^^^^^------------------------------
    |         |     |
    |         |     `async` because of this
    |         `const` because of this
@@ -160,7 +160,7 @@ error: functions cannot be both `const` and `async`
   --> $DIR/fn-header-semantic-fail.rs:55:9
    |
 LL |         const async unsafe extern "C" fn fe5();
-   |         -----^-----^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |         ^^^^^-^^^^^----------------------------
    |         |     |
    |         |     `async` because of this
    |         `const` because of this
diff --git a/src/test/ui/traits/traits-inductive-overflow-supertrait-oibit.stderr b/src/test/ui/traits/traits-inductive-overflow-supertrait-oibit.stderr
index 63182a6bd95..03d05f4c928 100644
--- a/src/test/ui/traits/traits-inductive-overflow-supertrait-oibit.stderr
+++ b/src/test/ui/traits/traits-inductive-overflow-supertrait-oibit.stderr
@@ -1,8 +1,10 @@
 error[E0568]: auto traits cannot have super traits
-  --> $DIR/traits-inductive-overflow-supertrait-oibit.rs:7:1
+  --> $DIR/traits-inductive-overflow-supertrait-oibit.rs:7:19
    |
 LL | auto trait Magic: Copy {}
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^
+   |            -----  ^^^^ cannot have this super trait
+   |            |
+   |            auto trait cannot have super traits
 
 error[E0277]: the trait bound `NoClone: std::marker::Copy` is not satisfied
   --> $DIR/traits-inductive-overflow-supertrait-oibit.rs:15:23
diff --git a/src/test/ui/typeck/typeck-auto-trait-no-supertraits-2.stderr b/src/test/ui/typeck/typeck-auto-trait-no-supertraits-2.stderr
index 8755bcded9d..45c95b191bd 100644
--- a/src/test/ui/typeck/typeck-auto-trait-no-supertraits-2.stderr
+++ b/src/test/ui/typeck/typeck-auto-trait-no-supertraits-2.stderr
@@ -1,8 +1,10 @@
 error[E0568]: auto traits cannot have super traits
-  --> $DIR/typeck-auto-trait-no-supertraits-2.rs:3:1
+  --> $DIR/typeck-auto-trait-no-supertraits-2.rs:3:20
    |
 LL | auto trait Magic : Sized where Option<Self> : Magic {}
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |            -----   ^^^^^ cannot have this super trait
+   |            |
+   |            auto trait cannot have super traits
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/typeck/typeck-auto-trait-no-supertraits.stderr b/src/test/ui/typeck/typeck-auto-trait-no-supertraits.stderr
index 5a388834909..094f5d7dd24 100644
--- a/src/test/ui/typeck/typeck-auto-trait-no-supertraits.stderr
+++ b/src/test/ui/typeck/typeck-auto-trait-no-supertraits.stderr
@@ -1,8 +1,10 @@
 error[E0568]: auto traits cannot have super traits
-  --> $DIR/typeck-auto-trait-no-supertraits.rs:27:1
+  --> $DIR/typeck-auto-trait-no-supertraits.rs:27:19
    |
 LL | auto trait Magic: Copy {}
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^
+   |            -----  ^^^^ cannot have this super trait
+   |            |
+   |            auto trait cannot have super traits
 
 error: aborting due to previous error