]> git.lizzy.rs Git - rust.git/blobdiff - clippy_utils/src/consts.rs
add eq constraints on associated constants
[rust.git] / clippy_utils / src / consts.rs
index 8af10ebe777ea0ed4c2c9b54df7b6017558a9355..e09a663538ddcfeff5899eae3d0af5155b6a2340 100644 (file)
@@ -1,6 +1,6 @@
 #![allow(clippy::float_cmp)]
 
-use crate::{clip, sext, unsext};
+use crate::{clip, is_direct_expn_of, sext, unsext};
 use if_chain::if_chain;
 use rustc_ast::ast::{self, LitFloatType, LitKind};
 use rustc_data_structures::sync::Lrc;
@@ -140,12 +140,10 @@ pub fn partial_cmp(tcx: TyCtxt<'_>, cmp_type: Ty<'_>, left: &Self, right: &Self)
             (&Self::F64(l), &Self::F64(r)) => l.partial_cmp(&r),
             (&Self::F32(l), &Self::F32(r)) => l.partial_cmp(&r),
             (&Self::Bool(ref l), &Self::Bool(ref r)) => Some(l.cmp(r)),
-            (&Self::Tuple(ref l), &Self::Tuple(ref r)) | (&Self::Vec(ref l), &Self::Vec(ref r)) => {
-                iter::zip(l, r)
-                    .map(|(li, ri)| Self::partial_cmp(tcx, cmp_type, li, ri))
-                    .find(|r| r.map_or(true, |o| o != Ordering::Equal))
-                    .unwrap_or_else(|| Some(l.len().cmp(&r.len())))
-            }
+            (&Self::Tuple(ref l), &Self::Tuple(ref r)) | (&Self::Vec(ref l), &Self::Vec(ref r)) => iter::zip(l, r)
+                .map(|(li, ri)| Self::partial_cmp(tcx, cmp_type, li, ri))
+                .find(|r| r.map_or(true, |o| o != Ordering::Equal))
+                .unwrap_or_else(|| Some(l.len().cmp(&r.len()))),
             (&Self::Repeat(ref lv, ref ls), &Self::Repeat(ref rv, ref rs)) => {
                 match Self::partial_cmp(tcx, cmp_type, lv, rv) {
                     Some(Equal) => Some(ls.cmp(rs)),
@@ -157,6 +155,27 @@ pub fn partial_cmp(tcx: TyCtxt<'_>, cmp_type: Ty<'_>, left: &Self, right: &Self)
             _ => None,
         }
     }
+
+    /// Returns the integer value or `None` if `self` or `val_type` is not integer type.
+    pub fn int_value(&self, cx: &LateContext<'_>, val_type: Ty<'_>) -> Option<FullInt> {
+        if let Constant::Int(const_int) = *self {
+            match *val_type.kind() {
+                ty::Int(ity) => Some(FullInt::S(sext(cx.tcx, const_int, ity))),
+                ty::Uint(_) => Some(FullInt::U(const_int)),
+                _ => None,
+            }
+        } else {
+            None
+        }
+    }
+
+    #[must_use]
+    pub fn peel_refs(mut self) -> Self {
+        while let Constant::Ref(r) = self {
+            self = *r;
+        }
+        self
+    }
 }
 
 /// Parses a `LitKind` to a `Constant`.
@@ -204,6 +223,52 @@ pub fn constant_simple<'tcx>(
     constant(lcx, typeck_results, e).and_then(|(cst, res)| if res { None } else { Some(cst) })
 }
 
+pub fn constant_full_int<'tcx>(
+    lcx: &LateContext<'tcx>,
+    typeck_results: &ty::TypeckResults<'tcx>,
+    e: &Expr<'_>,
+) -> Option<FullInt> {
+    constant_simple(lcx, typeck_results, e)?.int_value(lcx, typeck_results.expr_ty(e))
+}
+
+#[derive(Copy, Clone, Debug, Eq)]
+pub enum FullInt {
+    S(i128),
+    U(u128),
+}
+
+impl PartialEq for FullInt {
+    #[must_use]
+    fn eq(&self, other: &Self) -> bool {
+        self.cmp(other) == Ordering::Equal
+    }
+}
+
+impl PartialOrd for FullInt {
+    #[must_use]
+    fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
+        Some(self.cmp(other))
+    }
+}
+
+impl Ord for FullInt {
+    #[must_use]
+    fn cmp(&self, other: &Self) -> Ordering {
+        use FullInt::{S, U};
+
+        fn cmp_s_u(s: i128, u: u128) -> Ordering {
+            u128::try_from(s).map_or(Ordering::Less, |x| x.cmp(&u))
+        }
+
+        match (*self, *other) {
+            (S(s), S(o)) => s.cmp(&o),
+            (U(s), U(o)) => s.cmp(&o),
+            (S(s), U(o)) => cmp_s_u(s, o),
+            (U(s), S(o)) => cmp_s_u(o, s).reverse(),
+        }
+    }
+}
+
 /// Creates a `ConstEvalLateContext` from the given `LateContext` and `TypeckResults`.
 pub fn constant_context<'a, 'tcx>(
     lcx: &'a LateContext<'tcx>,
@@ -231,33 +296,39 @@ impl<'a, 'tcx> ConstEvalLateContext<'a, 'tcx> {
     pub fn expr(&mut self, e: &Expr<'_>) -> Option<Constant> {
         match e.kind {
             ExprKind::Path(ref qpath) => self.fetch_path(qpath, e.hir_id, self.typeck_results.expr_ty(e)),
-            ExprKind::Block(ref block, _) => self.block(block),
-            ExprKind::Lit(ref lit) => Some(lit_to_constant(&lit.node, self.typeck_results.expr_ty_opt(e))),
-            ExprKind::Array(ref vec) => self.multi(vec).map(Constant::Vec),
-            ExprKind::Tup(ref tup) => self.multi(tup).map(Constant::Tuple),
-            ExprKind::Repeat(ref value, _) => {
+            ExprKind::Block(block, _) => self.block(block),
+            ExprKind::Lit(ref lit) => {
+                if is_direct_expn_of(e.span, "cfg").is_some() {
+                    None
+                } else {
+                    Some(lit_to_constant(&lit.node, self.typeck_results.expr_ty_opt(e)))
+                }
+            },
+            ExprKind::Array(vec) => self.multi(vec).map(Constant::Vec),
+            ExprKind::Tup(tup) => self.multi(tup).map(Constant::Tuple),
+            ExprKind::Repeat(value, _) => {
                 let n = match self.typeck_results.expr_ty(e).kind() {
                     ty::Array(_, n) => n.try_eval_usize(self.lcx.tcx, self.lcx.param_env)?,
                     _ => span_bug!(e.span, "typeck error"),
                 };
                 self.expr(value).map(|v| Constant::Repeat(Box::new(v), n))
             },
-            ExprKind::Unary(op, ref operand) => self.expr(operand).and_then(|o| match op {
+            ExprKind::Unary(op, operand) => self.expr(operand).and_then(|o| match op {
                 UnOp::Not => self.constant_not(&o, self.typeck_results.expr_ty(e)),
                 UnOp::Neg => self.constant_negate(&o, self.typeck_results.expr_ty(e)),
                 UnOp::Deref => Some(if let Constant::Ref(r) = o { *r } else { o }),
             }),
-            ExprKind::If(ref cond, ref then, ref otherwise) => self.ifthenelse(cond, then, *otherwise),
-            ExprKind::Binary(op, ref left, ref right) => self.binop(op, left, right),
-            ExprKind::Call(ref callee, ref args) => {
+            ExprKind::If(cond, then, ref otherwise) => self.ifthenelse(cond, then, *otherwise),
+            ExprKind::Binary(op, left, right) => self.binop(op, left, right),
+            ExprKind::Call(callee, args) => {
                 // We only handle a few const functions for now.
                 if_chain! {
                     if args.is_empty();
                     if let ExprKind::Path(qpath) = &callee.kind;
                     let res = self.typeck_results.qpath_res(qpath, callee.hir_id);
                     if let Some(def_id) = res.opt_def_id();
-                    let def_path: Vec<_> = self.lcx.get_def_path(def_id).into_iter().map(Symbol::as_str).collect();
-                    let def_path: Vec<&str> = def_path.iter().take(4).map(|s| &**s).collect();
+                    let def_path = self.lcx.get_def_path(def_id);
+                    let def_path: Vec<&str> = def_path.iter().take(4).map(Symbol::as_str).collect();
                     if let ["core", "num", int_impl, "max_value"] = *def_path;
                     then {
                        let value = match int_impl {
@@ -275,8 +346,8 @@ pub fn expr(&mut self, e: &Expr<'_>) -> Option<Constant> {
                     }
                 }
             },
-            ExprKind::Index(ref arr, ref index) => self.index(arr, index),
-            ExprKind::AddrOf(_, _, ref inner) => self.expr(inner).map(|r| Constant::Ref(Box::new(r))),
+            ExprKind::Index(arr, index) => self.index(arr, index),
+            ExprKind::AddrOf(_, _, inner) => self.expr(inner).map(|r| Constant::Ref(Box::new(r))),
             // TODO: add other expressions.
             _ => None,
         }
@@ -325,7 +396,7 @@ fn multi(&mut self, vec: &[Expr<'_>]) -> Option<Vec<Constant>> {
         vec.iter().map(|elem| self.expr(elem)).collect::<Option<_>>()
     }
 
-    /// Lookup a possibly constant expression from a `ExprKind::Path`.
+    /// Lookup a possibly constant expression from an `ExprKind::Path`.
     fn fetch_path(&mut self, qpath: &QPath<'_>, id: HirId, ty: Ty<'tcx>) -> Option<Constant> {
         let res = self.typeck_results.qpath_res(qpath, id);
         match res {
@@ -342,16 +413,15 @@ fn fetch_path(&mut self, qpath: &QPath<'_>, id: HirId, ty: Ty<'tcx>) -> Option<C
                     .tcx
                     .const_eval_resolve(
                         self.param_env,
-                        ty::Unevaluated {
-                            def: ty::WithOptConstParam::unknown(def_id),
+                        ty::Unevaluated::new(
+                            ty::WithOptConstParam::unknown(def_id),
                             substs,
-                            promoted: None,
-                        },
+                        ),
                         None,
                     )
                     .ok()
                     .map(|val| rustc_middle::ty::Const::from_value(self.lcx.tcx, val, ty))?;
-                let result = miri_to_const(&result);
+                let result = miri_to_const(result);
                 if result.is_some() {
                     self.needed_resolution = true;
                 }