rustup https://github.com/rust-lang/rust/pull/67455

[rust.git] / clippy_lints / src / enum_clike.rs

diff --git a/clippy_lints/src/enum_clike.rs b/clippy_lints/src/enum_clike.rs
index c65cf92590a6fb32604907981d577ade122bf005..c4b368a6e2e8054ba32292d6ec373696142f2c8e 100644 (file)
--- a/clippy_lints/src/enum_clike.rs
+++ b/clippy_lints/src/enum_clike.rs
@@ -1,78 +1,86 @@
 //! lint on C-like enums that are `repr(isize/usize)` and have values that
 //! don't fit into an `i32`
 
-use rustc::lint::*;
-use rustc::middle::const_val::ConstVal;
-use rustc_const_math::*;
+use crate::consts::{miri_to_const, Constant};
+use crate::utils::span_lint;
+use rustc::declare_lint_pass;
 use rustc::hir::*;
+use rustc::lint::{LateContext, LateLintPass, LintArray, LintPass};
+use rustc::mir::interpret::GlobalId;
 use rustc::ty;
-use rustc::traits::Reveal;
-use rustc::ty::subst::Substs;
-use utils::span_lint;
+use rustc::ty::subst::InternalSubsts;
+use rustc::ty::util::IntTypeExt;
+use rustc_session::declare_tool_lint;
+use std::convert::TryFrom;
+use syntax::ast::{IntTy, UintTy};
 
-/// **What it does:** Checks for C-like enumerations that are
-/// `repr(isize/usize)` and have values that don't fit into an `i32`.
-///
-/// **Why is this bad?** This will truncate the variant value on 32 bit
-/// architectures, but works fine on 64 bit.
-///
-/// **Known problems:** None.
-///
-/// **Example:**
-/// ```rust
-/// #[repr(usize)]
-/// enum NonPortable {
-///     X = 0x1_0000_0000,
-///     Y = 0
-/// }
-/// ```
-declare_lint! {
+declare_clippy_lint! {
+    /// **What it does:** Checks for C-like enumerations that are
+    /// `repr(isize/usize)` and have values that don't fit into an `i32`.
+    ///
+    /// **Why is this bad?** This will truncate the variant value on 32 bit
+    /// architectures, but works fine on 64 bit.
+    ///
+    /// **Known problems:** None.
+    ///
+    /// **Example:**
+    /// ```rust
+    /// # #[cfg(target_pointer_width = "64")]
+    /// #[repr(usize)]
+    /// enum NonPortable {
+    ///     X = 0x1_0000_0000,
+    ///     Y = 0,
+    /// }
+    /// ```
     pub ENUM_CLIKE_UNPORTABLE_VARIANT,
-    Warn,
+    correctness,
     "C-like enums that are `repr(isize/usize)` and have values that don't fit into an `i32`"
 }
 
-pub struct UnportableVariant;
-
-impl LintPass for UnportableVariant {
-    fn get_lints(&self) -> LintArray {
-        lint_array!(ENUM_CLIKE_UNPORTABLE_VARIANT)
-    }
-}
+declare_lint_pass!(UnportableVariant => [ENUM_CLIKE_UNPORTABLE_VARIANT]);
 
 impl<'a, 'tcx> LateLintPass<'a, 'tcx> for UnportableVariant {
-    #[allow(cast_possible_truncation, cast_sign_loss)]
+    #[allow(clippy::cast_possible_truncation, clippy::cast_possible_wrap, clippy::cast_sign_loss)]
     fn check_item(&mut self, cx: &LateContext<'a, 'tcx>, item: &'tcx Item) {
-        if let ItemEnum(ref def, _) = item.node {
+        if cx.tcx.data_layout.pointer_size.bits() != 64 {
+            return;
+        }
+        if let ItemKind::Enum(def, _) = &item.kind {
             for var in &def.variants {
-                let variant = &var.node;
-                if let Some(body_id) = variant.disr_expr {
-                    let expr = &cx.tcx.hir.body(body_id).value;
-                    let did = cx.tcx.hir.body_owner_def_id(body_id);
-                    let param_env = ty::ParamEnv::empty(Reveal::UserFacing);
-                    let substs = Substs::identity_for_item(cx.tcx.global_tcx(), did);
-                    let bad = match cx.tcx
-                        .at(expr.span)
-                        .const_eval(param_env.and((did, substs)))
-                    {
-                        Ok(&ty::Const {
-                            val: ConstVal::Integral(Usize(Us64(i))),
-                            ..
-                        }) => u64::from(i as u32) != i,
-                        Ok(&ty::Const {
-                            val: ConstVal::Integral(Isize(Is64(i))),
-                            ..
-                        }) => i64::from(i as i32) != i,
-                        _ => false,
+                if let Some(anon_const) = &var.disr_expr {
+                    let param_env = ty::ParamEnv::empty();
+                    let def_id = cx.tcx.hir().body_owner_def_id(anon_const.body);
+                    let substs = InternalSubsts::identity_for_item(cx.tcx, def_id);
+                    let instance = ty::Instance::new(def_id, substs);
+                    let c_id = GlobalId {
+                        instance,
+                        promoted: None,
                     };
-                    if bad {
+                    let constant = cx.tcx.const_eval(param_env.and(c_id)).ok();
+                    if let Some(Constant::Int(val)) = constant.and_then(miri_to_const) {
+                        let mut ty = cx.tcx.type_of(def_id);
+                        if let ty::Adt(adt, _) = ty.kind {
+                            if adt.is_enum() {
+                                ty = adt.repr.discr_type().to_ty(cx.tcx);
+                            }
+                        }
+                        match ty.kind {
+                            ty::Int(IntTy::Isize) => {
+                                let val = ((val as i128) << 64) >> 64;
+                                if i32::try_from(val).is_ok() {
+                                    continue;
+                                }
+                            },
+                            ty::Uint(UintTy::Usize) if val > u128::from(u32::max_value()) => {},
+                            _ => continue,
+                        }
                         span_lint(
                             cx,
                             ENUM_CLIKE_UNPORTABLE_VARIANT,
                             var.span,
                             "Clike enum variant discriminant is not portable to 32-bit targets",
                         );
-                    }
+                    };
                 }
             }
         }