//! A group of attributes that can be attached to Rust code in order //! to generate a clippy lint detecting said code automatically. use crate::utils::{get_attr, higher}; use rustc::hir; use rustc::hir::intravisit::{NestedVisitorMap, Visitor}; use rustc::hir::{BindingAnnotation, Expr, ExprKind, Pat, PatKind, QPath, Stmt, StmtKind, TyKind}; use rustc::lint::{LateContext, LateLintPass, LintArray, LintContext, LintPass}; use rustc::session::Session; use rustc::{declare_lint_pass, declare_tool_lint}; use rustc_data_structures::fx::FxHashMap; use syntax::ast::{Attribute, LitKind}; declare_clippy_lint! { /// **What it does:** Generates clippy code that detects the offending pattern /// /// **Example:** /// ```rust /// // ./tests/ui/my_lint.rs /// fn foo() { /// // detect the following pattern /// #[clippy::author] /// if x == 42 { /// // but ignore everything from here on /// #![clippy::author = "ignore"] /// } /// } /// ``` /// /// Running `TESTNAME=ui/my_lint cargo uitest` will produce /// a `./tests/ui/new_lint.stdout` file with the generated code: /// /// ```rust /// // ./tests/ui/new_lint.stdout /// if_chain! { /// if let ExprKind::If(ref cond, ref then, None) = item.node, /// if let ExprKind::Binary(BinOp::Eq, ref left, ref right) = cond.node, /// if let ExprKind::Path(ref path) = left.node, /// if let ExprKind::Lit(ref lit) = right.node, /// if let LitKind::Int(42, _) = lit.node, /// then { /// // report your lint here /// } /// } /// ``` pub LINT_AUTHOR, internal_warn, "helper for writing lints" } declare_lint_pass!(Author => [LINT_AUTHOR]); fn prelude() { println!("if_chain! {{"); } fn done() { println!(" then {{"); println!(" // report your lint here"); println!(" }}"); println!("}}"); } impl<'a, 'tcx> LateLintPass<'a, 'tcx> for Author { fn check_item(&mut self, cx: &LateContext<'a, 'tcx>, item: &'tcx hir::Item) { if !has_attr(cx.sess(), &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(cx.sess(), &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(cx.sess(), &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(cx.sess(), &var.node.attrs) { return; } prelude(); PrintVisitor::new("var").visit_variant(var, generics, hir::DUMMY_HIR_ID); done(); } fn check_struct_field(&mut self, cx: &LateContext<'a, 'tcx>, field: &'tcx hir::StructField) { if !has_attr(cx.sess(), &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(cx.sess(), &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(cx.sess(), &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(cx.sess(), 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(cx.sess(), &item.attrs) { return; } prelude(); PrintVisitor::new("item").visit_foreign_item(item); done(); } } impl PrintVisitor { fn new(s: &'static str) -> Self { Self { ids: FxHashMap::default(), 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() }, } } fn print_qpath(&mut self, path: &QPath) { print!(" if match_qpath({}, &[", self.current); print_path(path, &mut true); println!("]);"); } } struct PrintVisitor { /// Fields are the current index that needs to be appended to pattern /// binding names ids: FxHashMap<&'static str, usize>, /// the name that needs to be destructured current: String, } impl<'tcx> Visitor<'tcx> for PrintVisitor { #[allow(clippy::too_many_lines)] fn visit_expr(&mut self, expr: &Expr) { // handle if desugarings // TODO add more desugarings here if let Some((cond, then, opt_else)) = higher::if_block(&expr) { let cond_pat = self.next("cond"); let then_pat = self.next("then"); if let Some(else_) = opt_else { let else_pat = self.next("else_"); println!( " if let Some((ref {}, ref {}, Some({}))) = higher::if_block(&{});", cond_pat, then_pat, else_pat, self.current ); self.current = else_pat; self.visit_expr(else_); } else { println!( " if let Some((ref {}, ref {}, None)) = higher::if_block(&{});", cond_pat, then_pat, self.current ); } self.current = cond_pat; self.visit_expr(cond); self.current = then_pat; self.visit_expr(then); return; } print!(" if let ExprKind::"); let current = format!("{}.node", self.current); match expr.node { ExprKind::Box(ref inner) => { let inner_pat = self.next("inner"); println!("Box(ref {}) = {};", inner_pat, current); self.current = inner_pat; self.visit_expr(inner); }, ExprKind::Array(ref elements) => { let elements_pat = self.next("elements"); println!("Array(ref {}) = {};", elements_pat, current); println!(" if {}.len() == {};", elements_pat, elements.len()); for (i, element) in elements.iter().enumerate() { self.current = format!("{}[{}]", elements_pat, i); self.visit_expr(element); } }, ExprKind::Call(ref func, ref args) => { let func_pat = self.next("func"); let args_pat = self.next("args"); println!("Call(ref {}, ref {}) = {};", func_pat, args_pat, current); self.current = func_pat; self.visit_expr(func); println!(" if {}.len() == {};", args_pat, args.len()); for (i, arg) in args.iter().enumerate() { self.current = format!("{}[{}]", args_pat, i); self.visit_expr(arg); } }, ExprKind::MethodCall(ref _method_name, ref _generics, ref _args) => { println!("MethodCall(ref method_name, ref generics, ref args) = {};", current); println!(" // unimplemented: `ExprKind::MethodCall` is not further destructured at the moment"); }, ExprKind::Tup(ref elements) => { let elements_pat = self.next("elements"); println!("Tup(ref {}) = {};", elements_pat, current); println!(" if {}.len() == {};", elements_pat, elements.len()); for (i, element) in elements.iter().enumerate() { self.current = format!("{}[{}]", elements_pat, i); self.visit_expr(element); } }, ExprKind::Binary(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!(" if BinOpKind::{:?} == {}.node;", op.node, op_pat); self.current = left_pat; self.visit_expr(left); self.current = right_pat; self.visit_expr(right); }, ExprKind::Unary(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); }, ExprKind::Lit(ref lit) => { let lit_pat = self.next("lit"); println!("Lit(ref {}) = {};", lit_pat, current); match lit.node { LitKind::Bool(val) => println!(" if let LitKind::Bool({:?}) = {}.node;", val, lit_pat), LitKind::Char(c) => println!(" if let LitKind::Char({:?}) = {}.node;", c, lit_pat), LitKind::Err(val) => println!(" if let LitKind::Err({}) = {}.node;", val, lit_pat), LitKind::Byte(b) => println!(" if let LitKind::Byte({}) = {}.node;", b, lit_pat), // FIXME: also check int type LitKind::Int(i, _) => println!(" if let LitKind::Int({}, _) = {}.node;", i, lit_pat), LitKind::Float(..) => println!(" if let LitKind::Float(..) = {}.node;", lit_pat), LitKind::FloatUnsuffixed(_) => { println!(" if let LitKind::FloatUnsuffixed(_) = {}.node;", lit_pat) }, LitKind::ByteStr(ref vec) => { let vec_pat = self.next("vec"); println!(" if let LitKind::ByteStr(ref {}) = {}.node;", vec_pat, lit_pat); println!(" if let [{:?}] = **{};", vec, vec_pat); }, LitKind::Str(ref text, _) => { let str_pat = self.next("s"); println!(" if let LitKind::Str(ref {}) = {}.node;", str_pat, lit_pat); println!(" if {}.as_str() == {:?}", str_pat, &*text.as_str()) }, } }, ExprKind::Cast(ref expr, ref ty) => { let cast_pat = self.next("expr"); let cast_ty = self.next("cast_ty"); let qp_label = self.next("qp"); println!("Cast(ref {}, ref {}) = {};", cast_pat, cast_ty, current); if let TyKind::Path(ref qp) = ty.node { println!(" if let TyKind::Path(ref {}) = {}.node;", qp_label, cast_ty); self.current = qp_label; self.print_qpath(qp); } self.current = cast_pat; self.visit_expr(expr); }, ExprKind::Type(ref expr, ref _ty) => { let cast_pat = self.next("expr"); println!("Type(ref {}, _) = {};", cast_pat, current); self.current = cast_pat; self.visit_expr(expr); }, ExprKind::While(ref cond, ref body, _) => { let cond_pat = self.next("cond"); let body_pat = self.next("body"); let label_pat = self.next("label"); println!( "While(ref {}, ref {}, ref {}) = {};", cond_pat, body_pat, label_pat, current ); self.current = cond_pat; self.visit_expr(cond); self.current = body_pat; self.visit_block(body); }, ExprKind::Loop(ref body, _, desugaring) => { let body_pat = self.next("body"); let des = loop_desugaring_name(desugaring); let label_pat = self.next("label"); println!("Loop(ref {}, ref {}, {}) = {};", body_pat, label_pat, des, current); self.current = body_pat; self.visit_block(body); }, ExprKind::Match(ref expr, ref arms, desugaring) => { let des = desugaring_name(desugaring); let expr_pat = self.next("expr"); let arms_pat = self.next("arms"); println!("Match(ref {}, ref {}, {}) = {};", expr_pat, arms_pat, des, current); self.current = expr_pat; self.visit_expr(expr); println!(" if {}.len() == {};", arms_pat, arms.len()); for (i, arm) in arms.iter().enumerate() { self.current = format!("{}[{}].body", arms_pat, i); self.visit_expr(&arm.body); if let Some(ref guard) = arm.guard { let guard_pat = self.next("guard"); println!(" if let Some(ref {}) = {}[{}].guard;", guard_pat, arms_pat, i); match guard { hir::Guard::If(ref if_expr) => { let if_expr_pat = self.next("expr"); println!(" if let Guard::If(ref {}) = {};", if_expr_pat, guard_pat); self.current = if_expr_pat; self.visit_expr(if_expr); }, } } println!(" if {}[{}].pats.len() == {};", arms_pat, i, arm.pats.len()); for (j, pat) in arm.pats.iter().enumerate() { self.current = format!("{}[{}].pats[{}]", arms_pat, i, j); self.visit_pat(pat); } } }, ExprKind::Closure(ref _capture_clause, ref _func, _, _, _) => { println!("Closure(ref capture_clause, ref func, _, _, _) = {};", current); println!(" // unimplemented: `ExprKind::Closure` is not further destructured at the moment"); }, ExprKind::Yield(ref sub) => { let sub_pat = self.next("sub"); println!("Yield(ref sub) = {};", current); self.current = sub_pat; self.visit_expr(sub); }, ExprKind::Block(ref block, _) => { let block_pat = self.next("block"); println!("Block(ref {}) = {};", block_pat, current); self.current = block_pat; self.visit_block(block); }, ExprKind::Assign(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); }, ExprKind::AssignOp(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!(" if BinOpKind::{:?} == {}.node;", op.node, op_pat); self.current = target_pat; self.visit_expr(target); self.current = value_pat; self.visit_expr(value); }, ExprKind::Field(ref object, ref field_ident) => { 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!(" if {}.node.as_str() == {:?}", field_name_pat, field_ident.as_str()); self.current = obj_pat; self.visit_expr(object); }, ExprKind::Index(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); }, ExprKind::Path(ref path) => { let path_pat = self.next("path"); println!("Path(ref {}) = {};", path_pat, current); self.current = path_pat; self.print_qpath(path); }, ExprKind::AddrOf(mutability, ref inner) => { let inner_pat = self.next("inner"); println!("AddrOf({:?}, ref {}) = {};", mutability, inner_pat, current); self.current = inner_pat; self.visit_expr(inner); }, ExprKind::Break(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 }, ExprKind::Continue(ref _destination) => { let destination_pat = self.next("destination"); println!("Again(ref {}) = {};", destination_pat, current); // FIXME: implement label printing }, ExprKind::Ret(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); } }, ExprKind::InlineAsm(_, ref _input, ref _output) => { println!("InlineAsm(_, ref input, ref output) = {};", current); println!(" // unimplemented: `ExprKind::InlineAsm` is not further destructured at the moment"); }, ExprKind::Struct(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"); 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.print_qpath(path); println!(" if {}.len() == {};", fields_pat, fields.len()); println!(" // unimplemented: field checks"); }, // FIXME: compute length (needs type info) ExprKind::Repeat(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); }, ExprKind::Err => { println!("Err = {}", current); }, ExprKind::DropTemps(ref expr) => { let expr_pat = self.next("expr"); println!("DropTemps(ref {}) = {};", expr_pat, current); self.current = expr_pat; self.visit_expr(expr); }, } } #[allow(clippy::too_many_lines)] fn visit_pat(&mut self, pat: &Pat) { print!(" if let PatKind::"); let current = format!("{}.node", self.current); match pat.node { PatKind::Wild => println!("Wild = {};", current), PatKind::Binding(anno, .., ident, ref sub) => { let anno_pat = match anno { BindingAnnotation::Unannotated => "BindingAnnotation::Unannotated", BindingAnnotation::Mutable => "BindingAnnotation::Mutable", BindingAnnotation::Ref => "BindingAnnotation::Ref", BindingAnnotation::RefMut => "BindingAnnotation::RefMut", }; let name_pat = self.next("name"); if let Some(ref sub) = *sub { let sub_pat = self.next("sub"); println!( "Binding({}, _, {}, Some(ref {})) = {};", anno_pat, name_pat, sub_pat, current ); self.current = sub_pat; self.visit_pat(sub); } else { println!("Binding({}, _, {}, None) = {};", anno_pat, name_pat, current); } println!(" if {}.node.as_str() == \"{}\";", name_pat, ident.as_str()); }, PatKind::Struct(ref path, ref fields, ignore) => { let path_pat = self.next("path"); let fields_pat = self.next("fields"); println!( "Struct(ref {}, ref {}, {}) = {};", path_pat, fields_pat, ignore, current ); self.current = path_pat; self.print_qpath(path); println!(" if {}.len() == {};", fields_pat, fields.len()); println!(" // unimplemented: field checks"); }, PatKind::TupleStruct(ref path, ref fields, skip_pos) => { let path_pat = self.next("path"); let fields_pat = self.next("fields"); println!( "TupleStruct(ref {}, ref {}, {:?}) = {};", path_pat, fields_pat, skip_pos, current ); self.current = path_pat; self.print_qpath(path); println!(" if {}.len() == {};", fields_pat, fields.len()); println!(" // unimplemented: field checks"); }, PatKind::Path(ref path) => { let path_pat = self.next("path"); println!("Path(ref {}) = {};", path_pat, current); self.current = path_pat; self.print_qpath(path); }, PatKind::Tuple(ref fields, skip_pos) => { let fields_pat = self.next("fields"); println!("Tuple(ref {}, {:?}) = {};", fields_pat, skip_pos, current); println!(" if {}.len() == {};", fields_pat, fields.len()); println!(" // unimplemented: field checks"); }, PatKind::Box(ref pat) => { let pat_pat = self.next("pat"); println!("Box(ref {}) = {};", pat_pat, current); self.current = pat_pat; self.visit_pat(pat); }, PatKind::Ref(ref pat, muta) => { let pat_pat = self.next("pat"); println!("Ref(ref {}, Mutability::{:?}) = {};", pat_pat, muta, current); self.current = pat_pat; self.visit_pat(pat); }, PatKind::Lit(ref lit_expr) => { let lit_expr_pat = self.next("lit_expr"); println!("Lit(ref {}) = {}", lit_expr_pat, current); self.current = lit_expr_pat; self.visit_expr(lit_expr); }, PatKind::Range(ref start, ref end, end_kind) => { let start_pat = self.next("start"); let end_pat = self.next("end"); println!( "Range(ref {}, ref {}, RangeEnd::{:?}) = {};", start_pat, end_pat, end_kind, current ); self.current = start_pat; self.visit_expr(start); self.current = end_pat; self.visit_expr(end); }, PatKind::Slice(ref start, ref middle, ref end) => { let start_pat = self.next("start"); let end_pat = self.next("end"); if let Some(ref middle) = middle { let middle_pat = self.next("middle"); println!( "Slice(ref {}, Some(ref {}), ref {}) = {};", start_pat, middle_pat, end_pat, current ); self.current = middle_pat; self.visit_pat(middle); } else { println!("Slice(ref {}, None, ref {}) = {};", start_pat, end_pat, current); } println!(" if {}.len() == {};", start_pat, start.len()); for (i, pat) in start.iter().enumerate() { self.current = format!("{}[{}]", start_pat, i); self.visit_pat(pat); } println!(" if {}.len() == {};", end_pat, end.len()); for (i, pat) in end.iter().enumerate() { self.current = format!("{}[{}]", end_pat, i); self.visit_pat(pat); } }, } } fn visit_stmt(&mut self, s: &Stmt) { print!(" if let StmtKind::"); let current = format!("{}.node", self.current); match s.node { // A local (let) binding: StmtKind::Local(ref local) => { let local_pat = self.next("local"); println!("Local(ref {}) = {};", local_pat, current); if let Some(ref init) = local.init { let init_pat = self.next("init"); println!(" if let Some(ref {}) = {}.init;", init_pat, local_pat); self.current = init_pat; self.visit_expr(init); } self.current = format!("{}.pat", local_pat); self.visit_pat(&local.pat); }, // An item binding: StmtKind::Item(_) => { println!("Item(item_id) = {};", current); }, // Expr without trailing semi-colon (must have unit type): StmtKind::Expr(ref e) => { let e_pat = self.next("e"); println!("Expr(ref {}, _) = {}", e_pat, current); self.current = e_pat; self.visit_expr(e); }, // Expr with trailing semi-colon (may have any type): StmtKind::Semi(ref e) => { let e_pat = self.next("e"); println!("Semi(ref {}, _) = {}", e_pat, current); self.current = e_pat; self.visit_expr(e); }, } } fn nested_visit_map<'this>(&'this mut self) -> NestedVisitorMap<'this, 'tcx> { NestedVisitorMap::None } } fn has_attr(sess: &Session, attrs: &[Attribute]) -> bool { get_attr(sess, attrs, "author").count() > 0 } fn desugaring_name(des: hir::MatchSource) -> String { match des { hir::MatchSource::ForLoopDesugar => "MatchSource::ForLoopDesugar".to_string(), hir::MatchSource::TryDesugar => "MatchSource::TryDesugar".to_string(), hir::MatchSource::WhileLetDesugar => "MatchSource::WhileLetDesugar".to_string(), hir::MatchSource::Normal => "MatchSource::Normal".to_string(), hir::MatchSource::IfLetDesugar { contains_else_clause } => format!( "MatchSource::IfLetDesugar {{ contains_else_clause: {} }}", contains_else_clause ), hir::MatchSource::IfDesugar { contains_else_clause } => format!( "MatchSource::IfDesugar {{ contains_else_clause: {} }}", contains_else_clause ), hir::MatchSource::AwaitDesugar => "MatchSource::AwaitDesugar".to_string(), } } fn loop_desugaring_name(des: hir::LoopSource) -> &'static str { match des { hir::LoopSource::ForLoop => "LoopSource::ForLoop", hir::LoopSource::Loop => "LoopSource::Loop", hir::LoopSource::WhileLet => "LoopSource::WhileLet", } } fn print_path(path: &QPath, first: &mut bool) { match *path { QPath::Resolved(_, ref path) => { for segment in &path.segments { if *first { *first = false; } else { print!(", "); } print!("{:?}", segment.ident.as_str()); } }, QPath::TypeRelative(ref ty, ref segment) => match ty.node { hir::TyKind::Path(ref inner_path) => { print_path(inner_path, first); if *first { *first = false; } else { print!(", "); } print!("{:?}", segment.ident.as_str()); }, ref other => print!("/* unimplemented: {:?}*/", other), }, } }