src/tools/clippy/clippy_lints/src/functions/too_many_arguments.rs

   1 use rustc_hir::{self as hir, intravisit};
   2 use rustc_lint::LateContext;
   3 use rustc_span::Span;
   4 use rustc_target::spec::abi::Abi;
   5
   6 use clippy_utils::diagnostics::span_lint;
   7 use clippy_utils::is_trait_impl_item;
   8
   9 use super::TOO_MANY_ARGUMENTS;
  10
  11 pub(super) fn check_fn(
  12     cx: &LateContext<'tcx>,
  13     kind: intravisit::FnKind<'tcx>,
  14     decl: &'tcx hir::FnDecl<'_>,
  15     span: Span,
  16     hir_id: hir::HirId,
  17     too_many_arguments_threshold: u64,
  18 ) {
  19     // don't warn for implementations, it's not their fault
  20     if !is_trait_impl_item(cx, hir_id) {
  21         // don't lint extern functions decls, it's not their fault either
  22         match kind {
  23             intravisit::FnKind::Method(
  24                 _,
  25                 &hir::FnSig {
  26                     header: hir::FnHeader { abi: Abi::Rust, .. },
  27                     ..
  28                 },
  29                 _,
  30             )
  31             | intravisit::FnKind::ItemFn(_, _, hir::FnHeader { abi: Abi::Rust, .. }, _) => check_arg_number(
  32                 cx,
  33                 decl,
  34                 span.with_hi(decl.output.span().hi()),
  35                 too_many_arguments_threshold,
  36             ),
  37             _ => {},
  38         }
  39     }
  40 }
  41
  42 pub(super) fn check_trait_item(
  43     cx: &LateContext<'tcx>,
  44     item: &'tcx hir::TraitItem<'_>,
  45     too_many_arguments_threshold: u64,
  46 ) {
  47     if let hir::TraitItemKind::Fn(ref sig, _) = item.kind {
  48         // don't lint extern functions decls, it's not their fault
  49         if sig.header.abi == Abi::Rust {
  50             check_arg_number(
  51                 cx,
  52                 sig.decl,
  53                 item.span.with_hi(sig.decl.output.span().hi()),
  54                 too_many_arguments_threshold,
  55             );
  56         }
  57     }
  58 }
  59
  60 fn check_arg_number(cx: &LateContext<'_>, decl: &hir::FnDecl<'_>, fn_span: Span, too_many_arguments_threshold: u64) {
  61     let args = decl.inputs.len() as u64;
  62     if args > too_many_arguments_threshold {
  63         span_lint(
  64             cx,
  65             TOO_MANY_ARGUMENTS,
  66             fn_span,
  67             &format!(
  68                 "this function has too many arguments ({}/{})",
  69                 args, too_many_arguments_threshold
  70             ),
  71         );
  72     }
  73 }