[default_numeric_fallback] do not lint on constants

clippy_lints/src/default_numeric_fallback.rs

@@ -1,12 +1,12 @@
 use clippy_utils::diagnostics::span_lint_hir_and_then;
-use clippy_utils::numeric_literal;
 use clippy_utils::source::snippet_opt;
+use clippy_utils::{get_parent_node, numeric_literal};
 use if_chain::if_chain;
 use rustc_ast::ast::{LitFloatType, LitIntType, LitKind};
 use rustc_errors::Applicability;
 use rustc_hir::{
  intravisit::{walk_expr, walk_stmt, Visitor},
- Body, Expr, ExprKind, HirId, Lit, Stmt, StmtKind,
+ Body, Expr, ExprKind, HirId, ItemKind, Lit, Node, Stmt, StmtKind,
 };
 use rustc_lint::{LateContext, LateLintPass, LintContext};
 use rustc_middle::{
@@ -55,22 +55,31 @@ declare_lint_pass!(DefaultNumericFallback => [DEFAULT_NUMERIC_FALLBACK]);
 
 impl<'tcx> LateLintPass<'tcx> for DefaultNumericFallback {
  fn check_body(&mut self, cx: &LateContext<'tcx>, body: &'tcx Body<'_>) {
- let mut visitor = NumericFallbackVisitor::new(cx);
+ let is_parent_const = if let Some(Node::Item(item)) = get_parent_node(cx.tcx, body.id().hir_id) {
+ matches!(item.kind, ItemKind::Const(..))
+ } else {
+ false
+ };
+ let mut visitor = NumericFallbackVisitor::new(cx, is_parent_const);
  visitor.visit_body(body);
  }
 }
 
 struct NumericFallbackVisitor<'a, 'tcx> {
  /// Stack manages type bound of exprs. The top element holds current expr type.
- ty_bounds: Vec<TyBound<'tcx>>,
+ ty_bounds: Vec<ExplicitTyBound>,
 
  cx: &'a LateContext<'tcx>,
 }
 
 impl<'a, 'tcx> NumericFallbackVisitor<'a, 'tcx> {
- fn new(cx: &'a LateContext<'tcx>) -> Self {
+ fn new(cx: &'a LateContext<'tcx>, is_parent_const: bool) -> Self {
  Self {
- ty_bounds: vec![TyBound::Nothing],
+ ty_bounds: vec![if is_parent_const {
+ ExplicitTyBound(true)
+ } else {
+ ExplicitTyBound(false)
+ }],
  cx,
  }
  }
@@ -79,10 +88,9 @@ impl<'a, 'tcx> NumericFallbackVisitor<'a, 'tcx> {
  fn check_lit(&self, lit: &Lit, lit_ty: Ty<'tcx>, emit_hir_id: HirId) {
  if_chain! {
  if !in_external_macro(self.cx.sess(), lit.span);
- if let Some(ty_bound) = self.ty_bounds.last();
+ if matches!(self.ty_bounds.last(), Some(ExplicitTyBound(false)));
  if matches!(lit.node,
  LitKind::Int(_, LitIntType::Unsuffixed) | LitKind::Float(_, LitFloatType::Unsuffixed));
- if !ty_bound.is_numeric();
  then {
  let (suffix, is_float) = match lit_ty.kind() {
  ty::Int(IntTy::I32) => ("i32", false),
@@ -123,7 +131,7 @@ impl<'a, 'tcx> Visitor<'tcx> for NumericFallbackVisitor<'a, 'tcx> {
  if let Some(fn_sig) = fn_sig_opt(self.cx, func.hir_id) {
  for (expr, bound) in iter::zip(*args, fn_sig.skip_binder().inputs()) {
  // Push found arg type, then visit arg.
- self.ty_bounds.push(TyBound::Ty(*bound));
+ self.ty_bounds.push((*bound).into());
  self.visit_expr(expr);
  self.ty_bounds.pop();
  }
@@ -135,7 +143,7 @@ impl<'a, 'tcx> Visitor<'tcx> for NumericFallbackVisitor<'a, 'tcx> {
  if let Some(def_id) = self.cx.typeck_results().type_dependent_def_id(expr.hir_id) {
  let fn_sig = self.cx.tcx.fn_sig(def_id).skip_binder();
  for (expr, bound) in iter::zip(std::iter::once(*receiver).chain(args.iter()), fn_sig.inputs()) {
- self.ty_bounds.push(TyBound::Ty(*bound));
+ self.ty_bounds.push((*bound).into());
  self.visit_expr(expr);
  self.ty_bounds.pop();
  }
@@ -169,7 +177,7 @@ impl<'a, 'tcx> Visitor<'tcx> for NumericFallbackVisitor<'a, 'tcx> {
 
  // Visit base with no bound.
  if let Some(base) = base {
- self.ty_bounds.push(TyBound::Nothing);
+ self.ty_bounds.push(ExplicitTyBound(false));
  self.visit_expr(base);
  self.ty_bounds.pop();
  }
@@ -192,15 +200,10 @@ impl<'a, 'tcx> Visitor<'tcx> for NumericFallbackVisitor<'a, 'tcx> {
 
  fn visit_stmt(&mut self, stmt: &'tcx Stmt<'_>) {
  match stmt.kind {
- StmtKind::Local(local) => {
- if local.ty.is_some() {
- self.ty_bounds.push(TyBound::Any);
- } else {
- self.ty_bounds.push(TyBound::Nothing);
- }
- },
+ // we cannot check the exact type since it's a hir::Ty which does not implement `is_numeric`
+ StmtKind::Local(local) => self.ty_bounds.push(ExplicitTyBound(local.ty.is_some())),
 
- _ => self.ty_bounds.push(TyBound::Nothing),
+ _ => self.ty_bounds.push(ExplicitTyBound(false)),
  }
 
  walk_stmt(self, stmt);
@@ -218,28 +221,18 @@ fn fn_sig_opt<'tcx>(cx: &LateContext<'tcx>, hir_id: HirId) -> Option<PolyFnSig<'
  }
 }
 
+/// Wrapper around a `bool` to make the meaning of the value clearer
 #[derive(Debug, Clone, Copy)]
-enum TyBound<'tcx> {
- Any,
- Ty(Ty<'tcx>),
- Nothing,
-}
+struct ExplicitTyBound(pub bool);
 
-impl<'tcx> TyBound<'tcx> {
- fn is_numeric(self) -> bool {
- match self {
- TyBound::Any => true,
- TyBound::Ty(t) => t.is_numeric(),
- TyBound::Nothing => false,
- }
+impl<'tcx> From<Ty<'tcx>> for ExplicitTyBound {
+ fn from(v: Ty<'tcx>) -> Self {
+ Self(v.is_numeric())
  }
 }
 
-impl<'tcx> From<Option<Ty<'tcx>>> for TyBound<'tcx> {
+impl<'tcx> From<Option<Ty<'tcx>>> for ExplicitTyBound {
  fn from(v: Option<Ty<'tcx>>) -> Self {
- match v {
- Some(t) => TyBound::Ty(t),
- None => TyBound::Nothing,
- }
+ Self(v.map_or(false, Ty::is_numeric))
  }
 }

tests/ui/default_numeric_fallback_f64.fixed

@@ -33,6 +33,7 @@ mod basic_expr {
  let x: [f64; 3] = [1., 2., 3.];
  let x: (f64, f64) = if true { (1., 2.) } else { (3., 4.) };
  let x: _ = 1.;
+ const X: f32 = 1.;
  }
 }
 
@@ -59,6 +60,14 @@ mod nested_local {
  // Should NOT lint this because this literal is bound to `_` of outer `Local`.
  2.
  };
+
+ const X: f32 = {
+ // Should lint this because this literal is not bound to any types.
+ let y = 1.0_f64;
+
+ // Should NOT lint this because this literal is bound to `_` of outer `Local`.
+ 1.
+ };
  }
 }
 

tests/ui/default_numeric_fallback_f64.rs

@@ -33,6 +33,7 @@ mod basic_expr {
  let x: [f64; 3] = [1., 2., 3.];
  let x: (f64, f64) = if true { (1., 2.) } else { (3., 4.) };
  let x: _ = 1.;
+ const X: f32 = 1.;
  }
 }
 
@@ -59,6 +60,14 @@ mod nested_local {
  // Should NOT lint this because this literal is bound to `_` of outer `Local`.
  2.
  };
+
+ const X: f32 = {
+ // Should lint this because this literal is not bound to any types.
+ let y = 1.;
+
+ // Should NOT lint this because this literal is bound to `_` of outer `Local`.
+ 1.
+ };
  }
 }
 

tests/ui/default_numeric_fallback_f64.stderr

@@ -61,79 +61,85 @@ LL | _ => 1.,
  | ^^ help: consider adding suffix: `1.0_f64`
 
 error: default numeric fallback might occur
- --> $DIR/default_numeric_fallback_f64.rs:43:21
+ --> $DIR/default_numeric_fallback_f64.rs:44:21
  |
 LL | let y = 1.;
  | ^^ help: consider adding suffix: `1.0_f64`
 
 error: default numeric fallback might occur
- --> $DIR/default_numeric_fallback_f64.rs:51:21
+ --> $DIR/default_numeric_fallback_f64.rs:52:21
  |
 LL | let y = 1.;
  | ^^ help: consider adding suffix: `1.0_f64`
 
 error: default numeric fallback might occur
- --> $DIR/default_numeric_fallback_f64.rs:57:21
+ --> $DIR/default_numeric_fallback_f64.rs:58:21
  |
 LL | let y = 1.;
  | ^^ help: consider adding suffix: `1.0_f64`
 
 error: default numeric fallback might occur
- --> $DIR/default_numeric_fallback_f64.rs:69:9
+ --> $DIR/default_numeric_fallback_f64.rs:66:21
+ |
+LL | let y = 1.;
+ | ^^ help: consider adding suffix: `1.0_f64`
+
+error: default numeric fallback might occur
+ --> $DIR/default_numeric_fallback_f64.rs:78:9
  |
 LL | 1.
  | ^^ help: consider adding suffix: `1.0_f64`
 
 error: default numeric fallback might occur
- --> $DIR/default_numeric_fallback_f64.rs:75:27
+ --> $DIR/default_numeric_fallback_f64.rs:84:27
  |
 LL | let f = || -> _ { 1. };
  | ^^ help: consider adding suffix: `1.0_f64`
 
 error: default numeric fallback might occur
- --> $DIR/default_numeric_fallback_f64.rs:79:29
+ --> $DIR/default_numeric_fallback_f64.rs:88:29
  |
 LL | let f = || -> f64 { 1. };
  | ^^ help: consider adding suffix: `1.0_f64`
 
 error: default numeric fallback might occur
- --> $DIR/default_numeric_fallback_f64.rs:93:21
+ --> $DIR/default_numeric_fallback_f64.rs:102:21
  |
 LL | generic_arg(1.);
  | ^^ help: consider adding suffix: `1.0_f64`
 
 error: default numeric fallback might occur
- --> $DIR/default_numeric_fallback_f64.rs:96:32
+ --> $DIR/default_numeric_fallback_f64.rs:105:32
  |
 LL | let x: _ = generic_arg(1.);
  | ^^ help: consider adding suffix: `1.0_f64`
 
 error: default numeric fallback might occur
- --> $DIR/default_numeric_fallback_f64.rs:114:28
+ --> $DIR/default_numeric_fallback_f64.rs:123:28
  |
 LL | GenericStruct { x: 1. };
  | ^^ help: consider adding suffix: `1.0_f64`
 
 error: default numeric fallback might occur
- --> $DIR/default_numeric_fallback_f64.rs:117:36
+ --> $DIR/default_numeric_fallback_f64.rs:126:36
  |
 LL | let _ = GenericStruct { x: 1. };
  | ^^ help: consider adding suffix: `1.0_f64`
 
 error: default numeric fallback might occur
- --> $DIR/default_numeric_fallback_f64.rs:135:24
+ --> $DIR/default_numeric_fallback_f64.rs:144:24
  |
 LL | GenericEnum::X(1.);
  | ^^ help: consider adding suffix: `1.0_f64`
 
 error: default numeric fallback might occur
- --> $DIR/default_numeric_fallback_f64.rs:155:23
+ --> $DIR/default_numeric_fallback_f64.rs:164:23
  |
 LL | s.generic_arg(1.);
  | ^^ help: consider adding suffix: `1.0_f64`
 
 error: default numeric fallback might occur
- --> $DIR/default_numeric_fallback_f64.rs:162:21
+ --> $DIR/default_numeric_fallback_f64.rs:171:21
  |
 LL | let x = 22.;
  | ^^^ help: consider adding suffix: `22.0_f64`
@@ -143,5 +149,5 @@ LL | internal_macro!();
  |
  = note: this error originates in the macro `internal_macro` (in Nightly builds, run with -Z macro-backtrace for more info)
 
-error: aborting due to 23 previous errors
+error: aborting due to 24 previous errors
 

tests/ui/default_numeric_fallback_i32.fixed

@@ -33,6 +33,8 @@ mod basic_expr {
  let x: [i32; 3] = [1, 2, 3];
  let x: (i32, i32) = if true { (1, 2) } else { (3, 4) };
  let x: _ = 1;
+ let x: u64 = 1;
+ const CONST_X: i8 = 1;
  }
 }
 
@@ -59,6 +61,14 @@ mod nested_local {
  // Should NOT lint this because this literal is bound to `_` of outer `Local`.
  2
  };
+
+ const CONST_X: i32 = {
+ // Should lint this because this literal is not bound to any types.
+ let y = 1_i32;
+
+ // Should NOT lint this because this literal is bound to `_` of outer `Local`.
+ 1
+ };
  }
 }
 

tests/ui/default_numeric_fallback_i32.rs

@@ -33,6 +33,8 @@ mod basic_expr {
  let x: [i32; 3] = [1, 2, 3];
  let x: (i32, i32) = if true { (1, 2) } else { (3, 4) };
  let x: _ = 1;
+ let x: u64 = 1;
+ const CONST_X: i8 = 1;
  }
 }
 
@@ -59,6 +61,14 @@ mod nested_local {
  // Should NOT lint this because this literal is bound to `_` of outer `Local`.
  2
  };
+
+ const CONST_X: i32 = {
+ // Should lint this because this literal is not bound to any types.
+ let y = 1;
+
+ // Should NOT lint this because this literal is bound to `_` of outer `Local`.
+ 1
+ };
  }
 }