X-Git-Url: https://git.lizzy.rs/?a=blobdiff_plain;ds=sidebyside;f=clippy_lints%2Fsrc%2Fmap_unit_fn.rs;h=8fb41b25c737717d8daadf236be24cacc23fc44f;hb=f5831523d335bc57a6371806b2ea1978942ac490;hp=a1f4b70a4dcfd8c777439bb70eae2d72d74f0533;hpb=424a33720d61e1cdc0f8886000d4549857a6ee55;p=rust.git diff --git a/clippy_lints/src/map_unit_fn.rs b/clippy_lints/src/map_unit_fn.rs index a1f4b70a4dc..8fb41b25c73 100644 --- a/clippy_lints/src/map_unit_fn.rs +++ b/clippy_lints/src/map_unit_fn.rs @@ -1,10 +1,21 @@ -use rustc::hir; -use rustc::lint::*; -use rustc::ty; -use rustc_errors::{Applicability}; -use syntax::codemap::Span; -use crate::utils::{in_macro, iter_input_pats, match_type, method_chain_args, snippet, span_lint_and_then}; +// Copyright 2014-2018 The Rust Project Developers. See the COPYRIGHT +// file at the top-level directory of this distribution. +// +// Licensed under the Apache License, Version 2.0 or the MIT license +// , at your +// option. This file may not be copied, modified, or distributed +// except according to those terms. + +use crate::rustc::hir; +use crate::rustc::lint::{LateContext, LateLintPass, LintArray, LintPass}; +use crate::rustc::ty; +use crate::rustc::{declare_tool_lint, lint_array}; +use crate::rustc_errors::Applicability; +use crate::syntax::source_map::Span; use crate::utils::paths; +use crate::utils::{in_macro, iter_input_pats, match_type, method_chain_args, snippet, span_lint_and_then}; +use if_chain::if_chain; #[derive(Clone)] pub struct Pass; @@ -75,33 +86,32 @@ "using `result.map(f)`, where f is a function or closure that returns ()" } - impl LintPass for Pass { fn get_lints(&self) -> LintArray { lint_array!(OPTION_MAP_UNIT_FN, RESULT_MAP_UNIT_FN) } } -fn is_unit_type(ty: ty::Ty) -> bool { +fn is_unit_type(ty: ty::Ty<'_>) -> bool { match ty.sty { - ty::TyTuple(slice) => slice.is_empty(), - ty::TyNever => true, + ty::Tuple(slice) => slice.is_empty(), + ty::Never => true, _ => false, } } -fn is_unit_function(cx: &LateContext, expr: &hir::Expr) -> bool { +fn is_unit_function(cx: &LateContext<'_, '_>, expr: &hir::Expr) -> bool { let ty = cx.tables.expr_ty(expr); - if let ty::TyFnDef(id, _) = ty.sty { - if let Some(fn_type) = cx.tcx.fn_sig(id).no_late_bound_regions() { + if let ty::FnDef(id, _) = ty.sty { + if let Some(fn_type) = cx.tcx.fn_sig(id).no_bound_vars() { return is_unit_type(fn_type.output()); } } false } -fn is_unit_expression(cx: &LateContext, expr: &hir::Expr) -> bool { +fn is_unit_expression(cx: &LateContext<'_, '_>, expr: &hir::Expr) -> bool { is_unit_type(cx.tables.expr_ty(expr)) } @@ -109,18 +119,17 @@ fn is_unit_expression(cx: &LateContext, expr: &hir::Expr) -> bool { /// semicolons, which causes problems when generating a suggestion. Given an /// expression that evaluates to '()' or '!', recursively remove useless braces /// and semi-colons until is suitable for including in the suggestion template -fn reduce_unit_expression<'a>(cx: &LateContext, expr: &'a hir::Expr) -> Option { +fn reduce_unit_expression<'a>(cx: &LateContext<'_, '_>, expr: &'a hir::Expr) -> Option { if !is_unit_expression(cx, expr) { return None; } match expr.node { - hir::ExprCall(_, _) | - hir::ExprMethodCall(_, _, _) => { + hir::ExprKind::Call(_, _) | hir::ExprKind::MethodCall(_, _, _) => { // Calls can't be reduced any more Some(expr.span) }, - hir::ExprBlock(ref block, _) => { + hir::ExprKind::Block(ref block, _) => { match (&block.stmts[..], block.expr.as_ref()) { (&[], Some(inner_expr)) => { // If block only contains an expression, @@ -131,9 +140,9 @@ fn reduce_unit_expression<'a>(cx: &LateContext, expr: &'a hir::Expr) -> Option Some(d.span), - hir::StmtExpr(ref e, _) => Some(e.span), - hir::StmtSemi(_, _) => Some(inner_stmt.span), + hir::StmtKind::Decl(ref d, _) => Some(d.span), + hir::StmtKind::Expr(ref e, _) => Some(e.span), + hir::StmtKind::Semi(_, _) => Some(inner_stmt.span), } }, _ => { @@ -143,7 +152,7 @@ fn reduce_unit_expression<'a>(cx: &LateContext, expr: &'a hir::Expr) -> Option None, @@ -151,7 +160,7 @@ fn reduce_unit_expression<'a>(cx: &LateContext, expr: &'a hir::Expr) -> Option(cx: &LateContext<'a, 'tcx>, expr: &'a hir::Expr) -> Option<(&'tcx hir::Arg, &'a hir::Expr)> { - if let hir::ExprClosure(_, ref decl, inner_expr_id, _, _) = expr.node { + if let hir::ExprKind::Closure(_, ref decl, inner_expr_id, _, _) = expr.node { let body = cx.tcx.hir.body(inner_expr_id); let body_expr = &body.value; @@ -167,91 +176,92 @@ fn unit_closure<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, expr: &'a hir::Expr) -> Op None } -/// Builds a name for the let binding variable (var_arg) +/// Builds a name for the let binding variable (`var_arg`) /// /// `x.field` => `x_field` /// `y` => `_y` /// /// Anything else will return `_`. -fn let_binding_name(cx: &LateContext, var_arg: &hir::Expr) -> String { +fn let_binding_name(cx: &LateContext<'_, '_>, var_arg: &hir::Expr) -> String { match &var_arg.node { - hir::ExprField(_, _) => snippet(cx, var_arg.span, "_").replace(".", "_"), - hir::ExprPath(_) => format!("_{}", snippet(cx, var_arg.span, "")), - _ => "_".to_string() + hir::ExprKind::Field(_, _) => snippet(cx, var_arg.span, "_").replace(".", "_"), + hir::ExprKind::Path(_) => format!("_{}", snippet(cx, var_arg.span, "")), + _ => "_".to_string(), } } fn suggestion_msg(function_type: &str, map_type: &str) -> String { format!( "called `map(f)` on an {0} value where `f` is a unit {1}", - map_type, - function_type + map_type, function_type ) } -fn lint_map_unit_fn(cx: &LateContext, stmt: &hir::Stmt, expr: &hir::Expr, map_args: &[hir::Expr]) { +fn lint_map_unit_fn(cx: &LateContext<'_, '_>, stmt: &hir::Stmt, expr: &hir::Expr, map_args: &[hir::Expr]) { let var_arg = &map_args[0]; let fn_arg = &map_args[1]; - let (map_type, variant, lint) = - if match_type(cx, cx.tables.expr_ty(var_arg), &paths::OPTION) { - ("Option", "Some", OPTION_MAP_UNIT_FN) - } else if match_type(cx, cx.tables.expr_ty(var_arg), &paths::RESULT) { - ("Result", "Ok", RESULT_MAP_UNIT_FN) - } else { - return - }; + let (map_type, variant, lint) = if match_type(cx, cx.tables.expr_ty(var_arg), &paths::OPTION) { + ("Option", "Some", OPTION_MAP_UNIT_FN) + } else if match_type(cx, cx.tables.expr_ty(var_arg), &paths::RESULT) { + ("Result", "Ok", RESULT_MAP_UNIT_FN) + } else { + return; + }; if is_unit_function(cx, fn_arg) { let msg = suggestion_msg("function", map_type); - let suggestion = format!("if let {0}({1}) = {2} {{ {3}(...) }}", - variant, - let_binding_name(cx, var_arg), - snippet(cx, var_arg.span, "_"), - snippet(cx, fn_arg.span, "_")); + let suggestion = format!( + "if let {0}({1}) = {2} {{ {3}(...) }}", + variant, + let_binding_name(cx, var_arg), + snippet(cx, var_arg.span, "_"), + snippet(cx, fn_arg.span, "_") + ); span_lint_and_then(cx, lint, expr.span, &msg, |db| { - db.span_suggestion_with_applicability(stmt.span, - "try this", - suggestion, - Applicability::Unspecified); + db.span_suggestion_with_applicability(stmt.span, "try this", suggestion, Applicability::Unspecified); }); } else if let Some((binding, closure_expr)) = unit_closure(cx, fn_arg) { let msg = suggestion_msg("closure", map_type); span_lint_and_then(cx, lint, expr.span, &msg, |db| { if let Some(reduced_expr_span) = reduce_unit_expression(cx, closure_expr) { - let suggestion = format!("if let {0}({1}) = {2} {{ {3} }}", - variant, - snippet(cx, binding.pat.span, "_"), - snippet(cx, var_arg.span, "_"), - snippet(cx, reduced_expr_span, "_")); - db.span_suggestion(stmt.span, "try this", suggestion); + let suggestion = format!( + "if let {0}({1}) = {2} {{ {3} }}", + variant, + snippet(cx, binding.pat.span, "_"), + snippet(cx, var_arg.span, "_"), + snippet(cx, reduced_expr_span, "_") + ); + db.span_suggestion_with_applicability( + stmt.span, + "try this", + suggestion, + Applicability::MachineApplicable, // snippet + ); } else { - let suggestion = format!("if let {0}({1}) = {2} {{ ... }}", - variant, - snippet(cx, binding.pat.span, "_"), - snippet(cx, var_arg.span, "_")); - db.span_suggestion_with_applicability(stmt.span, - "try this", - suggestion, - Applicability::Unspecified); + let suggestion = format!( + "if let {0}({1}) = {2} {{ ... }}", + variant, + snippet(cx, binding.pat.span, "_"), + snippet(cx, var_arg.span, "_") + ); + db.span_suggestion_with_applicability(stmt.span, "try this", suggestion, Applicability::Unspecified); } }); } } impl<'a, 'tcx> LateLintPass<'a, 'tcx> for Pass { - fn check_stmt(&mut self, cx: &LateContext, stmt: &hir::Stmt) { + fn check_stmt(&mut self, cx: &LateContext<'_, '_>, stmt: &hir::Stmt) { if in_macro(stmt.span) { return; } - if let hir::StmtSemi(ref expr, _) = stmt.node { - if let hir::ExprMethodCall(_, _, _) = expr.node { - if let Some(arglists) = method_chain_args(expr, &["map"]) { - lint_map_unit_fn(cx, stmt, expr, arglists[0]); - } + if let hir::StmtKind::Semi(ref expr, _) = stmt.node { + if let Some(arglists) = method_chain_args(expr, &["map"]) { + lint_map_unit_fn(cx, stmt, expr, arglists[0]); } } }