38 lines
1.1 KiB
Rust
38 lines
1.1 KiB
Rust
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use rustc::lint::*;
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use rustc_front::hir::*;
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use utils;
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declare_lint! {
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pub USELESS_TRANSMUTE,
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Warn,
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"transmutes that have the same to and from types"
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}
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pub struct UselessTransmute;
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impl LintPass for UselessTransmute {
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fn get_lints(&self) -> LintArray {
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lint_array!(USELESS_TRANSMUTE)
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}
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}
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impl LateLintPass for UselessTransmute {
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fn check_expr(&mut self, cx: &LateContext, e: &Expr) {
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if let ExprCall(ref path_expr, ref args) = e.node {
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if let ExprPath(None, _) = path_expr.node {
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let def_id = cx.tcx.def_map.borrow()[&path_expr.id].def_id();
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if utils::match_def_path(cx, def_id, &["core", "intrinsics", "transmute"]) {
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let from_ty = cx.tcx.expr_ty(&args[0]);
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let to_ty = cx.tcx.expr_ty(e);
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if from_ty == to_ty {
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cx.span_lint(USELESS_TRANSMUTE, e.span,
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&format!("transmute from a type (`{}`) to itself", from_ty));
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}
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}
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}
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}
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}
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}
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