mikros/rust
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Replace match_method_chain() with method_chain_args()

Browse Source
This commit is contained in:
Devon Hollowood 2015-12-27 14:15:09 -08:00
parent f1aac931bd
commit 29b53d600f
2 changed files with 44 additions and 73 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

92
src/methods.rs
View File

@ -5,9 +5,10 @@ use rustc::middle::subst::{Subst, TypeSpace};
use std::iter;
use std::borrow::Cow;
use utils::{snippet, span_lint, span_note_and_lint, match_path, match_type, match_method_chain,
use utils::{snippet, span_lint, span_note_and_lint, match_path, match_type, method_chain_args,
walk_ptrs_ty_depth, walk_ptrs_ty};
use utils::{OPTION_PATH, RESULT_PATH, STRING_PATH};
use utils::MethodArgs;
use self::SelfKind::*;
use self::OutType::*;
@ -158,20 +159,20 @@ impl LintPass for MethodsPass {
impl LateLintPass for MethodsPass {
fn check_expr(&mut self, cx: &LateContext, expr: &Expr) {
if let ExprMethodCall(_, _, _) = expr.node {
if match_method_chain(expr, &["unwrap"]) {
lint_unwrap(cx, expr);
if let Some(arglists) = method_chain_args(expr, &["unwrap"]) {
lint_unwrap(cx, expr, arglists[0]);
}
else if match_method_chain(expr, &["to_string"]) {
lint_to_string(cx, expr);
else if let Some(arglists) = method_chain_args(expr, &["to_string"]) {
lint_to_string(cx, expr, arglists[0]);
}
else if match_method_chain(expr, &["ok", "expect"]) {
lint_ok_expect(cx, expr);
else if let Some(arglists) = method_chain_args(expr, &["ok", "expect"]) {
lint_ok_expect(cx, expr, arglists[0]);
}
else if match_method_chain(expr, &["map", "unwrap_or"]) {
lint_map_unwrap_or(cx, expr);
else if let Some(arglists) = method_chain_args(expr, &["map", "unwrap_or"]) {
lint_map_unwrap_or(cx, expr, arglists[0], arglists[1]);
}
else if match_method_chain(expr, &["map", "unwrap_or_else"]) {
lint_map_unwrap_or_else(cx, expr);
else if let Some(arglists) = method_chain_args(expr, &["map", "unwrap_or_else"]) {
lint_map_unwrap_or_else(cx, expr, arglists[0], arglists[1]);
}
}
}
@ -218,15 +219,10 @@ impl LateLintPass for MethodsPass {
}
}
#[allow(ptr_arg)] // Type of MethodArgs is potentially a Vec
/// lint use of `unwrap()` for `Option`s and `Result`s
fn lint_unwrap(cx: &LateContext, expr: &Expr) {
let args = match expr.node {
ExprMethodCall(_, _, ref args) => args,
_ => panic!("clippy methods.rs: should not have called `lint_unwrap()` on a non-matching \
expression!"),
};
let (obj_ty, _) = walk_ptrs_ty_depth(cx.tcx.expr_ty(&args[0]));
fn lint_unwrap(cx: &LateContext, expr: &Expr, unwrap_args: &MethodArgs) {
let (obj_ty, _) = walk_ptrs_ty_depth(cx.tcx.expr_ty(&unwrap_args[0]));
if match_type(cx, obj_ty, &OPTION_PATH) {
span_lint(cx, OPTION_UNWRAP_USED, expr.span,
@ -239,18 +235,13 @@ fn lint_unwrap(cx: &LateContext, expr: &Expr) {
}
}
#[allow(ptr_arg)] // Type of MethodArgs is potentially a Vec
/// lint use of `to_string()` for `&str`s and `String`s
fn lint_to_string(cx: &LateContext, expr: &Expr) {
let args = match expr.node {
ExprMethodCall(_, _, ref args) => args,
_ => panic!("clippy methods.rs: should not have called `lint_to_string()` on a \
non-matching expression!"),
};
let (obj_ty, ptr_depth) = walk_ptrs_ty_depth(cx.tcx.expr_ty(&args[0]));
fn lint_to_string(cx: &LateContext, expr: &Expr, to_string_args: &MethodArgs) {
let (obj_ty, ptr_depth) = walk_ptrs_ty_depth(cx.tcx.expr_ty(&to_string_args[0]));
if obj_ty.sty == ty::TyStr {
let mut arg_str = snippet(cx, args[0].span, "_");
let mut arg_str = snippet(cx, to_string_args[0].span, "_");
if ptr_depth > 1 {
arg_str = Cow::Owned(format!(
"({}{})",
@ -266,19 +257,9 @@ fn lint_to_string(cx: &LateContext, expr: &Expr) {
}
}
#[allow(ptr_arg)] // Type of MethodArgs is potentially a Vec
/// lint use of `ok().expect()` for `Result`s
fn lint_ok_expect(cx: &LateContext, expr: &Expr) {
let expect_args = match expr.node {
ExprMethodCall(_, _, ref expect_args) => expect_args,
_ => panic!("clippy methods.rs: Should not have called `lint_ok_expect()` on a \
non-matching expression!")
};
let ok_args = match expect_args[0].node {
ExprMethodCall(_, _, ref ok_args) => ok_args,
_ => panic!("clippy methods.rs: Should not have called `lint_ok_expect()` on a \
non-matching expression!")
};
fn lint_ok_expect(cx: &LateContext, expr: &Expr, ok_args: &MethodArgs) {
// lint if the caller of `ok()` is a `Result`
if match_type(cx, cx.tcx.expr_ty(&ok_args[0]), &RESULT_PATH) {
let result_type = cx.tcx.expr_ty(&ok_args[0]);
@ -292,19 +273,10 @@ fn lint_ok_expect(cx: &LateContext, expr: &Expr) {
}
}
#[allow(ptr_arg)] // Type of MethodArgs is potentially a Vec
/// lint use of `map().unwrap_or()` for `Option`s
fn lint_map_unwrap_or(cx: &LateContext, expr: &Expr) {
let unwrap_args = match expr.node {
ExprMethodCall(_, _, ref unwrap_args) => unwrap_args,
_ => panic!("clippy methods.rs: Should not have called `lint_map_unwrap_or()` on a \
non-matching expression!")
};
let map_args = match unwrap_args[0].node {
ExprMethodCall(_, _, ref map_args) => map_args,
_ => panic!("clippy methods.rs: Should not have called `lint_map_unwrap_or()` on a \
non-matching expression!")
};
fn lint_map_unwrap_or(cx: &LateContext, expr: &Expr, unwrap_args: &MethodArgs,
map_args: &MethodArgs) {
// lint if the caller of `map()` is an `Option`
if match_type(cx, cx.tcx.expr_ty(&map_args[0]), &OPTION_PATH) {
// lint message
@ -330,19 +302,11 @@ fn lint_map_unwrap_or(cx: &LateContext, expr: &Expr) {
}
}
#[allow(ptr_arg)] // Type of MethodArgs is potentially a Vec
/// lint use of `map().unwrap_or_else()` for `Option`s
fn lint_map_unwrap_or_else(cx: &LateContext, expr: &Expr) {
let unwrap_args = match expr.node {
ExprMethodCall(_, _, ref unwrap_args) => unwrap_args,
_ => panic!("clippy methods.rs: Should not have called `lint_map_unwrap_or_else()` on a \
non-matching expression!")
};
let map_args = match unwrap_args[0].node {
ExprMethodCall(_, _, ref map_args) => map_args,
_ => panic!("clippy methods.rs: Should not have called `lint_map_unwrap_or_else()` on a \
non-matching expression!")
};
fn lint_map_unwrap_or_else(cx: &LateContext, expr: &Expr, unwrap_args: &MethodArgs,
map_args: &MethodArgs) {
// lint if the caller of `map()` is an `Option`
if match_type(cx, cx.tcx.expr_ty(&map_args[0]), &OPTION_PATH) {
// lint message
let msg = "called `map(f).unwrap_or_else(g)` on an Option value. This can be done more \

25
src/utils.rs
View File

@ -8,10 +8,13 @@ use rustc::middle::ty;
use std::borrow::Cow;
use syntax::ast::Lit_::*;
use syntax::ast;
use syntax::ptr::P;
use rustc::session::Session;
use std::str::FromStr;
pub type MethodArgs = HirVec<P<Expr>>;
// module DefPaths for certain structs/enums we check for
pub const OPTION_PATH: [&'static str; 3] = ["core", "option", "Option"];
pub const RESULT_PATH: [&'static str; 3] = ["core", "result", "Result"];
@ -164,24 +167,28 @@ pub fn match_path_ast(path: &ast::Path, segments: &[&str]) -> bool {
|(a, b)| a.identifier.name.as_str() == *b)
}
/// match an Expr against a chain of methods. For example, if `expr` represents the `.baz()` in
/// `foo.bar().baz()`, `matched_method_chain(expr, &["bar", "baz"])` will return true.
pub fn match_method_chain(expr: &Expr, methods: &[&str]) -> bool {
let mut current = &expr.node ;
/// match an Expr against a chain of methods, and return the matched Exprs. For example, if `expr`
/// represents the `.baz()` in `foo.bar().baz()`, `matched_method_chain(expr, &["bar", "baz"])`
/// will return a Vec containing the Exprs for `.bar()` and `.baz()`
pub fn method_chain_args<'a>(expr: &'a Expr, methods: &[&str]) -> Option<Vec<&'a MethodArgs>> {
let mut current = expr;
let mut matched = Vec::with_capacity(methods.len());
for method_name in methods.iter().rev() { // method chains are stored last -> first
if let ExprMethodCall(ref name, _, ref args) = *current {
if let ExprMethodCall(ref name, _, ref args) = current.node {
if name.node.as_str() == *method_name {
current = &args[0].node
matched.push(args); // build up `matched` backwards
current = &args[0] // go to parent expression
}
else {
return false;
return None;
}
}
else {
return false;
return None;
}
}
true
matched.reverse(); // reverse `matched`, so that it is in the same order as `methods`
Some(matched)
}