Auto merge of #31321 - jseyfried:cleanup, r=nrc

The first commit improves detection of unused imports -- it should have been part of #30325. Right now, the unused import in the changed test would not be reported.

The rest of the commits are miscellaneous, independent clean-ups in resolve that I didn't think warranted individual PRs.

r? @nrc

Author: bors

src/librustc/middle/region.rs

@@ -20,7 +20,7 @@ use front::map as ast_map;
 use session::Session;
 use util::nodemap::{FnvHashMap, NodeMap, NodeSet};
 use middle::cstore::InlinedItem;
-use middle::ty::{self, Ty};
+use middle::ty;
 
 use std::cell::RefCell;
 use std::collections::hash_map::Entry;

src/librustc_lint/types.rs

@@ -26,7 +26,6 @@ use std::{i8, i16, i32, i64, u8, u16, u32, u64, f32, f64};
 use syntax::{abi, ast};
 use syntax::attr::{self, AttrMetaMethods};
 use syntax::codemap::{self, Span};
-use syntax::ast::{TyIs, TyUs, TyI8, TyU8, TyI16, TyU16, TyI32, TyU32, TyI64, TyU64};
 
 use rustc_front::hir;
 use rustc_front::intravisit::{self, Visitor};

src/librustc_resolve/build_reduced_graph.rs

@@ -142,29 +142,17 @@ impl<'a, 'b:'a, 'tcx:'b> GraphBuilder<'a, 'b, 'tcx> {
     }
 
     fn block_needs_anonymous_module(&mut self, block: &Block) -> bool {
-        // Check each statement.
-        for statement in &block.stmts {
-            match statement.node {
-                StmtDecl(ref declaration, _) => {
-                    match declaration.node {
-                        DeclItem(_) => {
-                            return true;
-                        }
-                        _ => {
-                            // Keep searching.
-                        }
-                    }
-                }
-                _ => {
-                    // Keep searching.
+        fn is_item(statement: &hir::Stmt) -> bool {
+            if let StmtDecl(ref declaration, _) = statement.node {
+                if let DeclItem(_) = declaration.node {
+                    return true;
                 }
             }
+            false
         }
 
-        // If we found no items, we don't need to create
-        // an anonymous module.
-
-        return false;
+        // If any statements are items, we need to create an anonymous module
+        block.stmts.iter().any(is_item)
     }
 
     /// Constructs the reduced graph for one item.
@@ -309,7 +297,7 @@ impl<'a, 'b:'a, 'tcx:'b> GraphBuilder<'a, 'b, 'tcx> {
                     let external_module = self.new_extern_crate_module(parent_link, def);
                     self.define(parent, name, TypeNS, (external_module, sp));
 
-                    self.build_reduced_graph_for_external_crate(&external_module);
+                    self.build_reduced_graph_for_external_crate(external_module);
                 }
                 parent
             }
@@ -365,7 +353,7 @@ impl<'a, 'b:'a, 'tcx:'b> GraphBuilder<'a, 'b, 'tcx> {
                 for variant in &(*enum_definition).variants {
                     let item_def_id = self.ast_map.local_def_id(item.id);
                     self.build_reduced_graph_for_variant(variant, item_def_id,
-                                                         &module, variant_modifiers);
+                                                         module, variant_modifiers);
                 }
                 parent
             }
@@ -421,7 +409,7 @@ impl<'a, 'b:'a, 'tcx:'b> GraphBuilder<'a, 'b, 'tcx> {
                     };
 
                     let modifiers = DefModifiers::PUBLIC; // NB: not DefModifiers::IMPORTABLE
-                    self.define(&module_parent, item.name, ns, (def, item.span, modifiers));
+                    self.define(module_parent, item.name, ns, (def, item.span, modifiers));
 
                     self.trait_item_map.insert((item.name, def_id), item_def_id);
                 }