rust/clippy_lints/src/utils/author.rs

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//! A group of attributes that can be attached to Rust code in order
//! to generate a clippy lint detecting said code automatically.
#![allow(print_stdout, use_debug)]
use rustc::lint::*;
use rustc::hir;
use rustc::hir::{Expr, QPath, Expr_};
use rustc::hir::intravisit::{Visitor, NestedVisitorMap};
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use syntax::ast::{self, Attribute, NodeId, LitKind, DUMMY_NODE_ID};
use syntax::codemap::Span;
use std::collections::HashMap;
/// **What it does:** Generates clippy code that detects the offending pattern
///
/// **Example:**
/// ```rust
/// fn foo() {
/// // detect the following pattern
/// #[clippy(author)]
/// if x == 42 {
/// // but ignore everything from here on
/// #![clippy(author = "ignore")]
/// }
/// }
/// ```
///
/// prints
///
/// ```
/// if_let_chain!{[
/// let Expr_::ExprIf(ref cond, ref then, None) = item.node,
/// let Expr_::ExprBinary(BinOp::Eq, ref left, ref right) = cond.node,
/// let Expr_::ExprPath(ref path) = left.node,
/// let Expr_::ExprLit(ref lit) = right.node,
/// let LitKind::Int(42, _) = lit.node,
/// ], {
/// // report your lint here
/// }}
/// ```
declare_lint! {
pub LINT_AUTHOR,
Warn,
"helper for writing lints"
}
pub struct Pass;
impl LintPass for Pass {
fn get_lints(&self) -> LintArray {
lint_array!(LINT_AUTHOR)
}
}
fn prelude() {
println!("if_let_chain!{{[");
}
fn done() {
println!("], {{");
println!(" // report your lint here");
println!("}}}}");
}
impl<'a, 'tcx> LateLintPass<'a, 'tcx> for Pass {
fn check_item(&mut self, _cx: &LateContext<'a, 'tcx>, item: &'tcx hir::Item) {
if !has_attr(&item.attrs) {
return;
}
prelude();
PrintVisitor::new("item").visit_item(item);
done();
}
fn check_impl_item(&mut self, _cx: &LateContext<'a, 'tcx>, item: &'tcx hir::ImplItem) {
if !has_attr(&item.attrs) {
return;
}
prelude();
PrintVisitor::new("item").visit_impl_item(item);
done();
}
fn check_trait_item(&mut self, _cx: &LateContext<'a, 'tcx>, item: &'tcx hir::TraitItem) {
if !has_attr(&item.attrs) {
return;
}
prelude();
PrintVisitor::new("item").visit_trait_item(item);
done();
}
fn check_variant(&mut self, _cx: &LateContext<'a, 'tcx>, var: &'tcx hir::Variant, generics: &hir::Generics) {
if !has_attr(&var.node.attrs) {
return;
}
prelude();
PrintVisitor::new("var").visit_variant(var, generics, DUMMY_NODE_ID);
done();
}
fn check_struct_field(&mut self, _cx: &LateContext<'a, 'tcx>, field: &'tcx hir::StructField) {
if !has_attr(&field.attrs) {
return;
}
prelude();
PrintVisitor::new("field").visit_struct_field(field);
done();
}
fn check_expr(&mut self, _cx: &LateContext<'a, 'tcx>, expr: &'tcx hir::Expr) {
if !has_attr(&expr.attrs) {
return;
}
prelude();
PrintVisitor::new("expr").visit_expr(expr);
done();
}
fn check_arm(&mut self, _cx: &LateContext<'a, 'tcx>, arm: &'tcx hir::Arm) {
if !has_attr(&arm.attrs) {
return;
}
prelude();
PrintVisitor::new("arm").visit_arm(arm);
done();
}
fn check_stmt(&mut self, _cx: &LateContext<'a, 'tcx>, stmt: &'tcx hir::Stmt) {
if !has_attr(stmt.node.attrs()) {
return;
}
prelude();
PrintVisitor::new("stmt").visit_stmt(stmt);
done();
}
fn check_foreign_item(&mut self, _cx: &LateContext<'a, 'tcx>, item: &'tcx hir::ForeignItem) {
if !has_attr(&item.attrs) {
return;
}
prelude();
PrintVisitor::new("item").visit_foreign_item(item);
done();
}
}
impl PrintVisitor {
fn new(s: &'static str) -> Self {
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Self {
ids: HashMap::new(),
current: s.to_owned(),
}
}
fn next(&mut self, s: &'static str) -> String {
use std::collections::hash_map::Entry::*;
match self.ids.entry(s) {
// already there: start numbering from `1`
Occupied(mut occ) => {
let val = occ.get_mut();
*val += 1;
format!("{}{}", s, *val)
},
// not there: insert and return name as given
Vacant(vac) => {
vac.insert(0);
s.to_owned()
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},
}
}
}
struct PrintVisitor {
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/// Fields are the current index that needs to be appended to pattern
/// binding names
ids: HashMap<&'static str, usize>,
/// the name that needs to be destructured
current: String,
}
impl<'tcx> Visitor<'tcx> for PrintVisitor {
fn visit_expr(&mut self, expr: &Expr) {
print!(" let Expr_::Expr");
let current = format!("{}.node", self.current);
match expr.node {
Expr_::ExprBox(ref inner) => {
let inner_pat = self.next("inner");
println!("Box(ref {}) = {},", inner_pat, current);
self.current = inner_pat;
self.visit_expr(inner);
},
Expr_::ExprArray(ref elements) => {
let elements_pat = self.next("elements");
println!("Array(ref {}) = {},", elements_pat, current);
println!(" {}.len() == {},", elements_pat, elements.len());
for (i, element) in elements.iter().enumerate() {
self.current = format!("{}[{}]", elements_pat, i);
self.visit_expr(element);
}
},
Expr_::ExprCall(ref _func, ref _args) => {
println!("Call(ref func, ref args) = {},", current);
println!(" // unimplemented: `ExprCall` is not further destructured at the moment");
},
Expr_::ExprMethodCall(ref _method_name, ref _generics, ref _args) => {
println!("MethodCall(ref method_name, ref generics, ref args) = {},", current);
println!(" // unimplemented: `ExprMethodCall` is not further destructured at the moment");
},
Expr_::ExprTup(ref elements) => {
let elements_pat = self.next("elements");
println!("Tup(ref {}) = {},", elements_pat, current);
println!(" {}.len() == {},", elements_pat, elements.len());
for (i, element) in elements.iter().enumerate() {
self.current = format!("{}[{}]", elements_pat, i);
self.visit_expr(element);
}
},
Expr_::ExprBinary(ref op, ref left, ref right) => {
let op_pat = self.next("op");
let left_pat = self.next("left");
let right_pat = self.next("right");
println!("Binary(ref {}, ref {}, ref {}) = {},", op_pat, left_pat, right_pat, current);
println!(" BinOp_::{:?} == {}.node,", op.node, op_pat);
self.current = left_pat;
self.visit_expr(left);
self.current = right_pat;
self.visit_expr(right);
},
Expr_::ExprUnary(ref op, ref inner) => {
let inner_pat = self.next("inner");
println!("Unary(UnOp::{:?}, ref {}) = {},", op, inner_pat, current);
self.current = inner_pat;
self.visit_expr(inner);
},
Expr_::ExprLit(ref lit) => {
let lit_pat = self.next("lit");
println!("Lit(ref {}) = {},", lit_pat, current);
match lit.node {
LitKind::Bool(val) => println!(" let LitKind::Bool({:?}) = {}.node,", val, lit_pat),
LitKind::Char(c) => println!(" let LitKind::Char({:?}) = {}.node,", c, lit_pat),
LitKind::Byte(b) => println!(" let LitKind::Byte({}) = {}.node,", b, lit_pat),
// FIXME: also check int type
LitKind::Int(i, _) => println!(" let LitKind::Int({}, _) = {}.node,", i, lit_pat),
LitKind::Float(..) => println!(" let LitKind::Float(..) = {}.node,", lit_pat),
LitKind::FloatUnsuffixed(_) => println!(" let LitKind::FloatUnsuffixed(_) = {}.node,", lit_pat),
LitKind::ByteStr(ref vec) => {
let vec_pat = self.next("vec");
println!(" let LitKind::ByteStr(ref {}) = {}.node,", vec_pat, lit_pat);
println!(" let [{:?}] = **{},", vec, vec_pat);
},
LitKind::Str(ref text, _) => {
let str_pat = self.next("s");
println!(" let LitKind::Str(ref {}) = {}.node,", str_pat, lit_pat);
println!(" {}.as_str() == {:?}", str_pat, &*text.as_str())
},
}
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},
Expr_::ExprCast(ref expr, ref _ty) => {
let cast_pat = self.next("expr");
println!("Cast(ref {}, _) = {},", cast_pat, current);
self.current = cast_pat;
self.visit_expr(expr);
},
Expr_::ExprType(ref expr, ref _ty) => {
let cast_pat = self.next("expr");
println!("Type(ref {}, _) = {},", cast_pat, current);
self.current = cast_pat;
self.visit_expr(expr);
},
Expr_::ExprIf(ref cond, ref then, ref opt_else) => {
let cond_pat = self.next("cond");
let then_pat = self.next("then");
if let Some(ref else_) = *opt_else {
let else_pat = self.next("else_");
println!("If(ref {}, ref {}, Some(ref {})) = {},", cond_pat, then_pat, else_pat, current);
self.current = else_pat;
self.visit_expr(else_);
} else {
println!("If(ref {}, ref {}, None) = {},", cond_pat, then_pat, current);
}
self.current = cond_pat;
self.visit_expr(cond);
self.current = then_pat;
self.visit_expr(then);
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},
Expr_::ExprWhile(ref _cond, ref _body, ref _opt_label) => {
println!("While(ref cond, ref body, ref opt_label) = {},", current);
println!(" // unimplemented: `ExprWhile` is not further destructured at the moment");
},
Expr_::ExprLoop(ref _body, ref _opt_label, ref _desuraging) => {
println!("Loop(ref body, ref opt_label, ref desugaring) = {},", current);
println!(" // unimplemented: `ExprLoop` is not further destructured at the moment");
},
Expr_::ExprMatch(ref _expr, ref _arms, ref _desugaring) => {
println!("Match(ref expr, ref arms, ref desugaring) = {},", current);
println!(" // unimplemented: `ExprMatch` is not further destructured at the moment");
},
Expr_::ExprClosure(ref _capture_clause, ref _func, _, _) => {
println!("Closure(ref capture_clause, ref func, _, _) = {},", current);
println!(" // unimplemented: `ExprClosure` is not further destructured at the moment");
},
Expr_::ExprBlock(ref block) => {
let block_pat = self.next("block");
println!("Block(ref {}) = {},", block_pat, current);
self.current = block_pat;
self.visit_block(block);
},
Expr_::ExprAssign(ref target, ref value) => {
let target_pat = self.next("target");
let value_pat = self.next("value");
println!("Assign(ref {}, ref {}) = {},", target_pat, value_pat, current);
self.current = target_pat;
self.visit_expr(target);
self.current = value_pat;
self.visit_expr(value);
},
Expr_::ExprAssignOp(ref op, ref target, ref value) => {
let op_pat = self.next("op");
let target_pat = self.next("target");
let value_pat = self.next("value");
println!("AssignOp(ref {}, ref {}, ref {}) = {},", op_pat, target_pat, value_pat, current);
println!(" BinOp_::{:?} == {}.node,", op.node, op_pat);
self.current = target_pat;
self.visit_expr(target);
self.current = value_pat;
self.visit_expr(value);
},
Expr_::ExprField(ref object, ref field_name) => {
let obj_pat = self.next("object");
let field_name_pat = self.next("field_name");
println!("Field(ref {}, ref {}) = {},", obj_pat, field_name_pat, current);
println!(" {}.node.as_str() == {:?}", field_name_pat, field_name.node.as_str());
self.current = obj_pat;
self.visit_expr(object);
},
Expr_::ExprTupField(ref object, ref field_id) => {
let obj_pat = self.next("object");
let field_id_pat = self.next("field_id");
println!("TupField(ref {}, ref {}) = {},", obj_pat, field_id_pat, current);
println!(" {}.node == {}", field_id_pat, field_id.node);
self.current = obj_pat;
self.visit_expr(object);
},
Expr_::ExprIndex(ref object, ref index) => {
let object_pat = self.next("object");
let index_pat = self.next("index");
println!("Index(ref {}, ref {}) = {},", object_pat, index_pat, current);
self.current = object_pat;
self.visit_expr(object);
self.current = index_pat;
self.visit_expr(index);
},
Expr_::ExprPath(ref path) => {
let path_pat = self.next("path");
println!("Path(ref {}) = {},", path_pat, current);
self.current = path_pat;
self.visit_qpath(path, expr.id, expr.span);
},
Expr_::ExprAddrOf(mutability, ref inner) => {
let inner_pat = self.next("inner");
println!("AddrOf({:?}, ref {}) = {},", mutability, inner_pat, current);
self.current = inner_pat;
self.visit_expr(inner);
},
Expr_::ExprBreak(ref _destination, ref opt_value) => {
let destination_pat = self.next("destination");
if let Some(ref value) = *opt_value {
let value_pat = self.next("value");
println!("Break(ref {}, Some(ref {})) = {},", destination_pat, value_pat, current);
self.current = value_pat;
self.visit_expr(value);
} else {
println!("Break(ref {}, None) = {},", destination_pat, current);
}
// FIXME: implement label printing
},
Expr_::ExprAgain(ref _destination) => {
let destination_pat = self.next("destination");
println!("Again(ref {}) = {},", destination_pat, current);
// FIXME: implement label printing
},
Expr_::ExprRet(ref opt_value) => {
if let Some(ref value) = *opt_value {
let value_pat = self.next("value");
println!("Ret(Some(ref {})) = {},", value_pat, current);
self.current = value_pat;
self.visit_expr(value);
} else {
println!("Ret(None) = {},", current);
}
},
Expr_::ExprInlineAsm(_, ref _input, ref _output) => {
println!("InlineAsm(_, ref input, ref output) = {},", current);
println!(" // unimplemented: `ExprInlineAsm` is not further destructured at the moment");
},
Expr_::ExprStruct(ref path, ref fields, ref opt_base) => {
let path_pat = self.next("path");
let fields_pat = self.next("fields");
if let Some(ref base) = *opt_base {
let base_pat = self.next("base");
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println!(
"Struct(ref {}, ref {}, Some(ref {})) = {},",
path_pat,
fields_pat,
base_pat,
current
);
self.current = base_pat;
self.visit_expr(base);
} else {
println!("Struct(ref {}, ref {}, None) = {},", path_pat, fields_pat, current);
}
self.current = path_pat;
self.visit_qpath(path, expr.id, expr.span);
println!(" {}.len() == {},", fields_pat, fields.len());
println!(" // unimplemented: field checks");
},
// FIXME: compute length (needs type info)
Expr_::ExprRepeat(ref value, _) => {
let value_pat = self.next("value");
println!("Repeat(ref {}, _) = {},", value_pat, current);
println!("// unimplemented: repeat count check");
self.current = value_pat;
self.visit_expr(value);
},
}
}
fn visit_qpath(&mut self, path: &QPath, _: NodeId, _: Span) {
print!(" match_qpath({}, &[", self.current);
print_path(path, &mut true);
println!("]),");
}
fn nested_visit_map<'this>(&'this mut self) -> NestedVisitorMap<'this, 'tcx> {
NestedVisitorMap::None
}
}
fn has_attr(attrs: &[Attribute]) -> bool {
attrs.iter().any(|attr| {
attr.check_name("clippy") &&
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attr.meta_item_list().map_or(false, |list| {
list.len() == 1 &&
match list[0].node {
ast::NestedMetaItemKind::MetaItem(ref it) => it.name == "author",
ast::NestedMetaItemKind::Literal(_) => false,
}
})
})
}
fn print_path(path: &QPath, first: &mut bool) {
match *path {
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QPath::Resolved(_, ref path) => {
for segment in &path.segments {
if *first {
*first = false;
} else {
print!(", ");
}
print!("{:?}", segment.name.as_str());
}
},
QPath::TypeRelative(ref ty, ref segment) => {
match ty.node {
hir::Ty_::TyPath(ref inner_path) => {
print_path(inner_path, first);
if *first {
*first = false;
} else {
print!(", ");
}
print!("{:?}", segment.name.as_str());
},
ref other => print!("/* unimplemented: {:?}*/", other),
}
},
}
}