Add new lint `if_then_panic`

[rust.git] / clippy_utils / src / consts.rs

diff --git a/clippy_utils/src/consts.rs b/clippy_utils/src/consts.rs
index 802c01055a68c84d68dd4307c841c6b67bcfa334..8bf31807d55d1441d74e503a42e29334aee365f0 100644 (file)
--- a/clippy_utils/src/consts.rs
+++ b/clippy_utils/src/consts.rs
@@ -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;
@@ -15,6 +15,7 @@
 use std::cmp::Ordering::{self, Equal};
 use std::convert::TryInto;
 use std::hash::{Hash, Hasher};
+use std::iter;
 
 /// A `LitKind`-like enum to fold constant `Expr`s into.
 #[derive(Debug, Clone)]
@@ -139,9 +140,7 @@ 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)) => l
-                .iter()
-                .zip(r.iter())
+            (&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()))),
@@ -230,25 +229,31 @@ 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();
@@ -274,8 +279,8 @@ 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,
         }
@@ -324,7 +329,7 @@ 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 {
@@ -341,14 +346,12 @@ fn fetch_path(&mut self, qpath: &QPath<'_>, id: HirId, ty: Ty<'tcx>) -> Option<C
                     .tcx
                     .const_eval_resolve(
                         self.param_env,
-                        ty::WithOptConstParam::unknown(def_id),
-                        substs,
-                        None,
+                        ty::Unevaluated::new(ty::WithOptConstParam::unknown(def_id), substs),
                         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;
                 }