Merge branch 'master' into fix-4514

clippy_lints/src/cognitive_complexity.rs

@@ -1,15 +1,13 @@
 //! calculate cognitive complexity and warn about overly complex functions
 
-use rustc::cfg::CFG;
 use rustc::hir::intravisit::{walk_expr, NestedVisitorMap, Visitor};
 use rustc::hir::*;
 use rustc::lint::{LateContext, LateLintPass, LintArray, LintContext, LintPass};
-use rustc::ty;
 use rustc::{declare_tool_lint, impl_lint_pass};
 use syntax::ast::Attribute;
 use syntax::source_map::Span;
 
-use crate::utils::{is_allowed, match_type, paths, span_help_and_lint, LimitStack};
+use crate::utils::{match_type, paths, span_help_and_lint, LimitStack};
 
 declare_clippy_lint! {
  /// **What it does:** Checks for methods with high cognitive complexity.
@@ -46,30 +44,11 @@ impl CognitiveComplexity {
  return;
  }
 
- let cfg = CFG::new(cx.tcx, body);
  let expr = &body.value;
- let n = cfg.graph.len_nodes() as u64;
- let e = cfg.graph.len_edges() as u64;
- if e + 2 < n {
- // the function has unreachable code, other lints should catch this
- return;
- }
- let cc = e + 2 - n;
- let mut helper = CCHelper {
- match_arms: 0,
- divergence: 0,
- short_circuits: 0,
- returns: 0,
- cx,
- };
+
+ let mut helper = CCHelper { cc: 1, returns: 0 };
  helper.visit_expr(expr);
- let CCHelper {
- match_arms,
- divergence,
- short_circuits,
- returns,
- ..
- } = helper;
+ let CCHelper { cc, returns } = helper;
  let ret_ty = cx.tables.node_type(expr.hir_id);
  let ret_adjust = if match_type(cx, ret_ty, &paths::RESULT) {
  returns
@@ -78,36 +57,23 @@ impl CognitiveComplexity {
  (returns / 2)
  };
 
- if cc + divergence < match_arms + short_circuits {
- report_cc_bug(
+ let mut rust_cc = cc;
+ // prevent degenerate cases where unreachable code contains `return` statements
+ if rust_cc >= ret_adjust {
+ rust_cc -= ret_adjust;
+ }
+ if rust_cc > self.limit.limit() {
+ span_help_and_lint(
  cx,
- cc,
- match_arms,
- divergence,
- short_circuits,
- ret_adjust,
+ COGNITIVE_COMPLEXITY,
  span,
- body.id().hir_id,
+ &format!(
+ "the function has a cognitive complexity of ({}/{})",
+ rust_cc,
+ self.limit.limit()
+ ),
+ "you could split it up into multiple smaller functions",
  );
- } else {
- let mut rust_cc = cc + divergence - match_arms - short_circuits;
- // prevent degenerate cases where unreachable code contains `return` statements
- if rust_cc >= ret_adjust {
- rust_cc -= ret_adjust;
- }
- if rust_cc > self.limit.limit() {
- span_help_and_lint(
- cx,
- COGNITIVE_COMPLEXITY,
- span,
- &format!(
- "the function has a cognitive complexity of ({}/{})",
- rust_cc,
- self.limit.limit()
- ),
- "you could split it up into multiple smaller functions",
- );
- }
  }
  }
 }
@@ -136,99 +102,27 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for CognitiveComplexity {
  }
 }
 
-struct CCHelper<'a, 'tcx> {
- match_arms: u64,
- divergence: u64,
+struct CCHelper {
+ cc: u64,
  returns: u64,
- short_circuits: u64, // && and ||
- cx: &'a LateContext<'a, 'tcx>,
 }
 
-impl<'a, 'tcx> Visitor<'tcx> for CCHelper<'a, 'tcx> {
+impl<'tcx> Visitor<'tcx> for CCHelper {
  fn visit_expr(&mut self, e: &'tcx Expr) {
+ walk_expr(self, e);
  match e.node {
  ExprKind::Match(_, ref arms, _) => {
- walk_expr(self, e);
  let arms_n: u64 = arms.iter().map(|arm| arm.pats.len() as u64).sum();
  if arms_n > 1 {
- self.match_arms += arms_n - 2;
- }
- },
- ExprKind::Call(ref callee, _) => {
- walk_expr(self, e);
- let ty = self.cx.tables.node_type(callee.hir_id);
- match ty.sty {
- ty::FnDef(..) | ty::FnPtr(_) => {
- let sig = ty.fn_sig(self.cx.tcx);
- if sig.skip_binder().output().sty == ty::Never {
- self.divergence += 1;
- }
- },
- _ => (),
- }
- },
- ExprKind::Closure(.., _) => (),
- ExprKind::Binary(op, _, _) => {
- walk_expr(self, e);
- match op.node {
- BinOpKind::And | BinOpKind::Or => self.short_circuits += 1,
- _ => (),
+ self.cc += 1;
  }
+ self.cc += arms.iter().filter(|arm| arm.guard.is_some()).count() as u64;
  },
  ExprKind::Ret(_) => self.returns += 1,
- _ => walk_expr(self, e),
+ _ => {},
  }
  }
  fn nested_visit_map<'this>(&'this mut self) -> NestedVisitorMap<'this, 'tcx> {
  NestedVisitorMap::None
  }
 }
-
-#[cfg(feature = "debugging")]
-#[allow(clippy::too_many_arguments)]
-fn report_cc_bug(
- _: &LateContext<'_, '_>,
- cc: u64,
- narms: u64,
- div: u64,
- shorts: u64,
- returns: u64,
- span: Span,
- _: HirId,
-) {
- span_bug!(
- span,
- "Clippy encountered a bug calculating cognitive complexity: cc = {}, arms = {}, \
- div = {}, shorts = {}, returns = {}. Please file a bug report.",
- cc,
- narms,
- div,
- shorts,
- returns
- );
-}
-#[cfg(not(feature = "debugging"))]
-#[allow(clippy::too_many_arguments)]
-fn report_cc_bug(
- cx: &LateContext<'_, '_>,
- cc: u64,
- narms: u64,
- div: u64,
- shorts: u64,
- returns: u64,
- span: Span,
- id: HirId,
-) {
- if !is_allowed(cx, COGNITIVE_COMPLEXITY, id) {
- cx.sess().span_note_without_error(
- span,
- &format!(
- "Clippy encountered a bug calculating cognitive complexity \
- (hide this message with `#[allow(cognitive_complexity)]`): \
- cc = {}, arms = {}, div = {}, shorts = {}, returns = {}. \
- Please file a bug report.",
- cc, narms, div, shorts, returns
- ),
- );
- }
-}

clippy_lints/src/non_expressive_names.rs

@@ -136,6 +136,9 @@ impl<'a, 'tcx, 'b> Visitor<'tcx> for SimilarNamesNameVisitor<'a, 'tcx, 'b> {
  }
  }
  },
+ // just go through the first pattern, as either all patterns
+ // bind the same bindings or rustc would have errored much earlier
+ PatKind::Or(ref pats) => self.visit_pat(&pats[0]),
  _ => walk_pat(self, pat),
  }
  }
@@ -325,8 +328,6 @@ impl<'a, 'tcx> Visitor<'tcx> for SimilarNamesLocalVisitor<'a, 'tcx> {
  self.single_char_names.push(vec![]);
 
  self.apply(|this| {
- // just go through the first pattern, as either all patterns
- // bind the same bindings or rustc would have errored much earlier
  SimilarNamesNameVisitor(this).visit_pat(&arm.pat);
  this.apply(|this| walk_expr(this, &arm.body));
  });