//! 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, Expr_, QPath, Ty_, Pat, PatKind, BindingAnnotation, StmtSemi, StmtExpr, StmtDecl, Decl_, Stmt}; use rustc::hir::intravisit::{NestedVisitorMap, Visitor}; use syntax::ast::{self, Attribute, LitKind, DUMMY_NODE_ID}; use std::collections::HashMap; /// **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 test --test compile-test` will produce /// a `./tests/ui/new_lint.stdout` file with the generated code: /// /// ```rust /// // ./tests/ui/new_lint.stdout /// if_chain!{ /// if let Expr_::ExprIf(ref cond, ref then, None) = item.node, /// if let Expr_::ExprBinary(BinOp::Eq, ref left, ref right) = cond.node, /// if let Expr_::ExprPath(ref path) = left.node, /// if let Expr_::ExprLit(ref lit) = right.node, /// if let LitKind::Int(42, _) = lit.node, /// then { /// // report your lint here /// } /// } /// ``` declare_clippy_lint! { pub LINT_AUTHOR, internal_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_chain! {{"); } fn done() { println!(" then {{"); println!(" // report your lint here"); println!(" }}"); 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 { 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() }, } } 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: 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!(" if 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!(" if {}.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!(" if {}.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!(" if 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!(" if let LitKind::Bool({:?}) = {}.node;", val, lit_pat), LitKind::Char(c) => println!(" if let LitKind::Char({:?}) = {}.node;", c, 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()) }, } }, Expr_::ExprCast(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 Ty_::TyPath(ref qp) = ty.node { println!(" if let Ty_::TyPath(ref {}) = {}.node;", qp_label, cast_ty); self.current = qp_label; self.print_qpath(qp); } 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); }, Expr_::ExprWhile(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); }, Expr_::ExprLoop(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); }, Expr_::ExprMatch(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); self.current = guard_pat; self.visit_expr(guard); } 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); } } }, 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_::ExprYield(ref sub) => { let sub_pat = self.next("sub"); println!("Yield(ref sub) = {};", current); self.current = sub_pat; self.visit_expr(sub); }, 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!(" if 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!(" if {}.node.as_str() == {:?}", field_name_pat, field_name.node.as_str()); 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.print_qpath(path); }, 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"); 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) 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_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, _, name, 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, name.node.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 Stmt_::"); let current = format!("{}.node", self.current); match s.node { // Could be an item or a local (let) binding: StmtDecl(ref decl, _) => { let decl_pat = self.next("decl"); println!("StmtDecl(ref {}, _) = {}", decl_pat, current); print!(" if let Decl_::"); let current = format!("{}.node", decl_pat); match decl.node { // A local (let) binding: Decl_::DeclLocal(ref local) => { let local_pat = self.next("local"); println!("DeclLocal(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: Decl_::DeclItem(_) => { println!("DeclItem(item_id) = {};", current); }, } } // Expr without trailing semi-colon (must have unit type): StmtExpr(ref e, _) => { let e_pat = self.next("e"); println!("StmtExpr(ref {}, _) = {}", e_pat, current); self.current = e_pat; self.visit_expr(e); }, // Expr with trailing semi-colon (may have any type): StmtSemi(ref e, _) => { let e_pat = self.next("e"); println!("StmtSemi(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(attrs: &[Attribute]) -> bool { attrs.iter().any(|attr| { attr.check_name("clippy") && 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 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), } } 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.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), }, } }