Add checks for enums in scan-deadcode

gcc/rust/checks/lints/rust-lint-scan-deadcode.h

@@ -21,6 +21,7 @@
 
 #include "rust-hir-full-decls.h"
 #include "rust-hir-map.h"
+#include "rust-hir-visibility.h"
 #include "rust-lint-marklive.h"
 #include "rust-name-resolver.h"
 #include "rust-diagnostics.h"
@@ -29,12 +30,13 @@ namespace Rust {
 namespace Analysis {
 
 // Scan item symbols and warn the symbol if it is not in the live_symbols set.
-// There are three kinds of item we should handle in this pass.
+// There are four kinds of item we should handle in this pass.
 // 1. Function item
 // 2. The function item in the impl block without trait
 // 3. StructStruct, e.g., `Struct Foo{one: 1, two: 2}`. Furthermore, the unused
 //    struct fields will be warned too.
 // 4. TupleStruct, e.g., `Struct Foo(i32, i32)`
+// 5. Enum, e.g., `enum Foo { A, B }`
 class ScanDeadcode : public MarkLiveBase
 {
   using Rust::Analysis::MarkLiveBase::visit;
@@ -48,13 +50,16 @@ class ScanDeadcode : public MarkLiveBase
       it.get ()->accept_vis (sdc);
   };
 
+  bool name_starts_with_underscore (const Identifier &identifier)
+  {
+    return identifier.as_string ().rfind ('_', 0) == 0;
+  }
+
   void visit (HIR::Function &function) override
   {
     HirId hirId = function.get_mappings ().get_hirid ();
-    auto starts_with_underscore
-      = function.get_function_name ().as_string ().rfind ('_', 0) == 0;
-    if (should_warn (hirId) && !function.get_visibility ().is_public ()
-	&& !starts_with_underscore)
+    if (should_warn (hirId, function.get_function_name (),
+		     function.get_visibility ()))
       {
 	if (mappings.is_impl_item (hirId))
 	  {
@@ -77,46 +82,48 @@ class ScanDeadcode : public MarkLiveBase
       }
   }
 
-  void visit (HIR::StructStruct &stct) override
+  void visit (HIR::StructStruct &strukt) override
   {
-    HirId hirId = stct.get_mappings ().get_hirid ();
-    if (should_warn (hirId) && !stct.get_visibility ().is_public ())
+    HirId hirId = strukt.get_mappings ().get_hirid ();
+    if (should_warn (hirId, strukt.get_identifier (), strukt.get_visibility ()))
       {
-	bool name_starts_underscore
-	  = stct.get_identifier ().as_string ().at (0) == '_';
-	if (!name_starts_underscore)
-	  rust_warning_at (stct.get_locus (), 0,
-			   "struct is never constructed: %qs",
-			   stct.get_identifier ().as_string ().c_str ());
+	rust_warning_at (strukt.get_locus (), 0,
+			 "struct is never constructed: %qs",
+			 strukt.get_identifier ().as_string ().c_str ());
       }
-    else
+    else if (!name_starts_with_underscore (strukt.get_identifier ()))
       {
-	// only warn the unused fields when in unwarned struct.
-	for (auto &field : stct.get_fields ())
+	// only warn the unused fields when in unwarned struct and if its name
+	// doesn't start with an underscore
+
+	for (auto &field : strukt.get_fields ())
 	  {
 	    HirId field_hir_id = field.get_mappings ().get_hirid ();
-	    if (should_warn (field_hir_id)
-		&& !field.get_visibility ().is_public ()
-		&& field.get_field_name ().as_string ().at (0) != '_')
-	      {
-		rust_warning_at (field.get_locus (), 0,
-				 "field is never read: %qs",
-				 field.get_field_name ().as_string ().c_str ());
-	      }
+	    if (should_warn (field_hir_id, field.get_field_name (),
+			     field.get_visibility ()))
+	      rust_warning_at (field.get_locus (), 0,
+			       "field is never read: %qs",
+			       field.get_field_name ().as_string ().c_str ());
 	  }
       }
   }
 
-  void visit (HIR::TupleStruct &stct) override
+  void visit (HIR::TupleStruct &strukt) override
   {
     // only warn tuple struct unconstructed, and ignoring unused field
-    HirId hirId = stct.get_mappings ().get_hirid ();
-    if (should_warn (hirId) && !stct.get_visibility ().is_public ())
-      {
-	rust_warning_at (stct.get_locus (), 0,
-			 "struct is never constructed: %qs",
-			 stct.get_identifier ().as_string ().c_str ());
-      }
+    HirId hirId = strukt.get_mappings ().get_hirid ();
+    if (should_warn (hirId, strukt.get_identifier (), strukt.get_visibility ()))
+      rust_warning_at (strukt.get_locus (), 0,
+		       "struct is never constructed: %qs",
+		       strukt.get_identifier ().as_string ().c_str ());
+  }
+
+  void visit (HIR::Enum &enm) override
+  {
+    HirId hirId = enm.get_mappings ().get_hirid ();
+    if (should_warn (hirId, enm.get_identifier (), enm.get_visibility ()))
+      rust_warning_at (enm.get_locus (), 0, "enum is never used: %qs",
+		       enm.get_identifier ().as_string ().c_str ());
   }
 
   void visit (HIR::ImplBlock &blc) override
@@ -145,11 +152,16 @@ class ScanDeadcode : public MarkLiveBase
     : live_symbols (live_symbols), resolver (Resolver::Resolver::get ()),
       mappings (Analysis::Mappings::get ()){};
 
-  bool should_warn (HirId hirId)
+  bool should_warn (HirId hir_id, const Identifier &identifier,
+		    HIR::Visibility visibility)
   {
-    // TODO: There are more condition to check if should warn, i.e visibility,
-    // attributes.
-    return live_symbols.find (hirId) == live_symbols.end ();
+    if (name_starts_with_underscore (identifier))
+      return false;
+
+    if (visibility.is_public ())
+      return false;
+
+    return live_symbols.find (hir_id) == live_symbols.end ();
   }
 };
 

gcc/testsuite/rust/compile/derive-debug1.rs

@@ -1,6 +1,5 @@
 #![feature(no_core)]
 #![no_core]
-
 #![feature(lang_items)]
 #[lang = "sized"]
 trait Sized {}
@@ -29,17 +28,20 @@ mod core {
 
 #[derive(Debug)]
 // { dg-warning "stub implementation" "" { target *-*-* } .-1 }
-struct Foo { a: i32, b: i64 } // { dg-warning "is never constructed" }
+struct Foo {
+    // { dg-warning "is never constructed" "" { target *-*-* } .-1 }
+    a: i32,
+    b: i64,
+}
 
 #[derive(Debug)]
 // { dg-warning "stub implementation" "" { target *-*-* } .-1 }
 struct Bar(i32, i32); // { dg-warning "is never constructed" }
 
 #[derive(Debug)]
 // { dg-warning "stub implementation" "" { target *-*-* } .-1 }
-enum Baz {
+pub enum Baz {
     A,
     B(i32),
-    C { a: i32 }
+    C { a: i32 },
 }
-

gcc/testsuite/rust/compile/derive-hash1.rs

@@ -88,8 +88,8 @@ struct Foo { // { dg-warning "never constructed" }
 struct Bar(i32, i64); // { dg-warning "never constructed" }
 
 #[derive(Hash)]
-enum Baz {
+pub enum Baz {
     A,
     B(i32),
-    C { a: i64 }
+    C { a: i64 },
 }

gcc/testsuite/rust/compile/derive_clone_enum1.rs

@@ -1,6 +1,5 @@
 #![feature(no_core)]
 #![no_core]
-
 #![feature(lang_items)]
 
 #[lang = "clone"]
@@ -15,7 +14,7 @@ impl Clone for i32 {
 }
 
 #[derive(Clone)]
-enum AllIdentifiers {
+pub enum AllIdentifiers {
     A,
-    B
+    B,
 }

gcc/testsuite/rust/compile/derive_clone_enum2.rs

@@ -1,6 +1,5 @@
 #![feature(no_core)]
 #![no_core]
-
 #![feature(lang_items)]
 
 #[lang = "clone"]
@@ -15,7 +14,7 @@ impl Clone for i32 {
 }
 
 #[derive(Clone)]
-enum TupleEnum {
+pub enum TupleEnum {
     A(i32),
-    B(i32, i32, i32)
+    B(i32, i32, i32),
 }

gcc/testsuite/rust/compile/derive_clone_enum3.rs

@@ -1,6 +1,5 @@
 #![feature(no_core)]
 #![no_core]
-
 #![feature(lang_items)]
 
 #[lang = "clone"]
@@ -15,7 +14,7 @@ impl Clone for i32 {
 }
 
 #[derive(Clone)]
-enum StructEnum {
+pub enum StructEnum {
     A { i0: i32 },
-    B { i0: i32, i1: i32, i2: i32 }
+    B { i0: i32, i1: i32, i2: i32 },
 }

gcc/testsuite/rust/compile/enum_discriminant1.rs

@@ -1,10 +1,10 @@
 #![feature(no_core)]
 #![no_core]
 
-enum Foo {
+pub enum Foo {
     Bar = 3 + 12,
 }
 
 fn test() -> Foo { // { dg-warning "function is never used" }
     return Foo::Bar;
-}
+}

gcc/testsuite/rust/compile/for-loop1.rs

@@ -22,7 +22,7 @@ mod option {
 }
 
 mod result {
-    enum Result<T, E> {
+    pub enum Result<T, E> {
         Ok(T),
         Err(E),
     }

gcc/testsuite/rust/compile/for-loop2.rs

@@ -21,7 +21,7 @@ mod option {
 }
 
 mod result {
-    enum Result<T, E> {
+    pub enum Result<T, E> {
         Ok(T),
         Err(E),
     }

gcc/testsuite/rust/compile/glob_import_enum.rs

@@ -4,7 +4,7 @@
 use self::Ordering::*;
 use Ordering::*;
 
-enum Ordering {
+pub enum Ordering {
     A,
     B,
 }

gcc/testsuite/rust/compile/if_let_expr_simple.rs

@@ -1,12 +1,12 @@
 #![feature(no_core)]
 #![no_core]
 
-enum MyOption {
+pub enum MyOption {
     Some(i32),
     None,
 }
 
-pub fn toto(i : MyOption) -> i32 {
+pub fn toto(i: MyOption) -> i32 {
     if let MyOption::Some(v) = i {
         v
     } else {

gcc/testsuite/rust/compile/issue-3382.rs

@@ -1,12 +1,11 @@
 #![feature(no_core)]
 #![no_core]
-
 #![feature(lang_items)]
 
 #[lang = "sized"]
 trait Sized {}
 
-enum Result<T, E> {
+pub enum Result<T, E> {
     #[lang = "Ok"]
     Ok(T),
     #[lang = "Err"]

gcc/testsuite/rust/compile/issue-3550.rs

@@ -2,6 +2,6 @@
 #![no_core]
 
 #[cfg_attr(not(wrong = "32"), repr(i32))]
-enum Eu64 {
+pub enum Eu64 {
     Au64 = 0,
-}
+}

gcc/testsuite/rust/compile/issue-3597.rs

@@ -1,11 +1,11 @@
 #![feature(no_core)]
 #![no_core]
 
-enum E {
+pub enum E {
     A = {
-        enum F {  }
+        pub enum F {}
         0
-    }
+    },
 }
 
-fn main() {}
+fn main() {}

gcc/testsuite/rust/compile/issue-3605.rs

@@ -1,8 +1,8 @@
 #![feature(no_core)]
 #![no_core]
 
-enum Foo<'a> {}
+pub enum Foo<'a> {}
 
-enum Bar<'a> {
+pub enum Bar<'a> {
     in_band_def_explicit_impl(Foo<'a>),
 }

gcc/testsuite/rust/compile/issue-3651.rs

@@ -1,6 +1,6 @@
 #![feature(no_core)]
 #![no_core]
-enum E {
+pub enum E {
     A = {
         enum F {
             Ai32 = -1,
@@ -9,4 +9,4 @@ enum E {
     },
 }
 
-fn main() {}
+fn main() {}

gcc/testsuite/rust/compile/issue-3670.rs

@@ -1,8 +1,8 @@
 #![feature(no_core)]
 #![no_core]
-enum E {
+pub enum E {
     A = {
-        enum Foo {
+        pub enum Foo {
             Bar(isize),
             Baz,
         }

gcc/testsuite/rust/compile/issue-4367.rs

@@ -0,0 +1,13 @@
+#![feature(no_core)]
+#![no_core]
+
+enum Foo {
+    // { dg-warning "enum is never used" "" { target *-*-* } .-1 }
+    A,
+    B,
+}
+
+enum _Bar {
+    A,
+    B,
+}

gcc/testsuite/rust/compile/issue-850.rs

@@ -1,6 +1,5 @@
 #![feature(no_core)]
 #![no_core]
-
 #![feature(lang_items)]
 #[lang = "sized"]
 pub trait Sized {}
@@ -10,7 +9,7 @@ extern "C" {
 }
 
 mod option {
-    enum Option<T> {
+    pub enum Option<T> {
         #[lang = "None"]
         None,
         #[lang = "Some"]