user0/rust
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

Rustup to rustc 1.16.0-nightly (468227129 2017-01-03): Recover patterns from arguments

Browse source
This commit is contained in:
Manish Goregaokar 2017-01-04 13:46:41 -08:00
parent a262e3bb0b
commit e02fac4896
9 changed files with 46 additions and 36 deletions
Download patch file Download diff file Expand all files Collapse all files

10
clippy_lints/src/map_clone.rs
View file

@ -2,7 +2,7 @@ use rustc::lint::*;
use rustc::hir::*;
use syntax::ast;
use utils::{is_adjusted, match_path, match_trait_method, match_type, remove_blocks, paths, snippet,
span_help_and_lint, walk_ptrs_ty, walk_ptrs_ty_depth};
span_help_and_lint, walk_ptrs_ty, walk_ptrs_ty_depth, iter_input_pats};
/// **What it does:** Checks for mapping `clone()` over an iterator.
///
@ -31,18 +31,20 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for Pass {
if &*name.node.as_str() == "map" && args.len() == 2 {
match args[1].node {
ExprClosure(_, ref decl, closure_eid, _) => {
let closure_expr = remove_blocks(&cx.tcx.map.body(closure_eid).value);
let body = cx.tcx.map.body(closure_eid);
let closure_expr = remove_blocks(&body.value);
if_let_chain! {[
// nothing special in the argument, besides reference bindings
// (e.g. .map(|&x| x) )
let Some(arg_ident) = get_arg_name(&*decl.inputs[0]),
let Some(first_arg) = iter_input_pats(decl, body).next(),
let Some(arg_ident) = get_arg_name(&first_arg.pat),
// the method is being called on a known type (option or iterator)
let Some(type_name) = get_type_name(cx, expr, &args[0])
], {
// look for derefs, for .map(|x| *x)
if only_derefs(cx, &*closure_expr, arg_ident) &&
// .cloned() only removes one level of indirection, don't lint on more
walk_ptrs_ty_depth(cx.tcx.tables().pat_ty(&*decl.inputs[0])).1 == 1
walk_ptrs_ty_depth(cx.tcx.tables().pat_ty(&first_arg.pat)).1 == 1
{
span_help_and_lint(cx, MAP_CLONE, expr.span, &format!(
"you seem to be using .map() to clone the contents of an {}, consider \