From d82292e1ce8112cfa5e42d0221a563649d067747 Mon Sep 17 00:00:00 2001
From: Jonas Schievink <jonasschievink@gmail.com>
Date: Thu, 10 Dec 2020 15:45:01 +0100
Subject: [PATCH] Ignore extern items in incorrect-case check

---
 crates/hir_def/src/data.rs                  |  4 ++++
 crates/hir_def/src/item_tree.rs             |  5 +++++
 crates/hir_def/src/item_tree/lower.rs       | 13 ++++++++-----
 crates/hir_ty/src/diagnostics/decl_check.rs | 19 +++++++++++++++++++
 4 files changed, 36 insertions(+), 5 deletions(-)

diff --git a/crates/hir_def/src/data.rs b/crates/hir_def/src/data.rs
index 14604593832..dd3a906af0c 100644
--- a/crates/hir_def/src/data.rs
+++ b/crates/hir_def/src/data.rs
@@ -28,6 +28,7 @@ pub struct FunctionData {
     pub has_body: bool,
     pub is_unsafe: bool,
     pub is_varargs: bool,
+    pub is_extern: bool,
     pub visibility: RawVisibility,
 }
 
@@ -46,6 +47,7 @@ impl FunctionData {
             has_body: func.has_body,
             is_unsafe: func.is_unsafe,
             is_varargs: func.is_varargs,
+            is_extern: func.is_extern,
             visibility: item_tree[func.visibility].clone(),
         })
     }
@@ -191,6 +193,7 @@ pub struct StaticData {
     pub type_ref: TypeRef,
     pub visibility: RawVisibility,
     pub mutable: bool,
+    pub is_extern: bool,
 }
 
 impl StaticData {
@@ -204,6 +207,7 @@ impl StaticData {
             type_ref: statik.type_ref.clone(),
             visibility: item_tree[statik.visibility].clone(),
             mutable: statik.mutable,
+            is_extern: statik.is_extern,
         })
     }
 }
diff --git a/crates/hir_def/src/item_tree.rs b/crates/hir_def/src/item_tree.rs
index 7eb388baed5..b3ec252fd59 100644
--- a/crates/hir_def/src/item_tree.rs
+++ b/crates/hir_def/src/item_tree.rs
@@ -507,6 +507,9 @@ pub struct Function {
     pub has_self_param: bool,
     pub has_body: bool,
     pub is_unsafe: bool,
+    /// Whether the function is located in an `extern` block (*not* whether it is an
+    /// `extern "abi" fn`).
+    pub is_extern: bool,
     pub params: Box<[TypeRef]>,
     pub is_varargs: bool,
     pub ret_type: TypeRef,
@@ -565,6 +568,8 @@ pub struct Static {
     pub name: Name,
     pub visibility: RawVisibilityId,
     pub mutable: bool,
+    /// Whether the static is in an `extern` block.
+    pub is_extern: bool,
     pub type_ref: TypeRef,
     pub ast_id: FileAstId<ast::Static>,
 }
diff --git a/crates/hir_def/src/item_tree/lower.rs b/crates/hir_def/src/item_tree/lower.rs
index ca7fb4a43db..63b2826f857 100644
--- a/crates/hir_def/src/item_tree/lower.rs
+++ b/crates/hir_def/src/item_tree/lower.rs
@@ -340,6 +340,7 @@ impl Ctx {
             has_self_param,
             has_body,
             is_unsafe: func.unsafe_token().is_some(),
+            is_extern: false,
             params: params.into_boxed_slice(),
             is_varargs,
             ret_type,
@@ -378,7 +379,7 @@ impl Ctx {
         let visibility = self.lower_visibility(static_);
         let mutable = static_.mut_token().is_some();
         let ast_id = self.source_ast_id_map.ast_id(static_);
-        let res = Static { name, visibility, mutable, type_ref, ast_id };
+        let res = Static { name, visibility, mutable, type_ref, ast_id, is_extern: false };
         Some(id(self.data().statics.alloc(res)))
     }
 
@@ -554,13 +555,15 @@ impl Ctx {
                     let attrs = Attrs::new(&item, &self.hygiene);
                     let id: ModItem = match item {
                         ast::ExternItem::Fn(ast) => {
-                            let func = self.lower_function(&ast)?;
-                            self.data().functions[func.index].is_unsafe =
-                                is_intrinsic_fn_unsafe(&self.data().functions[func.index].name);
-                            func.into()
+                            let func_id = self.lower_function(&ast)?;
+                            let func = &mut self.data().functions[func_id.index];
+                            func.is_unsafe = is_intrinsic_fn_unsafe(&func.name);
+                            func.is_extern = true;
+                            func_id.into()
                         }
                         ast::ExternItem::Static(ast) => {
                             let statik = self.lower_static(&ast)?;
+                            self.data().statics[statik.index].is_extern = true;
                             statik.into()
                         }
                         ast::ExternItem::TypeAlias(ty) => {
diff --git a/crates/hir_ty/src/diagnostics/decl_check.rs b/crates/hir_ty/src/diagnostics/decl_check.rs
index 4b3e2fa8f66..724bad867dd 100644
--- a/crates/hir_ty/src/diagnostics/decl_check.rs
+++ b/crates/hir_ty/src/diagnostics/decl_check.rs
@@ -87,6 +87,10 @@ impl<'a, 'b> DeclValidator<'a, 'b> {
 
     fn validate_func(&mut self, db: &dyn HirDatabase, func: FunctionId) {
         let data = db.function_data(func);
+        if data.is_extern {
+            return;
+        }
+
         let body = db.body(func.into());
 
         // Recursively validate inner scope items, such as static variables and constants.
@@ -648,6 +652,9 @@ impl<'a, 'b> DeclValidator<'a, 'b> {
 
     fn validate_static(&mut self, db: &dyn HirDatabase, static_id: StaticId) {
         let data = db.static_data(static_id);
+        if data.is_extern {
+            return;
+        }
 
         if self.allowed(db, static_id.into(), allow::NON_UPPER_CASE_GLOBAL) {
             return;
@@ -920,4 +927,16 @@ fn main() {
     "#,
         );
     }
+
+    #[test]
+    fn ignores_extern_items() {
+        check_diagnostics(
+            r#"
+extern {
+    fn NonSnakeCaseName(SOME_VAR: u8) -> u8;
+    pub static SomeStatic: u8 = 10;
+}
+            "#,
+        );
+    }
 }