diff options
| -rw-r--r-- | clippy_utils/src/ty/type_certainty/mod.rs | 53 |
1 files changed, 40 insertions, 13 deletions
diff --git a/clippy_utils/src/ty/type_certainty/mod.rs b/clippy_utils/src/ty/type_certainty/mod.rs index 84df36c75bf..20bb0d44c59 100644 --- a/clippy_utils/src/ty/type_certainty/mod.rs +++ b/clippy_utils/src/ty/type_certainty/mod.rs @@ -12,6 +12,7 @@ //! be considered a bug. use crate::paths::{PathNS, lookup_path}; +use rustc_ast::{LitFloatType, LitIntType, LitKind}; use rustc_hir::def::{DefKind, Res}; use rustc_hir::def_id::DefId; use rustc_hir::intravisit::{InferKind, Visitor, VisitorExt, walk_qpath, walk_ty}; @@ -24,22 +25,24 @@ mod certainty; use certainty::{Certainty, Meet, join, meet}; pub fn expr_type_is_certain(cx: &LateContext<'_>, expr: &Expr<'_>) -> bool { - expr_type_certainty(cx, expr).is_certain() + expr_type_certainty(cx, expr, false).is_certain() } -fn expr_type_certainty(cx: &LateContext<'_>, expr: &Expr<'_>) -> Certainty { +/// Determine the type certainty of `expr`. `in_arg` indicates that the expression happens within +/// the evaluation of a function or method call argument. +fn expr_type_certainty(cx: &LateContext<'_>, expr: &Expr<'_>, in_arg: bool) -> Certainty { let certainty = match &expr.kind { ExprKind::Unary(_, expr) | ExprKind::Field(expr, _) | ExprKind::Index(expr, _, _) - | ExprKind::AddrOf(_, _, expr) => expr_type_certainty(cx, expr), + | ExprKind::AddrOf(_, _, expr) => expr_type_certainty(cx, expr, in_arg), - ExprKind::Array(exprs) => join(exprs.iter().map(|expr| expr_type_certainty(cx, expr))), + ExprKind::Array(exprs) => join(exprs.iter().map(|expr| expr_type_certainty(cx, expr, in_arg))), ExprKind::Call(callee, args) => { - let lhs = expr_type_certainty(cx, callee); + let lhs = expr_type_certainty(cx, callee, false); let rhs = if type_is_inferable_from_arguments(cx, expr) { - meet(args.iter().map(|arg| expr_type_certainty(cx, arg))) + meet(args.iter().map(|arg| expr_type_certainty(cx, arg, true))) } else { Certainty::Uncertain }; @@ -47,7 +50,7 @@ fn expr_type_certainty(cx: &LateContext<'_>, expr: &Expr<'_>) -> Certainty { }, ExprKind::MethodCall(method, receiver, args, _) => { - let mut receiver_type_certainty = expr_type_certainty(cx, receiver); + let mut receiver_type_certainty = expr_type_certainty(cx, receiver, false); // Even if `receiver_type_certainty` is `Certain(Some(..))`, the `Self` type in the method // identified by `type_dependent_def_id(..)` can differ. This can happen as a result of a `deref`, // for example. So update the `DefId` in `receiver_type_certainty` (if any). @@ -59,7 +62,8 @@ fn expr_type_certainty(cx: &LateContext<'_>, expr: &Expr<'_>) -> Certainty { let lhs = path_segment_certainty(cx, receiver_type_certainty, method, false); let rhs = if type_is_inferable_from_arguments(cx, expr) { meet( - std::iter::once(receiver_type_certainty).chain(args.iter().map(|arg| expr_type_certainty(cx, arg))), + std::iter::once(receiver_type_certainty) + .chain(args.iter().map(|arg| expr_type_certainty(cx, arg, true))), ) } else { Certainty::Uncertain @@ -67,16 +71,39 @@ fn expr_type_certainty(cx: &LateContext<'_>, expr: &Expr<'_>) -> Certainty { lhs.join(rhs) }, - ExprKind::Tup(exprs) => meet(exprs.iter().map(|expr| expr_type_certainty(cx, expr))), + ExprKind::Tup(exprs) => meet(exprs.iter().map(|expr| expr_type_certainty(cx, expr, in_arg))), - ExprKind::Binary(_, lhs, rhs) => expr_type_certainty(cx, lhs).meet(expr_type_certainty(cx, rhs)), + ExprKind::Binary(_, lhs, rhs) => { + // If one of the side of the expression is uncertain, the certainty will come from the other side, + // with no information on the type. + match ( + expr_type_certainty(cx, lhs, in_arg), + expr_type_certainty(cx, rhs, in_arg), + ) { + (Certainty::Uncertain, Certainty::Certain(_)) | (Certainty::Certain(_), Certainty::Uncertain) => { + Certainty::Certain(None) + }, + (l, r) => l.meet(r), + } + }, - ExprKind::Lit(_) => Certainty::Certain(None), + ExprKind::Lit(lit) => { + if !in_arg + && matches!( + lit.node, + LitKind::Int(_, LitIntType::Unsuffixed) | LitKind::Float(_, LitFloatType::Unsuffixed) + ) + { + Certainty::Uncertain + } else { + Certainty::Certain(None) + } + }, ExprKind::Cast(_, ty) => type_certainty(cx, ty), ExprKind::If(_, if_expr, Some(else_expr)) => { - expr_type_certainty(cx, if_expr).join(expr_type_certainty(cx, else_expr)) + expr_type_certainty(cx, if_expr, in_arg).join(expr_type_certainty(cx, else_expr, in_arg)) }, ExprKind::Path(qpath) => qpath_certainty(cx, qpath, false), @@ -248,7 +275,7 @@ fn path_segment_certainty( let lhs = local.ty.map_or(Certainty::Uncertain, |ty| type_certainty(cx, ty)); let rhs = local .init - .map_or(Certainty::Uncertain, |init| expr_type_certainty(cx, init)); + .map_or(Certainty::Uncertain, |init| expr_type_certainty(cx, init, false)); let certainty = lhs.join(rhs); if resolves_to_type { certainty |