Specify scope in out_of_scope_macro_calls lint

```
warning: cannot find macro `in_root` in the crate root
  --> $DIR/key-value-expansion-scope.rs:1:10
   |
LL | #![doc = in_root!()]
   |          ^^^^^^^ not found in the crate root
   |
   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
   = note: for more information, see issue #124535 <#124535>
   = help: import `macro_rules` with `use` to make it callable above its definition
   = note: `#[warn(out_of_scope_macro_calls)]` on by default
```

Author: estebank

compiler/rustc_lint/messages.ftl

@@ -624,7 +624,8 @@ lint_opaque_hidden_inferred_bound_sugg = add this bound
 lint_or_patterns_back_compat = the meaning of the `pat` fragment specifier is changing in Rust 2021, which may affect this macro
     .suggestion = use pat_param to preserve semantics
 
-lint_out_of_scope_macro_calls = cannot find macro `{$path}` in this scope
+lint_out_of_scope_macro_calls = cannot find macro `{$path}` in {$scope}
+    .label = not found in {$scope}
     .help = import `macro_rules` with `use` to make it callable above its definition
 
 lint_overflowing_bin_hex = literal out of range for `{$ty}`

compiler/rustc_lint/src/context/diagnostics.rs

@@ -434,8 +434,8 @@ pub(super) fn decorate_lint(sess: &Session, diagnostic: BuiltinLintDiag, diag: &
             lints::InnerAttributeUnstable::CustomInnerAttribute
         }
         .decorate_lint(diag),
-        BuiltinLintDiag::OutOfScopeMacroCalls { path } => {
-            lints::OutOfScopeMacroCalls { path }.decorate_lint(diag)
+        BuiltinLintDiag::OutOfScopeMacroCalls { span, path, scope } => {
+            lints::OutOfScopeMacroCalls { span, path, scope }.decorate_lint(diag)
         }
     }
 }

compiler/rustc_lint/src/lints.rs

@@ -2951,5 +2951,8 @@ pub struct UnsafeAttrOutsideUnsafeSuggestion {
 #[diag(lint_out_of_scope_macro_calls)]
 #[help]
 pub struct OutOfScopeMacroCalls {
+    #[label]
+    pub span: Span,
     pub path: String,
+    pub scope: String,
 }

compiler/rustc_lint_defs/src/lib.rs

@@ -745,7 +745,9 @@ pub enum BuiltinLintDiag {
         is_macro: bool,
     },
     OutOfScopeMacroCalls {
+        span: Span,
         path: String,
+        scope: String,
     },
 }
 

compiler/rustc_resolve/src/macros.rs

@@ -862,8 +862,10 @@ impl<'a, 'tcx> Resolver<'a, 'tcx> {
                 ),
                 path_res @ (PathResult::NonModule(..) | PathResult::Failed { .. }) => {
                     let mut suggestion = None;
-                    let (span, label, module) =
-                        if let PathResult::Failed { span, label, module, .. } = path_res {
+                    let (span, label, module, segment) =
+                        if let PathResult::Failed { span, label, module, segment_name, .. } =
+                            path_res
+                        {
                             // try to suggest if it's not a macro, maybe a function
                             if let PathResult::NonModule(partial_res) =
                                 self.maybe_resolve_path(&path, Some(ValueNS), &parent_scope)
@@ -881,7 +883,7 @@ impl<'a, 'tcx> Resolver<'a, 'tcx> {
                                     Applicability::MaybeIncorrect,
                                 ));
                             }
-                            (span, label, module)
+                            (span, label, module, segment_name)
                         } else {
                             (
                                 path_span,
@@ -891,12 +893,13 @@ impl<'a, 'tcx> Resolver<'a, 'tcx> {
                                     kind.descr()
                                 ),
                                 None,
+                                path.last().map(|segment| segment.ident.name).unwrap(),
                             )
                         };
                     self.report_error(
                         span,
                         ResolutionError::FailedToResolve {
-                            segment: path.last().map(|segment| segment.ident.name),
+                            segment: Some(segment),
                             label,
                             suggestion,
                             module,
@@ -1067,11 +1070,24 @@ impl<'a, 'tcx> Resolver<'a, 'tcx> {
                 None,
             );
             if fallback_binding.ok().and_then(|b| b.res().opt_def_id()) != Some(def_id) {
+                let scope = match parent_scope.module.kind {
+                    ModuleKind::Def(_, _, name) if name == kw::Empty => {
+                        "the crate root".to_string()
+                    }
+                    ModuleKind::Def(kind, def_id, name) => {
+                        format!("{} `{name}`", kind.descr(def_id))
+                    }
+                    ModuleKind::Block => "this scope".to_string(),
+                };
                 self.tcx.sess.psess.buffer_lint(
                     OUT_OF_SCOPE_MACRO_CALLS,
                     path.span,
                     node_id,
-                    BuiltinLintDiag::OutOfScopeMacroCalls { path: pprust::path_to_string(path) },
+                    BuiltinLintDiag::OutOfScopeMacroCalls {
+                        span: path.span,
+                        path: pprust::path_to_string(path),
+                        scope,
+                    },
                 );
             }
         }

tests/ui/attributes/key-value-expansion-scope.rs

@@ -1,7 +1,7 @@
-#![doc = in_root!()] //~ WARN cannot find macro `in_root` in this scope
+#![doc = in_root!()] //~ WARN cannot find macro `in_root`
                      //~| WARN this was previously accepted by the compiler
 #![doc = in_mod!()] //~ ERROR cannot find macro `in_mod` in this scope
-#![doc = in_mod_escape!()] //~ WARN cannot find macro `in_mod_escape` in this scope
+#![doc = in_mod_escape!()] //~ WARN cannot find macro `in_mod_escape`
                            //~| WARN this was previously accepted by the compiler
 #![doc = in_block!()] //~ ERROR cannot find macro `in_block` in this scope
 
@@ -18,10 +18,10 @@ fn before() {
 
 macro_rules! in_root { () => { "" } }
 
-#[doc = in_mod!()] //~ WARN cannot find macro `in_mod` in this scope
+#[doc = in_mod!()] //~ WARN cannot find macro `in_mod`
                    //~| WARN this was previously accepted by the compiler
 mod macros_stay {
-    #![doc = in_mod!()] //~ WARN cannot find macro `in_mod` in this scope
+    #![doc = in_mod!()] //~ WARN cannot find macro `in_mod`
                         //~| WARN this was previously accepted by the compiler
 
     macro_rules! in_mod { () => { "" } }
@@ -33,10 +33,10 @@ mod macros_stay {
 }
 
 #[macro_use]
-#[doc = in_mod_escape!()] //~ WARN cannot find macro `in_mod_escape` in this scope
+#[doc = in_mod_escape!()] //~ WARN cannot find macro `in_mod_escape`
                           //~| WARN this was previously accepted by the compiler
 mod macros_escape {
-    #![doc = in_mod_escape!()] //~ WARN cannot find macro `in_mod_escape` in this scope
+    #![doc = in_mod_escape!()] //~ WARN cannot find macro `in_mod_escape`
                                //~| WARN this was previously accepted by the compiler
 
     macro_rules! in_mod_escape { () => { "" } }

tests/ui/attributes/key-value-expansion-scope.stderr

@@ -126,62 +126,62 @@ LL |     #![doc = in_block!()]
    |
    = help: have you added the `#[macro_use]` on the module/import?
 
-warning: cannot find macro `in_root` in this scope
+warning: cannot find macro `in_root` in the crate root
   --> $DIR/key-value-expansion-scope.rs:1:10
    |
 LL | #![doc = in_root!()]
-   |          ^^^^^^^
+   |          ^^^^^^^ not found in the crate root
    |
    = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
    = note: for more information, see issue #124535 <https://github.com/rust-lang/rust/issues/124535>
    = help: import `macro_rules` with `use` to make it callable above its definition
    = note: `#[warn(out_of_scope_macro_calls)]` on by default
 
-warning: cannot find macro `in_mod_escape` in this scope
+warning: cannot find macro `in_mod_escape` in the crate root
   --> $DIR/key-value-expansion-scope.rs:4:10
    |
 LL | #![doc = in_mod_escape!()]
-   |          ^^^^^^^^^^^^^
+   |          ^^^^^^^^^^^^^ not found in the crate root
    |
    = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
    = note: for more information, see issue #124535 <https://github.com/rust-lang/rust/issues/124535>
    = help: import `macro_rules` with `use` to make it callable above its definition
 
-warning: cannot find macro `in_mod` in this scope
+warning: cannot find macro `in_mod` in module `macros_stay`
   --> $DIR/key-value-expansion-scope.rs:21:9
    |
 LL | #[doc = in_mod!()]
-   |         ^^^^^^
+   |         ^^^^^^ not found in module `macros_stay`
    |
    = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
    = note: for more information, see issue #124535 <https://github.com/rust-lang/rust/issues/124535>
    = help: import `macro_rules` with `use` to make it callable above its definition
 
-warning: cannot find macro `in_mod` in this scope
+warning: cannot find macro `in_mod` in module `macros_stay`
   --> $DIR/key-value-expansion-scope.rs:24:14
    |
 LL |     #![doc = in_mod!()]
-   |              ^^^^^^
+   |              ^^^^^^ not found in module `macros_stay`
    |
    = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
    = note: for more information, see issue #124535 <https://github.com/rust-lang/rust/issues/124535>
    = help: import `macro_rules` with `use` to make it callable above its definition
 
-warning: cannot find macro `in_mod_escape` in this scope
+warning: cannot find macro `in_mod_escape` in module `macros_escape`
   --> $DIR/key-value-expansion-scope.rs:36:9
    |
 LL | #[doc = in_mod_escape!()]
-   |         ^^^^^^^^^^^^^
+   |         ^^^^^^^^^^^^^ not found in module `macros_escape`
    |
    = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
    = note: for more information, see issue #124535 <https://github.com/rust-lang/rust/issues/124535>
    = help: import `macro_rules` with `use` to make it callable above its definition
 
-warning: cannot find macro `in_mod_escape` in this scope
+warning: cannot find macro `in_mod_escape` in module `macros_escape`
   --> $DIR/key-value-expansion-scope.rs:39:14
    |
 LL |     #![doc = in_mod_escape!()]
-   |              ^^^^^^^^^^^^^
+   |              ^^^^^^^^^^^^^ not found in module `macros_escape`
    |
    = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
    = note: for more information, see issue #124535 <https://github.com/rust-lang/rust/issues/124535>