Merge pull request #3189 from eddyb/rextern

Reintroduce `extern crate` for non-Cargo dependencies.

Cargo.toml

@@ -1,3 +1,5 @@
+cargo-features = ["edition"]
+
 [package]
 name = "clippy"
 version = "0.0.212"

clippy_lints/Cargo.toml

@@ -1,3 +1,5 @@
+cargo-features = ["edition"]
+
 [package]
 name = "clippy_lints"
 # begin automatic update

clippy_lints/src/approx_const.rs

@@ -1,10 +1,10 @@
 use crate::utils::span_lint;
-use rustc::hir::*;
-use rustc::lint::{LateContext, LateLintPass, LintArray, LintPass};
-use rustc::{declare_tool_lint, lint_array};
+use crate::rustc::hir::*;
+use crate::rustc::lint::{LateContext, LateLintPass, LintArray, LintPass};
+use crate::rustc::{declare_tool_lint, lint_array};
 use std::f64::consts as f64;
-use syntax::ast::{FloatTy, Lit, LitKind};
-use syntax::symbol;
+use crate::syntax::ast::{FloatTy, Lit, LitKind};
+use crate::syntax::symbol;
 
 /// **What it does:** Checks for floating point literals that approximate
 /// constants which are defined in

clippy_lints/src/arithmetic.rs

@@ -1,8 +1,8 @@
 use crate::utils::span_lint;
-use rustc::hir;
-use rustc::lint::{LateContext, LateLintPass, LintArray, LintPass};
-use rustc::{declare_tool_lint, lint_array};
-use syntax::source_map::Span;
+use crate::rustc::hir;
+use crate::rustc::lint::{LateContext, LateLintPass, LintArray, LintPass};
+use crate::rustc::{declare_tool_lint, lint_array};
+use crate::syntax::source_map::Span;
 
 /// **What it does:** Checks for plain integer arithmetic.
 ///

clippy_lints/src/assign_ops.rs

@@ -1,11 +1,11 @@
 use crate::utils::{get_trait_def_id, implements_trait, snippet_opt, span_lint_and_then, SpanlessEq};
 use crate::utils::{higher, sugg};
-use rustc::hir;
-use rustc::hir::intravisit::{walk_expr, NestedVisitorMap, Visitor};
-use rustc::lint::{LateContext, LateLintPass, LintArray, LintPass};
-use rustc::{declare_tool_lint, lint_array};
+use crate::rustc::hir;
+use crate::rustc::hir::intravisit::{walk_expr, NestedVisitorMap, Visitor};
+use crate::rustc::lint::{LateContext, LateLintPass, LintArray, LintPass};
+use crate::rustc::{declare_tool_lint, lint_array};
 use if_chain::if_chain;
-use syntax::ast;
+use crate::syntax::ast;
 
 /// **What it does:** Checks for `a = a op b` or `a = b commutative_op a`
 /// patterns.
@@ -220,7 +220,7 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for AssignOps {
 }
 
 fn is_commutative(op: hir::BinOpKind) -> bool {
-    use rustc::hir::BinOpKind::*;
+    use crate::rustc::hir::BinOpKind::*;
     match op {
         Add | Mul | And | Or | BitXor | BitAnd | BitOr | Eq | Ne => true,
         Sub | Div | Rem | Shl | Shr | Lt | Le | Ge | Gt => false,

clippy_lints/src/attrs.rs

@@ -5,14 +5,14 @@ use crate::utils::{
     in_macro, last_line_of_span, match_def_path, opt_def_id, paths, snippet_opt, span_lint, span_lint_and_then,
     without_block_comments,
 };
-use rustc::hir::*;
-use rustc::lint::{LateContext, LateLintPass, LintArray, LintPass};
-use rustc::{declare_tool_lint, lint_array};
+use crate::rustc::hir::*;
+use crate::rustc::lint::{LateContext, LateLintPass, LintArray, LintPass};
+use crate::rustc::{declare_tool_lint, lint_array};
 use if_chain::if_chain;
-use rustc::ty::{self, TyCtxt};
+use crate::rustc::ty::{self, TyCtxt};
 use semver::Version;
-use syntax::ast::{AttrStyle, Attribute, Lit, LitKind, MetaItemKind, NestedMetaItem, NestedMetaItemKind};
-use syntax::source_map::Span;
+use crate::syntax::ast::{AttrStyle, Attribute, Lit, LitKind, MetaItemKind, NestedMetaItem, NestedMetaItemKind};
+use crate::syntax::source_map::Span;
 
 /// **What it does:** Checks for items annotated with `#[inline(always)]`,
 /// unless the annotated function is empty or simply panics.
@@ -180,10 +180,15 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for AttrPass {
                                                                 || is_word(lint, "deprecated") {
                                                 return
                                         },
-                                        ItemKind::ExternCrate(..) => if is_word(lint, "unused_imports")
-                                                                        && skip_unused_imports {
+                                        ItemKind::ExternCrate(..) => {
+                                            if is_word(lint, "unused_imports")
+                                                && skip_unused_imports {
+                                                    return
+                                            }
+                                            if is_word(lint, "unused_extern_crates") {
                                                 return
-                                        },
+                                            }
+                                        }
                                         _ => {},
                                     }
                                 }

clippy_lints/src/bit_mask.rs

@@ -1,9 +1,9 @@
-use rustc::hir::*;
-use rustc::lint::{LateContext, LateLintPass, LintArray, LintPass};
-use rustc::{declare_tool_lint, lint_array};
+use crate::rustc::hir::*;
+use crate::rustc::lint::{LateContext, LateLintPass, LintArray, LintPass};
+use crate::rustc::{declare_tool_lint, lint_array};
 use if_chain::if_chain;
-use syntax::ast::LitKind;
-use syntax::source_map::Span;
+use crate::syntax::ast::LitKind;
+use crate::syntax::source_map::Span;
 use crate::utils::{span_lint, span_lint_and_then};
 use crate::utils::sugg::Sugg;
 use crate::consts::{constant, Constant};

clippy_lints/src/blacklisted_name.rs

@@ -1,6 +1,6 @@
-use rustc::lint::{LateContext, LateLintPass, LintArray, LintPass};
-use rustc::{declare_tool_lint, lint_array};
-use rustc::hir::*;
+use crate::rustc::lint::{LateContext, LateLintPass, LintArray, LintPass};
+use crate::rustc::{declare_tool_lint, lint_array};
+use crate::rustc::hir::*;
 use crate::utils::span_lint;
 
 /// **What it does:** Checks for usage of blacklisted names for variables, such

clippy_lints/src/block_in_if_condition.rs

@@ -1,8 +1,8 @@
 use matches::matches;
-use rustc::lint::{LateContext, LateLintPass, LintArray, LintPass};
-use rustc::{declare_tool_lint, lint_array};
-use rustc::hir::*;
-use rustc::hir::intravisit::{walk_expr, NestedVisitorMap, Visitor};
+use crate::rustc::lint::{LateContext, LateLintPass, LintArray, LintPass};
+use crate::rustc::{declare_tool_lint, lint_array};
+use crate::rustc::hir::*;
+use crate::rustc::hir::intravisit::{walk_expr, NestedVisitorMap, Visitor};
 use crate::utils::*;
 
 /// **What it does:** Checks for `if` conditions that use blocks to contain an

clippy_lints/src/booleans.rs

@@ -1,10 +1,10 @@
-use rustc::lint::{LateContext, LateLintPass, LintArray, LintPass};
-use rustc::{declare_tool_lint, lint_array};
-use rustc::hir::*;
-use rustc::hir::intravisit::*;
-use syntax::ast::{LitKind, NodeId, DUMMY_NODE_ID};
-use syntax::source_map::{dummy_spanned, Span, DUMMY_SP};
-use rustc_data_structures::thin_vec::ThinVec;
+use crate::rustc::lint::{LateContext, LateLintPass, LintArray, LintPass};
+use crate::rustc::{declare_tool_lint, lint_array};
+use crate::rustc::hir::*;
+use crate::rustc::hir::intravisit::*;
+use crate::syntax::ast::{LitKind, NodeId, DUMMY_NODE_ID};
+use crate::syntax::source_map::{dummy_spanned, Span, DUMMY_SP};
+use crate::rustc_data_structures::thin_vec::ThinVec;
 use crate::utils::{in_macro, paths, match_type, snippet_opt, span_lint_and_then, SpanlessEq, get_trait_def_id, implements_trait};
 
 /// **What it does:** Checks for boolean expressions that can be written more

clippy_lints/src/bytecount.rs

@@ -1,9 +1,9 @@
-use rustc::hir::*;
-use rustc::lint::{LateContext, LateLintPass, LintArray, LintPass};
-use rustc::{declare_tool_lint, lint_array};
+use crate::rustc::hir::*;
+use crate::rustc::lint::{LateContext, LateLintPass, LintArray, LintPass};
+use crate::rustc::{declare_tool_lint, lint_array};
 use if_chain::if_chain;
-use rustc::ty;
-use syntax::ast::{Name, UintTy};
+use crate::rustc::ty;
+use crate::syntax::ast::{Name, UintTy};
 use crate::utils::{contains_name, get_pat_name, match_type, paths, single_segment_path, snippet, span_lint_and_sugg,
             walk_ptrs_ty};
 

clippy_lints/src/collapsible_if.rs

@@ -12,10 +12,10 @@
 //!
 //! This lint is **warn** by default
 
-use rustc::lint::{EarlyContext, EarlyLintPass, LintArray, LintPass};
-use rustc::{declare_tool_lint, lint_array};
+use crate::rustc::lint::{EarlyContext, EarlyLintPass, LintArray, LintPass};
+use crate::rustc::{declare_tool_lint, lint_array};
 use if_chain::if_chain;
-use syntax::ast;
+use crate::syntax::ast;
 
 use crate::utils::{in_macro, snippet_block, span_lint_and_sugg, span_lint_and_then};
 use crate::utils::sugg::Sugg;

clippy_lints/src/const_static_lifetime.rs

@@ -1,6 +1,6 @@
-use syntax::ast::*;
-use rustc::lint::{EarlyContext, EarlyLintPass, LintArray, LintPass};
-use rustc::{declare_tool_lint, lint_array};
+use crate::syntax::ast::*;
+use crate::rustc::lint::{EarlyContext, EarlyLintPass, LintArray, LintPass};
+use crate::rustc::{declare_tool_lint, lint_array};
 use crate::utils::{in_macro, snippet, span_lint_and_then};
 
 /// **What it does:** Checks for constants with an explicit `'static` lifetime.

clippy_lints/src/consts.rs

@@ -1,18 +1,18 @@
 #![allow(clippy::float_cmp)]
 
-use rustc::lint::LateContext;
-use rustc::{span_bug, bug};
-use rustc::hir::def::Def;
-use rustc::hir::*;
-use rustc::ty::{self, Ty, TyCtxt, Instance};
-use rustc::ty::subst::{Subst, Substs};
+use crate::rustc::lint::LateContext;
+use crate::rustc::{span_bug, bug};
+use crate::rustc::hir::def::Def;
+use crate::rustc::hir::*;
+use crate::rustc::ty::{self, Ty, TyCtxt, Instance};
+use crate::rustc::ty::subst::{Subst, Substs};
 use std::cmp::Ordering::{self, Equal};
 use std::cmp::PartialOrd;
 use std::hash::{Hash, Hasher};
 use std::mem;
 use std::rc::Rc;
-use syntax::ast::{FloatTy, LitKind};
-use syntax::ptr::P;
+use crate::syntax::ast::{FloatTy, LitKind};
+use crate::syntax::ptr::P;
 use crate::utils::{sext, unsext, clip};
 
 /// A `LitKind`-like enum to fold constant `Expr`s into.
@@ -139,7 +139,7 @@ impl Constant {
 
 /// parse a `LitKind` to a `Constant`
 pub fn lit_to_constant<'tcx>(lit: &LitKind, ty: Ty<'tcx>) -> Constant {
-    use syntax::ast::*;
+    use crate::syntax::ast::*;
 
     match *lit {
         LitKind::Str(ref is, _) => Constant::Str(is.to_string()),
@@ -279,7 +279,7 @@ impl<'c, 'cc> ConstEvalLateContext<'c, 'cc> {
                     instance,
                     promoted: None,
                 };
-                use rustc::mir::interpret::GlobalId;
+                use crate::rustc::mir::interpret::GlobalId;
                 let result = self.tcx.const_eval(self.param_env.and(gid)).ok()?;
                 let ret = miri_to_const(self.tcx, result);
                 if ret.is_some() {
@@ -409,7 +409,7 @@ impl<'c, 'cc> ConstEvalLateContext<'c, 'cc> {
 }
 
 pub fn miri_to_const<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, result: &ty::Const<'tcx>) -> Option<Constant> {
-    use rustc::mir::interpret::{Scalar, ScalarMaybeUndef, ConstValue};
+    use crate::rustc::mir::interpret::{Scalar, ScalarMaybeUndef, ConstValue};
     match result.val {
         ConstValue::Scalar(Scalar::Bits{ bits: b, ..}) => match result.ty.sty {
             ty::Bool => Some(Constant::Bool(b == 1)),

clippy_lints/src/copies.rs

@@ -1,12 +1,12 @@
-use rustc::lint::{LateContext, LateLintPass, LintArray, LintPass};
-use rustc::{declare_tool_lint, lint_array};
-use rustc::ty::Ty;
-use rustc::hir::*;
-use rustc_data_structures::fx::FxHashMap;
+use crate::rustc::lint::{LateContext, LateLintPass, LintArray, LintPass};
+use crate::rustc::{declare_tool_lint, lint_array};
+use crate::rustc::ty::Ty;
+use crate::rustc::hir::*;
+use crate::rustc_data_structures::fx::FxHashMap;
 use std::collections::hash_map::Entry;
 use std::hash::BuildHasherDefault;
-use syntax::symbol::LocalInternedString;
-use rustc_data_structures::small_vec::OneVector;
+use crate::syntax::symbol::LocalInternedString;
+use crate::rustc_data_structures::small_vec::OneVector;
 use crate::utils::{SpanlessEq, SpanlessHash};
 use crate::utils::{get_parent_expr, in_macro, snippet, span_lint_and_then, span_note_and_lint};
 

clippy_lints/src/copy_iterator.rs

@@ -1,7 +1,7 @@
 use crate::utils::{is_copy, match_path, paths, span_note_and_lint};
-use rustc::hir::{Item, ItemKind};
-use rustc::lint::{LateContext, LateLintPass, LintArray, LintPass};
-use rustc::{declare_tool_lint, lint_array};
+use crate::rustc::hir::{Item, ItemKind};
+use crate::rustc::lint::{LateContext, LateLintPass, LintArray, LintPass};
+use crate::rustc::{declare_tool_lint, lint_array};
 
 /// **What it does:** Checks for types that implement `Copy` as well as
 /// `Iterator`.

clippy_lints/src/cyclomatic_complexity.rs

@@ -1,13 +1,13 @@
 //! calculate cyclomatic complexity and warn about overly complex functions
 
-use rustc::cfg::CFG;
-use rustc::lint::{LateContext, LateLintPass, LintArray, LintPass, LintContext};
-use rustc::{declare_tool_lint, lint_array};
-use rustc::hir::*;
-use rustc::ty;
-use rustc::hir::intravisit::{walk_expr, NestedVisitorMap, Visitor};
-use syntax::ast::{Attribute, NodeId};
-use syntax::source_map::Span;
+use crate::rustc::cfg::CFG;
+use crate::rustc::lint::{LateContext, LateLintPass, LintArray, LintPass, LintContext};
+use crate::rustc::{declare_tool_lint, lint_array};
+use crate::rustc::hir::*;
+use crate::rustc::ty;
+use crate::rustc::hir::intravisit::{walk_expr, NestedVisitorMap, Visitor};
+use crate::syntax::ast::{Attribute, NodeId};
+use crate::syntax::source_map::Span;
 
 use crate::utils::{in_macro, is_allowed, match_type, paths, span_help_and_lint, LimitStack};
 

clippy_lints/src/default_trait_access.rs

@@ -1,8 +1,8 @@
-use rustc::hir::*;
-use rustc::lint::{LateContext, LateLintPass, LintArray, LintPass};
-use rustc::{declare_tool_lint, lint_array};
+use crate::rustc::hir::*;
+use crate::rustc::lint::{LateContext, LateLintPass, LintArray, LintPass};
+use crate::rustc::{declare_tool_lint, lint_array};
 use if_chain::if_chain;
-use rustc::ty::TyKind;
+use crate::rustc::ty::TyKind;
 
 use crate::utils::{any_parent_is_automatically_derived, match_def_path, opt_def_id, paths, span_lint_and_sugg};
 

clippy_lints/src/derive.rs

@@ -1,9 +1,9 @@
-use rustc::lint::{LateContext, LateLintPass, LintArray, LintPass};
-use rustc::{declare_tool_lint, lint_array};
+use crate::rustc::lint::{LateContext, LateLintPass, LintArray, LintPass};
+use crate::rustc::{declare_tool_lint, lint_array};
 use if_chain::if_chain;
-use rustc::ty::{self, Ty};
-use rustc::hir::*;
-use syntax::source_map::Span;
+use crate::rustc::ty::{self, Ty};
+use crate::rustc::hir::*;
+use crate::syntax::source_map::Span;
 use crate::utils::paths;
 use crate::utils::{is_automatically_derived, is_copy, match_path, span_lint_and_then};
 

clippy_lints/src/doc.rs

@@ -1,10 +1,10 @@
 use itertools::Itertools;
 use pulldown_cmark;
-use rustc::lint::{EarlyContext, EarlyLintPass, LintArray, LintPass};
-use rustc::{declare_tool_lint, lint_array};
-use syntax::ast;
-use syntax::source_map::{BytePos, Span};
-use syntax_pos::Pos;
+use crate::rustc::lint::{EarlyContext, EarlyLintPass, LintArray, LintPass};
+use crate::rustc::{declare_tool_lint, lint_array};
+use crate::syntax::ast;
+use crate::syntax::source_map::{BytePos, Span};
+use crate::syntax_pos::Pos;
 use crate::utils::span_lint;
 use url::Url;
 

clippy_lints/src/double_comparison.rs

@@ -1,9 +1,9 @@
 //! Lint on unnecessary double comparisons. Some examples:
 
-use rustc::hir::*;
-use rustc::lint::{LateContext, LateLintPass, LintArray, LintPass};
-use rustc::{declare_tool_lint, lint_array};
-use syntax::source_map::Span;
+use crate::rustc::hir::*;
+use crate::rustc::lint::{LateContext, LateLintPass, LintArray, LintPass};
+use crate::rustc::{declare_tool_lint, lint_array};
+use crate::syntax::source_map::Span;
 
 use crate::utils::{snippet, span_lint_and_sugg, SpanlessEq};
 

clippy_lints/src/double_parens.rs

@@ -1,6 +1,6 @@
-use syntax::ast::*;
-use rustc::lint::{EarlyContext, EarlyLintPass, LintArray, LintContext, LintPass};
-use rustc::{declare_tool_lint, lint_array};
+use crate::syntax::ast::*;
+use crate::rustc::lint::{EarlyContext, EarlyLintPass, LintArray, LintContext, LintPass};
+use crate::rustc::{declare_tool_lint, lint_array};
 
 /// **What it does:** Checks for unnecessary double parentheses.
 ///

clippy_lints/src/drop_forget_ref.rs

@@ -1,8 +1,8 @@
-use rustc::lint::{LateContext, LateLintPass, LintArray, LintPass};
-use rustc::{declare_tool_lint, lint_array};
+use crate::rustc::lint::{LateContext, LateLintPass, LintArray, LintPass};
+use crate::rustc::{declare_tool_lint, lint_array};
 use if_chain::if_chain;
-use rustc::ty;
-use rustc::hir::*;
+use crate::rustc::ty;
+use crate::rustc::hir::*;
 use crate::utils::{is_copy, match_def_path, opt_def_id, paths, span_note_and_lint};
 
 /// **What it does:** Checks for calls to `std::mem::drop` with a reference