gccrs: refactor dead code lint

This patch is simple, it only moves the check of unused static items
and unused const items into the dead-code scan visitor.

gcc/rust/ChangeLog:

	* checks/lints/rust-lint-scan-deadcode.h: Warns if there is an
	unused static item or unused const item.
	* checks/lints/unused/rust-unused-checker.cc (UnusedChecker::visit):
	Removes static item and const item.
	* checks/lints/unused/rust-unused-checker.h:
	Same here.

gcc/testsuite/ChangeLog:

	* rust/compile/static_item_0.rs: Change warning description.
	* rust/compile/const_item_0.rs: New test.

Signed-off-by: Lucas Ly Ba <[email protected]>

Author: lucasly-ba

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

@@ -133,6 +133,28 @@ class ScanDeadcode : public MarkLiveBase
       item->accept_vis (*this);
   }
 
+  void visit (HIR::ConstantItem &item) override
+  {
+    std::string var_name = item.get_identifier ().as_string ();
+    bool starts_with_under_score = var_name.at (0) == '_';
+    HirId hirId = item.get_mappings ().get_hirid ();
+    if (should_warn (hirId) && !starts_with_under_score)
+      rust_warning_at (item.get_locus (), OPT_Wunused_variable,
+		       "deadcode const item %qs",
+		       item.get_identifier ().as_string ().c_str ());
+  }
+
+  void visit (HIR::StaticItem &item) override
+  {
+    std::string var_name = item.get_identifier ().as_string ();
+    bool starts_with_under_score = var_name.at (0) == '_';
+    HirId hirId = item.get_mappings ().get_hirid ();
+    if (should_warn (hirId) && !starts_with_under_score)
+      rust_warning_at (item.get_locus (), OPT_Wunused_variable,
+		       "deadcode static item %qs",
+		       item.get_identifier ().as_string ().c_str ());
+  }
+
 private:
   std::set<HirId> live_symbols;
   Resolver::Resolver *resolver;

gcc/rust/checks/lints/unused/rust-unused-checker.cc

@@ -37,35 +37,13 @@ UnusedChecker::go (HIR::Crate &crate)
   for (auto &item : crate.get_items ())
     item->accept_vis (*this);
 }
-void
-UnusedChecker::visit (HIR::ConstantItem &item)
-{
-  std::string var_name = item.get_identifier ().as_string ();
-  bool starts_with_under_score = var_name.compare (0, 1, "_") == 0;
-  auto id = item.get_mappings ().get_hirid ();
-  if (!unused_context.is_variable_used (id) && !starts_with_under_score)
-    rust_warning_at (item.get_locus (), OPT_Wunused_variable,
-		     "unused variable %qs",
-		     item.get_identifier ().as_string ().c_str ());
-}
-
-void
-UnusedChecker::visit (HIR::StaticItem &item)
-{
-  std::string var_name = item.get_identifier ().as_string ();
-  bool starts_with_under_score = var_name.compare (0, 1, "_") == 0;
-  auto id = item.get_mappings ().get_hirid ();
-  if (!unused_context.is_variable_used (id) && !starts_with_under_score)
-    rust_warning_at (item.get_locus (), OPT_Wunused_variable,
-		     "unused variable %qs",
-		     item.get_identifier ().as_string ().c_str ());
-}
 
 void
 UnusedChecker::visit (HIR::TraitItemFunc &item)
 {
   // TODO: check trait item functions if they are not derived.
 }
+
 void
 UnusedChecker::visit (HIR::IdentifierPattern &pattern)
 {

gcc/rust/checks/lints/unused/rust-unused-checker.h

@@ -38,8 +38,6 @@ class UnusedChecker : public HIR::DefaultHIRVisitor
 
   using HIR::DefaultHIRVisitor::visit;
   virtual void visit (HIR::TraitItemFunc &decl) override;
-  virtual void visit (HIR::ConstantItem &item) override;
-  virtual void visit (HIR::StaticItem &item) override;
   virtual void visit (HIR::IdentifierPattern &identifier) override;
   virtual void visit (HIR::AssignmentExpr &identifier) override;
   virtual void visit (HIR::StructPatternFieldIdent &identifier) override;

gcc/testsuite/rust/compile/const_item_0.rs

@@ -0,0 +1,2 @@
+const TEST: usize = 1;
+// { dg-warning "deadcode const .TEST." "" { target *-*-* } .-1 }

gcc/testsuite/rust/compile/static_item_0.rs

@@ -1,3 +1,2 @@
-// { dg-additional-options "-frust-unused-check-2.0" }
 static TEST: usize = 1;
-// { dg-warning "unused variable .TEST." "" { target *-*-* } .-1 }
+// { dg-warning "deadcode static item .TEST." "" { target *-*-* } .-1 }