76 lines
2.1 KiB
Rust
76 lines
2.1 KiB
Rust
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use rustc::lint::*;
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use rustc_front::hir;
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use rustc_front::intravisit;
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use syntax::ast;
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use syntax::codemap::Span;
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use utils::span_lint;
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/// **What it does:** Check for functions with too many parameters.
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///
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/// **Why is this bad?** Functions with lots of parameters are considered bad style and reduce
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/// readability (“what does the 5th parameter means?”). Consider grouping some parameters into a
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/// new type.
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///
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/// **Known problems:** None.
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///
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/// **Example:**
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///
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/// ```
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/// fn foo(x: u32, y: u32, name: &str, c: Color, w: f32, h: f32, a: f32, b: f32) { .. }
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/// ```
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declare_lint! {
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pub TOO_MANY_ARGUMENTS,
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Warn,
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"functions with too many arguments"
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}
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#[derive(Copy,Clone)]
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pub struct Functions {
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threshold: u64,
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}
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impl Functions {
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pub fn new(threshold: u64) -> Functions {
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Functions {
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threshold: threshold
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}
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}
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}
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impl LintPass for Functions {
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fn get_lints(&self) -> LintArray {
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lint_array!(TOO_MANY_ARGUMENTS)
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}
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}
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impl LateLintPass for Functions {
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fn check_fn(&mut self, cx: &LateContext, _: intravisit::FnKind, decl: &hir::FnDecl, _: &hir::Block, span: Span, nodeid: ast::NodeId) {
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use rustc::front::map::Node::*;
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if let Some(NodeItem(ref item)) = cx.tcx.map.find(cx.tcx.map.get_parent_node(nodeid)) {
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match item.node {
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hir::ItemImpl(_, _, _, Some(_), _, _) | hir::ItemDefaultImpl(..) => return,
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_ => (),
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}
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}
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self.check_arg_number(cx, decl, span);
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}
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fn check_trait_item(&mut self, cx: &LateContext, item: &hir::TraitItem) {
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if let hir::MethodTraitItem(ref sig, _) = item.node {
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self.check_arg_number(cx, &sig.decl, item.span);
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}
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}
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}
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impl Functions {
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fn check_arg_number(&self, cx: &LateContext, decl: &hir::FnDecl, span: Span) {
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let args = decl.inputs.len() as u64;
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if args > self.threshold {
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span_lint(cx, TOO_MANY_ARGUMENTS, span,
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&format!("this function has to many arguments ({}/{})", args, self.threshold));
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}
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}
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}
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