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PyriphlegethonPyriphlegethon
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Add "nonsensical OpenOptions" lint
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‎README.md

Lines changed: 2 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -6,7 +6,7 @@ A collection of lints to catch common mistakes and improve your Rust code.
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[Jump to usage instructions](#usage)
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##Lints
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There are 59 lints included in this crate:
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There are 60 lints included in this crate:
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name | default | meaning
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-------------------------------------------------------------------------------------------------------|---------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
@@ -42,6 +42,7 @@ name
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[needless_range_loop](https://github.com/Manishearth/rust-clippy/wiki#needless_range_loop) | warn | for-looping over a range of indices where an iterator over items would do
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[needless_return](https://github.com/Manishearth/rust-clippy/wiki#needless_return) | warn | using a return statement like `return expr;` where an expression would suffice
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[non_ascii_literal](https://github.com/Manishearth/rust-clippy/wiki#non_ascii_literal) | allow | using any literal non-ASCII chars in a string literal; suggests using the \\u escape instead
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[nonsensical_open_options](https://github.com/Manishearth/rust-clippy/wiki#nonsensical_open_options) | warn | The options used for opening a file are nonsensical
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[option_unwrap_used](https://github.com/Manishearth/rust-clippy/wiki#option_unwrap_used) | allow | using `Option.unwrap()`, which should at least get a better message using `expect()`
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[precedence](https://github.com/Manishearth/rust-clippy/wiki#precedence) | warn | catches operations where precedence may be unclear. See the wiki for a list of cases caught
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[ptr_arg](https://github.com/Manishearth/rust-clippy/wiki#ptr_arg) | allow | fn arguments of the type `&Vec<...>` or `&String`, suggesting to use `&[...]` or `&str` instead, respectively

‎src/lib.rs

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Original file line numberDiff line numberDiff line change
@@ -47,6 +47,7 @@ pub mod loops;
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pub mod ranges;
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pub mod matches;
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pub mod precedence;
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pub mod open_options;
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mod reexport {
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pub use syntax::ast::{Name, Ident, NodeId};
@@ -88,6 +89,7 @@ pub fn plugin_registrar(reg: &mut Registry) {
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reg.register_late_lint_pass(box matches::MatchPass);
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reg.register_late_lint_pass(box misc::PatternPass);
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reg.register_late_lint_pass(box minmax::MinMaxPass);
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reg.register_late_lint_pass(box open_options::NonSensicalOpenOptions);
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reg.register_lint_group("clippy_pedantic", vec![
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methods::OPTION_UNWRAP_USED,
@@ -142,6 +144,7 @@ pub fn plugin_registrar(reg: &mut Registry) {
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misc::TOPLEVEL_REF_ARG,
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mut_reference::UNNECESSARY_MUT_PASSED,
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needless_bool::NEEDLESS_BOOL,
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open_options::NONSENSICAL_OPEN_OPTIONS,
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precedence::PRECEDENCE,
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ranges::RANGE_STEP_BY_ZERO,
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returns::LET_AND_RETURN,

‎src/open_options.rs

Lines changed: 139 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,139 @@
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use rustc::lint::*;
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use rustc_front::hir::{Expr, ExprMethodCall, ExprLit};
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use utils::{walk_ptrs_ty_depth, match_type, span_lint, OPEN_OPTIONS_PATH};
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use syntax::codemap::{Span, Spanned};
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use syntax::ast::Lit_::LitBool;
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declare_lint! {
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pub NONSENSICAL_OPEN_OPTIONS,
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Warn,
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"The options used for opening a file are nonsensical"
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}
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#[derive(Copy,Clone)]
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pub struct NonSensicalOpenOptions;
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impl LintPass for NonSensicalOpenOptions {
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fn get_lints(&self) -> LintArray {
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lint_array!(NONSENSICAL_OPEN_OPTIONS)
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}
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}
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impl LateLintPass for NonSensicalOpenOptions {
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fn check_expr(&mut self, cx: &LateContext, e: &Expr) {
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if let ExprMethodCall(ref name, _, ref arguments) = e.node {
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let (obj_ty, _) = walk_ptrs_ty_depth(cx.tcx.expr_ty(&arguments[0]));
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if name.node.as_str() == "open" && match_type(cx, obj_ty, &OPEN_OPTIONS_PATH){
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let mut options = Vec::new();
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get_open_options(cx, &arguments[0], &mut options);
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check_open_options(cx, &options, e.span);
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}
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}
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}
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}
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#[derive(Debug)]
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enum Argument {
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True,
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False,
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Unknown
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}
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#[derive(Debug)]
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enum OpenOption {
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Write(Argument),
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Read(Argument),
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Truncate(Argument),
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Create(Argument),
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Append(Argument)
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}
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fn get_open_options(cx: &LateContext, argument: &Expr, options: &mut Vec<OpenOption>) {
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if let ExprMethodCall(ref name, _, ref arguments) = argument.node {
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let (obj_ty, _) = walk_ptrs_ty_depth(cx.tcx.expr_ty(&arguments[0]));
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// Only proceed if this is a call on some object of type std::fs::OpenOptions
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if match_type(cx, obj_ty, &OPEN_OPTIONS_PATH) && arguments.len() >= 2 {
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let argument_option = match arguments[1].node {
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ExprLit(ref span) => {
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if let Spanned {node: LitBool(lit), span: _} = **span {
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if lit {Argument::True} else {Argument::False}
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} else {
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return; // The function is called with a literal
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// which is not a boolean literal. This is theoretically
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// possible, but not very likely.
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}
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},
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_ => {
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Argument::Unknown
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}
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};
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match &*name.node.as_str() {
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"create" => {
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options.push(OpenOption::Create(argument_option));
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},
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"append" => {
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options.push(OpenOption::Append(argument_option));
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},
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"truncate" => {
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options.push(OpenOption::Truncate(argument_option));
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},
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"read" => {
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options.push(OpenOption::Read(argument_option));
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},
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"write" => {
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options.push(OpenOption::Write(argument_option));
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},
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_ => {}
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}
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get_open_options(cx, &arguments[0], options);
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}
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}
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}
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fn check_for_duplicates(cx: &LateContext, options: &[OpenOption], span: Span) {
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// This code is almost duplicated (oh, the irony), but I haven't found a way to unify it.
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if options.iter().filter(|o| if let OpenOption::Create(_) = **o {true} else {false}).count() > 1 {
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span_lint(cx, NONSENSICAL_OPEN_OPTIONS, span, "The method \"create\" \
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is called more than once");
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}
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if options.iter().filter(|o| if let OpenOption::Append(_) = **o {true} else {false}).count() > 1 {
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span_lint(cx, NONSENSICAL_OPEN_OPTIONS, span, "The method \"append\" \
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is called more than once");
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}
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if options.iter().filter(|o| if let OpenOption::Truncate(_) = **o {true} else {false}).count() > 1 {
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span_lint(cx, NONSENSICAL_OPEN_OPTIONS, span, "The method \"truncate\" \
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is called more than once");
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}
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if options.iter().filter(|o| if let OpenOption::Read(_) = **o {true} else {false}).count() > 1 {
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span_lint(cx, NONSENSICAL_OPEN_OPTIONS, span, "The method \"read\" \
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is called more than once");
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}
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if options.iter().filter(|o| if let OpenOption::Write(_) = **o {true} else {false}).count() > 1 {
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span_lint(cx, NONSENSICAL_OPEN_OPTIONS, span, "The method \"write\" \
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is called more than once");
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}
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}
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fn check_for_inconsistencies(cx: &LateContext, options: &[OpenOption], span: Span) {
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// Truncate + read makes no sense.
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if options.iter().filter(|o| if let OpenOption::Read(Argument::True) = **o {true} else {false}).count() > 0 &&
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options.iter().filter(|o| if let OpenOption::Truncate(Argument::True) = **o {true} else {false}).count() > 0 {
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span_lint(cx, NONSENSICAL_OPEN_OPTIONS, span, "File opened with \"truncate\" and \"read\"");
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}
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// Append + truncate makes no sense.
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if options.iter().filter(|o| if let OpenOption::Append(Argument::True) = **o {true} else {false}).count() > 0 &&
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options.iter().filter(|o| if let OpenOption::Truncate(Argument::True) = **o {true} else {false}).count() > 0 {
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span_lint(cx, NONSENSICAL_OPEN_OPTIONS, span, "File opened with \"append\" and \"truncate\"");
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}
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}
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fn check_open_options(cx: &LateContext, options: &[OpenOption], span: Span) {
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check_for_duplicates(cx, options, span);
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check_for_inconsistencies(cx, options, span);
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}

‎src/utils.rs

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Original file line numberDiff line numberDiff line change
@@ -9,11 +9,12 @@ use std::borrow::Cow;
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use syntax::ast::Lit_::*;
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// module DefPaths for certain structs/enums we check for
12-
pub const OPTION_PATH: [&'static str; 3] = ["core", "option", "Option"];
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pub const RESULT_PATH: [&'static str; 3] = ["core", "result", "Result"];
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pub const STRING_PATH: [&'static str; 3] = ["collections", "string", "String"];
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pub const VEC_PATH: [&'static str; 3] = ["collections", "vec", "Vec"];
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pub const LL_PATH: [&'static str; 3] = ["collections", "linked_list", "LinkedList"];
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pub const OPTION_PATH: [&'static str; 3] = ["core", "option", "Option"];
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pub const RESULT_PATH: [&'static str; 3] = ["core", "result", "Result"];
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pub const STRING_PATH: [&'static str; 3] = ["collections", "string", "String"];
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pub const VEC_PATH: [&'static str; 3] = ["collections", "vec", "Vec"];
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pub const LL_PATH: [&'static str; 3] = ["collections", "linked_list", "LinkedList"];
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pub const OPEN_OPTIONS_PATH: [&'static str; 3] = ["std", "fs", "OpenOptions"];
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/// returns true this expn_info was expanded by any macro
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pub fn in_macro(cx: &LateContext, span: Span) -> bool {

‎tests/compile-fail/open_options.rs

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@@ -0,0 +1,16 @@
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#![feature(plugin)]
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#![plugin(clippy)]
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use std::fs::OpenOptions;
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#[allow(unused_must_use)]
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#[deny(nonsensical_open_options)]
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fn main() {
8+
OpenOptions::new().read(true).truncate(true).open("foo.txt"); //~ERROR File opened with "truncate" and "read"
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OpenOptions::new().append(true).truncate(true).open("foo.txt"); //~ERROR File opened with "append" and "truncate"
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OpenOptions::new().read(true).read(false).open("foo.txt"); //~ERROR The method "read" is called more than once
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OpenOptions::new().create(true).create(false).open("foo.txt"); //~ERROR The method "create" is called more than once
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OpenOptions::new().write(true).write(false).open("foo.txt"); //~ERROR The method "write" is called more than once
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OpenOptions::new().append(true).append(false).open("foo.txt"); //~ERROR The method "append" is called more than once
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OpenOptions::new().truncate(true).truncate(false).open("foo.txt"); //~ERROR The method "truncate" is called more than once
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}

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