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Commit | Line | Data |
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cdc7bbd5 XL |
1 | use clippy_utils::diagnostics::span_lint_and_sugg; |
2 | use clippy_utils::is_expn_of; | |
3 | use clippy_utils::source::{snippet, snippet_with_applicability}; | |
4 | use clippy_utils::ty::is_type_diagnostic_item; | |
f20569fa XL |
5 | use if_chain::if_chain; |
6 | use rustc_errors::Applicability; | |
7 | use rustc_hir as hir; | |
8 | use rustc_lint::LateContext; | |
9 | use rustc_middle::ty; | |
10 | use rustc_span::source_map::Span; | |
11 | use rustc_span::symbol::sym; | |
12 | use std::borrow::Cow; | |
13 | ||
14 | use super::EXPECT_FUN_CALL; | |
15 | ||
16 | /// Checks for the `EXPECT_FUN_CALL` lint. | |
17 | #[allow(clippy::too_many_lines)] | |
18 | pub(super) fn check(cx: &LateContext<'_>, expr: &hir::Expr<'_>, method_span: Span, name: &str, args: &[hir::Expr<'_>]) { | |
19 | // Strip `&`, `as_ref()` and `as_str()` off `arg` until we're left with either a `String` or | |
20 | // `&str` | |
21 | fn get_arg_root<'a>(cx: &LateContext<'_>, arg: &'a hir::Expr<'a>) -> &'a hir::Expr<'a> { | |
22 | let mut arg_root = arg; | |
23 | loop { | |
24 | arg_root = match &arg_root.kind { | |
25 | hir::ExprKind::AddrOf(hir::BorrowKind::Ref, _, expr) => expr, | |
26 | hir::ExprKind::MethodCall(method_name, _, call_args, _) => { | |
27 | if call_args.len() == 1 | |
28 | && (method_name.ident.name == sym::as_str || method_name.ident.name == sym!(as_ref)) | |
29 | && { | |
30 | let arg_type = cx.typeck_results().expr_ty(&call_args[0]); | |
31 | let base_type = arg_type.peel_refs(); | |
32 | *base_type.kind() == ty::Str || is_type_diagnostic_item(cx, base_type, sym::string_type) | |
33 | } | |
34 | { | |
35 | &call_args[0] | |
36 | } else { | |
37 | break; | |
38 | } | |
39 | }, | |
40 | _ => break, | |
41 | }; | |
42 | } | |
43 | arg_root | |
44 | } | |
45 | ||
46 | // Only `&'static str` or `String` can be used directly in the `panic!`. Other types should be | |
47 | // converted to string. | |
48 | fn requires_to_string(cx: &LateContext<'_>, arg: &hir::Expr<'_>) -> bool { | |
49 | let arg_ty = cx.typeck_results().expr_ty(arg); | |
50 | if is_type_diagnostic_item(cx, arg_ty, sym::string_type) { | |
51 | return false; | |
52 | } | |
53 | if let ty::Ref(_, ty, ..) = arg_ty.kind() { | |
54 | if *ty.kind() == ty::Str && can_be_static_str(cx, arg) { | |
55 | return false; | |
56 | } | |
57 | }; | |
58 | true | |
59 | } | |
60 | ||
61 | // Check if an expression could have type `&'static str`, knowing that it | |
62 | // has type `&str` for some lifetime. | |
63 | fn can_be_static_str(cx: &LateContext<'_>, arg: &hir::Expr<'_>) -> bool { | |
64 | match arg.kind { | |
65 | hir::ExprKind::Lit(_) => true, | |
66 | hir::ExprKind::Call(fun, _) => { | |
67 | if let hir::ExprKind::Path(ref p) = fun.kind { | |
68 | match cx.qpath_res(p, fun.hir_id) { | |
69 | hir::def::Res::Def(hir::def::DefKind::Fn | hir::def::DefKind::AssocFn, def_id) => matches!( | |
70 | cx.tcx.fn_sig(def_id).output().skip_binder().kind(), | |
71 | ty::Ref(ty::ReStatic, ..) | |
72 | ), | |
73 | _ => false, | |
74 | } | |
75 | } else { | |
76 | false | |
77 | } | |
78 | }, | |
79 | hir::ExprKind::MethodCall(..) => { | |
80 | cx.typeck_results() | |
81 | .type_dependent_def_id(arg.hir_id) | |
82 | .map_or(false, |method_id| { | |
83 | matches!( | |
84 | cx.tcx.fn_sig(method_id).output().skip_binder().kind(), | |
85 | ty::Ref(ty::ReStatic, ..) | |
86 | ) | |
87 | }) | |
88 | }, | |
89 | hir::ExprKind::Path(ref p) => matches!( | |
90 | cx.qpath_res(p, arg.hir_id), | |
91 | hir::def::Res::Def(hir::def::DefKind::Const | hir::def::DefKind::Static, _) | |
92 | ), | |
93 | _ => false, | |
94 | } | |
95 | } | |
96 | ||
97 | fn generate_format_arg_snippet( | |
98 | cx: &LateContext<'_>, | |
99 | a: &hir::Expr<'_>, | |
100 | applicability: &mut Applicability, | |
101 | ) -> Vec<String> { | |
102 | if_chain! { | |
cdc7bbd5 XL |
103 | if let hir::ExprKind::AddrOf(hir::BorrowKind::Ref, _, format_arg) = a.kind; |
104 | if let hir::ExprKind::Match(format_arg_expr, _, _) = format_arg.kind; | |
105 | if let hir::ExprKind::Tup(format_arg_expr_tup) = format_arg_expr.kind; | |
f20569fa XL |
106 | |
107 | then { | |
108 | format_arg_expr_tup | |
109 | .iter() | |
110 | .map(|a| snippet_with_applicability(cx, a.span, "..", applicability).into_owned()) | |
111 | .collect() | |
112 | } else { | |
113 | unreachable!() | |
114 | } | |
115 | } | |
116 | } | |
117 | ||
118 | fn is_call(node: &hir::ExprKind<'_>) -> bool { | |
119 | match node { | |
120 | hir::ExprKind::AddrOf(hir::BorrowKind::Ref, _, expr) => { | |
121 | is_call(&expr.kind) | |
122 | }, | |
123 | hir::ExprKind::Call(..) | |
124 | | hir::ExprKind::MethodCall(..) | |
125 | // These variants are debatable or require further examination | |
126 | | hir::ExprKind::If(..) | |
127 | | hir::ExprKind::Match(..) | |
128 | | hir::ExprKind::Block{ .. } => true, | |
129 | _ => false, | |
130 | } | |
131 | } | |
132 | ||
133 | if args.len() != 2 || name != "expect" || !is_call(&args[1].kind) { | |
134 | return; | |
135 | } | |
136 | ||
137 | let receiver_type = cx.typeck_results().expr_ty_adjusted(&args[0]); | |
138 | let closure_args = if is_type_diagnostic_item(cx, receiver_type, sym::option_type) { | |
139 | "||" | |
140 | } else if is_type_diagnostic_item(cx, receiver_type, sym::result_type) { | |
141 | "|_|" | |
142 | } else { | |
143 | return; | |
144 | }; | |
145 | ||
146 | let arg_root = get_arg_root(cx, &args[1]); | |
147 | ||
148 | let span_replace_word = method_span.with_hi(expr.span.hi()); | |
149 | ||
150 | let mut applicability = Applicability::MachineApplicable; | |
151 | ||
152 | //Special handling for `format!` as arg_root | |
153 | if_chain! { | |
154 | if let hir::ExprKind::Block(block, None) = &arg_root.kind; | |
155 | if block.stmts.len() == 1; | |
156 | if let hir::StmtKind::Local(local) = &block.stmts[0].kind; | |
157 | if let Some(arg_root) = &local.init; | |
cdc7bbd5 | 158 | if let hir::ExprKind::Call(inner_fun, inner_args) = arg_root.kind; |
f20569fa XL |
159 | if is_expn_of(inner_fun.span, "format").is_some() && inner_args.len() == 1; |
160 | if let hir::ExprKind::Call(_, format_args) = &inner_args[0].kind; | |
161 | then { | |
162 | let fmt_spec = &format_args[0]; | |
163 | let fmt_args = &format_args[1]; | |
164 | ||
165 | let mut args = vec![snippet(cx, fmt_spec.span, "..").into_owned()]; | |
166 | ||
167 | args.extend(generate_format_arg_snippet(cx, fmt_args, &mut applicability)); | |
168 | ||
169 | let sugg = args.join(", "); | |
170 | ||
171 | span_lint_and_sugg( | |
172 | cx, | |
173 | EXPECT_FUN_CALL, | |
174 | span_replace_word, | |
175 | &format!("use of `{}` followed by a function call", name), | |
176 | "try this", | |
177 | format!("unwrap_or_else({} panic!({}))", closure_args, sugg), | |
178 | applicability, | |
179 | ); | |
180 | ||
181 | return; | |
182 | } | |
183 | } | |
184 | ||
185 | let mut arg_root_snippet: Cow<'_, _> = snippet_with_applicability(cx, arg_root.span, "..", &mut applicability); | |
186 | if requires_to_string(cx, arg_root) { | |
187 | arg_root_snippet.to_mut().push_str(".to_string()"); | |
188 | } | |
189 | ||
190 | span_lint_and_sugg( | |
191 | cx, | |
192 | EXPECT_FUN_CALL, | |
193 | span_replace_word, | |
194 | &format!("use of `{}` followed by a function call", name), | |
195 | "try this", | |
196 | format!( | |
197 | "unwrap_or_else({} {{ panic!(\"{{}}\", {}) }})", | |
198 | closure_args, arg_root_snippet | |
199 | ), | |
200 | applicability, | |
201 | ); | |
202 | } |