Rollup merge of #73300 - crlf0710:crate_level_only_check, r=petrochenkov

Implement crate-level-only lints checking.

This implements a crate_level_only flag on lints, and when it is true, it becomes an error when user tries  to specify this flag upon nodes other than crate node.

This also turns on this flag for all non_ascii_ident lints.

8 files changed, 148 insertions, 11 deletions

diff --git a/src/librustc_lint/early.rs b/src/librustc_lint/early.rs
index 06987ffa3d5..d891466611a 100644
--- a/src/librustc_lint/early.rs
+++ b/src/librustc_lint/early.rs
@@ -55,7 +55,8 @@ impl<'a, T: EarlyLintPass> EarlyContextAndPass<'a, T> {
     where
         F: FnOnce(&mut Self),
     {
-        let push = self.context.builder.push(attrs, &self.context.lint_store);
+        let is_crate_node = id == ast::CRATE_NODE_ID;
+        let push = self.context.builder.push(attrs, &self.context.lint_store, is_crate_node);
         self.check_id(id);
         self.enter_attrs(attrs);
         f(self);
diff --git a/src/librustc_lint/levels.rs b/src/librustc_lint/levels.rs
index 05e7c9a0c78..f875e2750a5 100644
--- a/src/librustc_lint/levels.rs
+++ b/src/librustc_lint/levels.rs
@@ -29,7 +29,7 @@ fn lint_levels(tcx: TyCtxt<'_>, cnum: CrateNum) -> LintLevelMap {
     let mut builder = LintLevelMapBuilder { levels, tcx, store };
     let krate = tcx.hir().krate();
 
-    let push = builder.levels.push(&krate.item.attrs, &store);
+    let push = builder.levels.push(&krate.item.attrs, &store, true);
     builder.levels.register_id(hir::CRATE_HIR_ID);
     for macro_def in krate.exported_macros {
         builder.levels.register_id(macro_def.hir_id);
@@ -109,7 +109,12 @@ impl<'s> LintLevelsBuilder<'s> {
     ///   `#[allow]`
     ///
     /// Don't forget to call `pop`!
-    pub fn push(&mut self, attrs: &[ast::Attribute], store: &LintStore) -> BuilderPush {
+    pub fn push(
+        &mut self,
+        attrs: &[ast::Attribute],
+        store: &LintStore,
+        is_crate_node: bool,
+    ) -> BuilderPush {
         let mut specs = FxHashMap::default();
         let sess = self.sess;
         let bad_attr = |span| struct_span_err!(sess, span, E0452, "malformed lint attribute input");
@@ -333,6 +338,40 @@ impl<'s> LintLevelsBuilder<'s> {
             }
         }
 
+        if !is_crate_node {
+            for (id, &(level, ref src)) in specs.iter() {
+                if !id.lint.crate_level_only {
+                    continue;
+                }
+
+                let (lint_attr_name, lint_attr_span) = match *src {
+                    LintSource::Node(name, span, _) => (name, span),
+                    _ => continue,
+                };
+
+                let lint = builtin::UNUSED_ATTRIBUTES;
+                let (lint_level, lint_src) =
+                    self.sets.get_lint_level(lint, self.cur, Some(&specs), self.sess);
+                struct_lint_level(
+                    self.sess,
+                    lint,
+                    lint_level,
+                    lint_src,
+                    Some(lint_attr_span.into()),
+                    |lint| {
+                        let mut db = lint.build(&format!(
+                            "{}({}) is ignored unless specified at crate level",
+                            level.as_str(),
+                            lint_attr_name
+                        ));
+                        db.emit();
+                    },
+                );
+                // don't set a separate error for every lint in the group
+                break;
+            }
+        }
+
         for (id, &(level, ref src)) in specs.iter() {
             if level == Level::Forbid {
                 continue;
@@ -449,7 +488,8 @@ impl LintLevelMapBuilder<'_, '_> {
     where
         F: FnOnce(&mut Self),
     {
-        let push = self.levels.push(attrs, self.store);
+        let is_crate_hir = id == hir::CRATE_HIR_ID;
+        let push = self.levels.push(attrs, self.store, is_crate_hir);
         if push.changed {
             self.levels.register_id(id);
         }
diff --git a/src/librustc_lint/non_ascii_idents.rs b/src/librustc_lint/non_ascii_idents.rs
index ad02b2637d2..064b0255397 100644
--- a/src/librustc_lint/non_ascii_idents.rs
+++ b/src/librustc_lint/non_ascii_idents.rs
@@ -8,20 +8,23 @@ use std::ops::Deref;
 declare_lint! {
     pub NON_ASCII_IDENTS,
     Allow,
-    "detects non-ASCII identifiers"
+    "detects non-ASCII identifiers",
+    crate_level_only
 }
 
 declare_lint! {
     pub UNCOMMON_CODEPOINTS,
     Warn,
-    "detects uncommon Unicode codepoints in identifiers"
+    "detects uncommon Unicode codepoints in identifiers",
+    crate_level_only
 }
 
 // FIXME: Change this to warn.
 declare_lint! {
     pub CONFUSABLE_IDENTS,
     Allow,
-    "detects visually confusable pairs between identifiers"
+    "detects visually confusable pairs between identifiers",
+    crate_level_only
 }
 
 declare_lint_pass!(NonAsciiIdents => [NON_ASCII_IDENTS, UNCOMMON_CODEPOINTS, CONFUSABLE_IDENTS]);
diff --git a/src/librustc_session/lint.rs b/src/librustc_session/lint.rs
index ffb45793090..0dcbee08abe 100644
--- a/src/librustc_session/lint.rs
+++ b/src/librustc_session/lint.rs
@@ -88,6 +88,8 @@ pub struct Lint {
 
     /// `Some` if this lint is feature gated, otherwise `None`.
     pub feature_gate: Option<Symbol>,
+
+    pub crate_level_only: bool,
 }
 
 /// Extra information for a future incompatibility lint.
@@ -111,6 +113,7 @@ impl Lint {
             report_in_external_macro: false,
             future_incompatible: None,
             feature_gate: None,
+            crate_level_only: false,
         }
     }
 
@@ -336,6 +339,7 @@ macro_rules! declare_tool_lint {
             future_incompatible: None,
             is_plugin: true,
             feature_gate: None,
+            crate_level_only: false,
         };
     );
 }
diff --git a/src/librustc_session/lint/builtin.rs b/src/librustc_session/lint/builtin.rs
index 5a8f5c1b9fb..5deee6eb48e 100644
--- a/src/librustc_session/lint/builtin.rs
+++ b/src/librustc_session/lint/builtin.rs
@@ -17,6 +17,7 @@ declare_lint! {
         reference: "issue #57571 <https://github.com/rust-lang/rust/issues/57571>",
         edition: None,
     };
+    crate_level_only
 }
 
 declare_lint! {
@@ -75,7 +76,8 @@ declare_lint! {
 declare_lint! {
     pub UNUSED_CRATE_DEPENDENCIES,
     Allow,
-    "crate dependencies that are never used"
+    "crate dependencies that are never used",
+    crate_level_only
 }
 
 declare_lint! {
@@ -166,7 +168,8 @@ declare_lint! {
 declare_lint! {
     pub UNKNOWN_CRATE_TYPES,
     Deny,
-    "unknown crate type found in `#[crate_type]` directive"
+    "unknown crate type found in `#[crate_type]` directive",
+    crate_level_only
 }
 
 declare_lint! {
@@ -339,7 +342,8 @@ declare_lint! {
 declare_lint! {
     pub ELIDED_LIFETIMES_IN_PATHS,
     Allow,
-    "hidden lifetime parameters in types are deprecated"
+    "hidden lifetime parameters in types are deprecated",
+    crate_level_only
 }
 
 declare_lint! {
@@ -459,6 +463,7 @@ declare_lint! {
         reference: "issue #52234 <https://github.com/rust-lang/rust/issues/52234>",
         edition: None,
     };
+    crate_level_only
 }
 
 declare_lint! {
diff --git a/src/test/ui/issues/issue-48508.rs b/src/test/ui/issues/issue-48508.rs
index 87965c204ad..8dc9351260e 100644
--- a/src/test/ui/issues/issue-48508.rs
+++ b/src/test/ui/issues/issue-48508.rs
@@ -11,7 +11,7 @@
 // ignore-asmjs wasm2js does not support source maps yet
 
 #![feature(non_ascii_idents)]
-#[allow(uncommon_codepoints)]
+#![allow(uncommon_codepoints)]
 
 #[path = "issue-48508-aux.rs"]
 mod other_file;
diff --git a/src/test/ui/lint/crate_level_only_lint.rs b/src/test/ui/lint/crate_level_only_lint.rs
new file mode 100644
index 00000000000..d9673faa214
--- /dev/null
+++ b/src/test/ui/lint/crate_level_only_lint.rs
@@ -0,0 +1,22 @@
+#![deny(uncommon_codepoints, unused_attributes)]
+
+mod foo {
+#![allow(uncommon_codepoints)]
+//~^ ERROR allow(uncommon_codepoints) is ignored unless specified at crate level [unused_attributes]
+//~| ERROR allow(uncommon_codepoints) is ignored unless specified at crate level [unused_attributes]
+//~| ERROR allow(uncommon_codepoints) is ignored unless specified at crate level [unused_attributes]
+
+#[allow(uncommon_codepoints)]
+//~^ ERROR allow(uncommon_codepoints) is ignored unless specified at crate level [unused_attributes]
+//~| ERROR allow(uncommon_codepoints) is ignored unless specified at crate level [unused_attributes]
+//~| ERROR allow(uncommon_codepoints) is ignored unless specified at crate level [unused_attributes]
+const BAR: f64 = 0.000001;
+
+}
+
+#[allow(uncommon_codepoints)]
+//~^ ERROR allow(uncommon_codepoints) is ignored unless specified at crate level [unused_attributes]
+//~| ERROR allow(uncommon_codepoints) is ignored unless specified at crate level [unused_attributes]
+//~| ERROR allow(uncommon_codepoints) is ignored unless specified at crate level [unused_attributes]
+fn main() {
+}
diff --git a/src/test/ui/lint/crate_level_only_lint.stderr b/src/test/ui/lint/crate_level_only_lint.stderr
new file mode 100644
index 00000000000..8fb06df2a48
--- /dev/null
+++ b/src/test/ui/lint/crate_level_only_lint.stderr
@@ -0,0 +1,62 @@
+error: allow(uncommon_codepoints) is ignored unless specified at crate level
+  --> $DIR/crate_level_only_lint.rs:4:10
+   |
+LL | #![allow(uncommon_codepoints)]
+   |          ^^^^^^^^^^^^^^^^^^^
+   |
+note: the lint level is defined here
+  --> $DIR/crate_level_only_lint.rs:1:30
+   |
+LL | #![deny(uncommon_codepoints, unused_attributes)]
+   |                              ^^^^^^^^^^^^^^^^^
+
+error: allow(uncommon_codepoints) is ignored unless specified at crate level
+  --> $DIR/crate_level_only_lint.rs:9:9
+   |
+LL | #[allow(uncommon_codepoints)]
+   |         ^^^^^^^^^^^^^^^^^^^
+
+error: allow(uncommon_codepoints) is ignored unless specified at crate level
+  --> $DIR/crate_level_only_lint.rs:17:9
+   |
+LL | #[allow(uncommon_codepoints)]
+   |         ^^^^^^^^^^^^^^^^^^^
+
+error: allow(uncommon_codepoints) is ignored unless specified at crate level
+  --> $DIR/crate_level_only_lint.rs:4:10
+   |
+LL | #![allow(uncommon_codepoints)]
+   |          ^^^^^^^^^^^^^^^^^^^
+
+error: allow(uncommon_codepoints) is ignored unless specified at crate level
+  --> $DIR/crate_level_only_lint.rs:9:9
+   |
+LL | #[allow(uncommon_codepoints)]
+   |         ^^^^^^^^^^^^^^^^^^^
+
+error: allow(uncommon_codepoints) is ignored unless specified at crate level
+  --> $DIR/crate_level_only_lint.rs:17:9
+   |
+LL | #[allow(uncommon_codepoints)]
+   |         ^^^^^^^^^^^^^^^^^^^
+
+error: allow(uncommon_codepoints) is ignored unless specified at crate level
+  --> $DIR/crate_level_only_lint.rs:4:10
+   |
+LL | #![allow(uncommon_codepoints)]
+   |          ^^^^^^^^^^^^^^^^^^^
+
+error: allow(uncommon_codepoints) is ignored unless specified at crate level
+  --> $DIR/crate_level_only_lint.rs:9:9
+   |
+LL | #[allow(uncommon_codepoints)]
+   |         ^^^^^^^^^^^^^^^^^^^
+
+error: allow(uncommon_codepoints) is ignored unless specified at crate level
+  --> $DIR/crate_level_only_lint.rs:17:9
+   |
+LL | #[allow(uncommon_codepoints)]
+   |         ^^^^^^^^^^^^^^^^^^^
+
+error: aborting due to 9 previous errors
+