Fix 'unused_imports' warnings that started appearing in CI recently

Author: tgross35

bindgen/codegen/helpers.rs

@@ -126,7 +126,7 @@ pub(crate) mod ast_ty {
     use crate::ir::function::FunctionSig;
     use crate::ir::layout::Layout;
     use crate::ir::ty::{FloatKind, IntKind};
-    use proc_macro2::{self, TokenStream};
+    use proc_macro2::TokenStream;
     use std::str::FromStr;
 
     pub(crate) fn c_void(ctx: &BindgenContext) -> syn::Type {

bindgen/codegen/mod.rs

@@ -52,7 +52,7 @@ use crate::ir::template::{
 use crate::ir::ty::{Type, TypeKind};
 use crate::ir::var::Var;
 
-use proc_macro2::{self, Ident, Span};
+use proc_macro2::{Ident, Span};
 use quote::TokenStreamExt;
 
 use crate::{Entry, HashMap, HashSet};

bindgen/codegen/struct_layout.rs

@@ -7,7 +7,7 @@ use crate::ir::context::BindgenContext;
 use crate::ir::layout::Layout;
 use crate::ir::ty::{Type, TypeKind};
 use crate::FieldVisibilityKind;
-use proc_macro2::{self, Ident, Span};
+use proc_macro2::{Ident, Span};
 use std::cmp;
 
 const MAX_GUARANTEED_ALIGN: usize = 8;

bindgen/ir/context.rs

@@ -29,7 +29,6 @@ use quote::ToTokens;
 use std::borrow::Cow;
 use std::cell::{Cell, RefCell};
 use std::collections::{BTreeSet, HashMap as StdHashMap};
-use std::iter::IntoIterator;
 use std::mem;
 
 /// An identifier for some kind of IR item.

bindgen/ir/function.rs

@@ -9,7 +9,7 @@ use super::ty::TypeKind;
 use crate::callbacks::{ItemInfo, ItemKind};
 use crate::clang::{self, ABIKind, Attribute};
 use crate::parse::{ClangSubItemParser, ParseError, ParseResult};
-use clang_sys::{self, CXCallingConv};
+use clang_sys::CXCallingConv;
 
 use quote::TokenStreamExt;
 use std::io;