a67e55f3f0
Since lint messages often are suffixed by ", #[warn(xxx)] on by default" this trailing period produces an ugly clash with the comma.
61 lines
2.3 KiB
Rust
61 lines
2.3 KiB
Rust
use syntax::ast::*;
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use rustc::lint::{Context, LintPass, LintArray, Lint, Level};
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use syntax::codemap::{Span, Spanned};
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use syntax::print::pprust::expr_to_string;
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use utils::span_lint;
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#[allow(missing_copy_implementations)]
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pub struct EtaPass;
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declare_lint!(pub REDUNDANT_CLOSURE, Warn,
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"Warn on usage of redundant closures, i.e. `|a| foo(a)`");
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impl LintPass for EtaPass {
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fn get_lints(&self) -> LintArray {
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lint_array!(REDUNDANT_CLOSURE)
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}
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fn check_expr(&mut self, cx: &Context, expr: &Expr) {
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if let ExprClosure(_, ref decl, ref blk) = expr.node {
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if !blk.stmts.is_empty() {
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// || {foo(); bar()}; can't be reduced here
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return;
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}
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if let Some(ref ex) = blk.expr {
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if let ExprCall(ref caller, ref args) = ex.node {
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if args.len() != decl.inputs.len() {
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// Not the same number of arguments, there
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// is no way the closure is the same as the function
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return;
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}
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for (ref a1, ref a2) in decl.inputs.iter().zip(args) {
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if let PatIdent(_, ident, _) = a1.pat.node {
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// XXXManishearth Should I be checking the binding mode here?
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if let ExprPath(None, ref p) = a2.node {
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if p.segments.len() != 1 {
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// If it's a proper path, it can't be a local variable
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return;
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}
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if p.segments[0].identifier != ident.node {
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// The two idents should be the same
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return
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}
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} else {
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return
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}
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} else {
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return
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}
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}
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span_lint(cx, REDUNDANT_CLOSURE, expr.span,
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&format!("redundant closure found. Consider using `{}` in its place",
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expr_to_string(caller))[..])
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}
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}
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}
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}
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}
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