Add explanatory note to 'expected item' error

14 files changed, 41 insertions, 4 deletions

diff --git a/compiler/rustc_parse/src/parser/item.rs b/compiler/rustc_parse/src/parser/item.rs
index 233c7016417..aad4edaba90 100644
--- a/compiler/rustc_parse/src/parser/item.rs
+++ b/compiler/rustc_parse/src/parser/item.rs
@@ -73,12 +73,16 @@ impl<'a> Parser<'a> {
             if !self.maybe_consume_incorrect_semicolon(&items) {
                 let msg = format!("expected item, found {token_str}");
                 let mut err = self.struct_span_err(self.token.span, msg);
-                let label = if self.is_kw_followed_by_ident(kw::Let) {
-                    "consider using `const` or `static` instead of `let` for global variables"
+                let span = self.token.span;
+                if self.is_kw_followed_by_ident(kw::Let) {
+                    err.span_label(
+                        span,
+                        "consider using `const` or `static` instead of `let` for global variables",
+                    );
                 } else {
-                    "expected item"
+                    err.span_label(span, "expected item")
+                        .note("for a full list of items that can appear in modules, see <https://doc.rust-lang.org/reference/items.html>");
                 };
-                err.span_label(self.token.span, label);
                 return Err(err);
             }
         }
diff --git a/tests/ui/fn/keyword-order.stderr b/tests/ui/fn/keyword-order.stderr
index d3b140c8528..97d8f91b1ee 100644
--- a/tests/ui/fn/keyword-order.stderr
+++ b/tests/ui/fn/keyword-order.stderr
@@ -11,6 +11,8 @@ error: expected item, found keyword `pub`
    |
 LL | default pub const async unsafe extern fn err() {}
    |         ^^^ expected item
+   |
+   = note: for a full list of items that can appear in modules, see <https://doc.rust-lang.org/reference/items.html>
 
 error: aborting due to 2 previous errors
 
diff --git a/tests/ui/parser/default-unmatched.stderr b/tests/ui/parser/default-unmatched.stderr
index 331e003f63c..de142411d69 100644
--- a/tests/ui/parser/default-unmatched.stderr
+++ b/tests/ui/parser/default-unmatched.stderr
@@ -11,6 +11,8 @@ error: expected item, found reserved keyword `do`
    |
 LL |     default do
    |             ^^ expected item
+   |
+   = note: for a full list of items that can appear in modules, see <https://doc.rust-lang.org/reference/items.html>
 
 error: aborting due to 2 previous errors
 
diff --git a/tests/ui/parser/impl-parsing.stderr b/tests/ui/parser/impl-parsing.stderr
index 755addf1452..a57cc075ccc 100644
--- a/tests/ui/parser/impl-parsing.stderr
+++ b/tests/ui/parser/impl-parsing.stderr
@@ -35,6 +35,8 @@ error: expected item, found keyword `unsafe`
    |
 LL | default unsafe FAIL
    |         ^^^^^^ expected item
+   |
+   = note: for a full list of items that can appear in modules, see <https://doc.rust-lang.org/reference/items.html>
 
 error: aborting due to 6 previous errors
 
diff --git a/tests/ui/parser/issue-101477-enum.stderr b/tests/ui/parser/issue-101477-enum.stderr
index 1edca391e8f..94130671f1c 100644
--- a/tests/ui/parser/issue-101477-enum.stderr
+++ b/tests/ui/parser/issue-101477-enum.stderr
@@ -11,6 +11,8 @@ error: expected item, found `==`
    |
 LL |     B == 2
    |       ^^ expected item
+   |
+   = note: for a full list of items that can appear in modules, see <https://doc.rust-lang.org/reference/items.html>
 
 error: aborting due to 2 previous errors
 
diff --git a/tests/ui/parser/issues/issue-113110-non-item-at-module-root.rs b/tests/ui/parser/issues/issue-113110-non-item-at-module-root.rs
new file mode 100644
index 00000000000..3b6f4304369
--- /dev/null
+++ b/tests/ui/parser/issues/issue-113110-non-item-at-module-root.rs
@@ -0,0 +1 @@
+ 5 //~ ERROR expected item, found `5`
diff --git a/tests/ui/parser/issues/issue-113110-non-item-at-module-root.stderr b/tests/ui/parser/issues/issue-113110-non-item-at-module-root.stderr
new file mode 100644
index 00000000000..0789c4548a0
--- /dev/null
+++ b/tests/ui/parser/issues/issue-113110-non-item-at-module-root.stderr
@@ -0,0 +1,10 @@
+error: expected item, found `5`
+  --> $DIR/issue-113110-non-item-at-module-root.rs:1:2
+   |
+LL |  5
+   |  ^ expected item
+   |
+   = note: for a full list of items that can appear in modules, see <https://doc.rust-lang.org/reference/items.html>
+
+error: aborting due to previous error
+
diff --git a/tests/ui/parser/issues/issue-17904-2.stderr b/tests/ui/parser/issues/issue-17904-2.stderr
index 9c7fdf6ccb4..7185a5e5752 100644
--- a/tests/ui/parser/issues/issue-17904-2.stderr
+++ b/tests/ui/parser/issues/issue-17904-2.stderr
@@ -3,6 +3,8 @@ error: expected item, found keyword `where`
    |
 LL | struct Bar<T> { x: T } where T: Copy
    |                        ^^^^^ expected item
+   |
+   = note: for a full list of items that can appear in modules, see <https://doc.rust-lang.org/reference/items.html>
 
 error: aborting due to previous error
 
diff --git a/tests/ui/parser/issues/issue-43196.stderr b/tests/ui/parser/issues/issue-43196.stderr
index 4f7ed5cc6fd..15bbb158cd1 100644
--- a/tests/ui/parser/issues/issue-43196.stderr
+++ b/tests/ui/parser/issues/issue-43196.stderr
@@ -11,6 +11,8 @@ error: expected item, found `|`
    |
 LL | |
    | ^ expected item
+   |
+   = note: for a full list of items that can appear in modules, see <https://doc.rust-lang.org/reference/items.html>
 
 error: aborting due to 2 previous errors
 
diff --git a/tests/ui/parser/issues/issue-62913.stderr b/tests/ui/parser/issues/issue-62913.stderr
index 6f385e8dc17..c33e4683728 100644
--- a/tests/ui/parser/issues/issue-62913.stderr
+++ b/tests/ui/parser/issues/issue-62913.stderr
@@ -17,6 +17,8 @@ error: expected item, found `"\u\"`
    |
 LL | "\u\"
    | ^^^^^^ expected item
+   |
+   = note: for a full list of items that can appear in modules, see <https://doc.rust-lang.org/reference/items.html>
 
 error: aborting due to 3 previous errors
 
diff --git a/tests/ui/parser/issues/issue-68890.stderr b/tests/ui/parser/issues/issue-68890.stderr
index 2a3bf6b41f0..0d7b53a67c5 100644
--- a/tests/ui/parser/issues/issue-68890.stderr
+++ b/tests/ui/parser/issues/issue-68890.stderr
@@ -15,6 +15,8 @@ error: expected item, found `)`
    |
 LL | enum e{A((?'a a+?+l))}
    |                     ^ expected item
+   |
+   = note: for a full list of items that can appear in modules, see <https://doc.rust-lang.org/reference/items.html>
 
 error: aborting due to 3 previous errors
 
diff --git a/tests/ui/parser/shebang/shebang-doc-comment.stderr b/tests/ui/parser/shebang/shebang-doc-comment.stderr
index 2227d45ec5a..a36b2a2f72b 100644
--- a/tests/ui/parser/shebang/shebang-doc-comment.stderr
+++ b/tests/ui/parser/shebang/shebang-doc-comment.stderr
@@ -3,6 +3,8 @@ error: expected item, found `[`
    |
 LL | [allow(unused_variables)]
    | ^ expected item
+   |
+   = note: for a full list of items that can appear in modules, see <https://doc.rust-lang.org/reference/items.html>
 
 error: aborting due to previous error
 
diff --git a/tests/ui/parser/virtual-structs.stderr b/tests/ui/parser/virtual-structs.stderr
index a5211d83f84..268fc105796 100644
--- a/tests/ui/parser/virtual-structs.stderr
+++ b/tests/ui/parser/virtual-structs.stderr
@@ -3,6 +3,8 @@ error: expected item, found reserved keyword `virtual`
    |
 LL | virtual struct SuperStruct {
    | ^^^^^^^ expected item
+   |
+   = note: for a full list of items that can appear in modules, see <https://doc.rust-lang.org/reference/items.html>
 
 error: aborting due to previous error
 
diff --git a/tests/ui/pub/pub-restricted-error-fn.stderr b/tests/ui/pub/pub-restricted-error-fn.stderr
index 0511a821a7a..ca5d8e1b58e 100644
--- a/tests/ui/pub/pub-restricted-error-fn.stderr
+++ b/tests/ui/pub/pub-restricted-error-fn.stderr
@@ -11,6 +11,8 @@ error: expected item, found `(`
    |
 LL | pub(crate) () fn foo() {}
    |            ^ expected item
+   |
+   = note: for a full list of items that can appear in modules, see <https://doc.rust-lang.org/reference/items.html>
 
 error: aborting due to 2 previous errors