X-Git-Url: https://git.lizzy.rs/?a=blobdiff_plain;f=clippy_lints%2Fsrc%2Futils%2Fmod.rs;h=49d9de35e182160155f06edf5bae6864c7142e2c;hb=52408f5b7d0392b008d647c5414e45dad4c4f5fd;hp=bcb443158397e2b36e7bc9b5f66c0a4e70541b33;hpb=e3c4ffd4aa9a4ec39547c4a5a9715173d4a5f43d;p=rust.git

diff --git a/clippy_lints/src/utils/mod.rs b/clippy_lints/src/utils/mod.rs
index bcb44315839..49d9de35e18 100644
--- a/clippy_lints/src/utils/mod.rs
+++ b/clippy_lints/src/utils/mod.rs
@@ -47,6 +47,7 @@
 use syntax::source_map::{Span, DUMMY_SP};
 use syntax::symbol::{kw, Symbol};
 
+use crate::consts::{constant, Constant};
 use crate::reexport::*;
 
 /// Returns `true` if the two spans come from differing expansions (i.e., one is
@@ -272,6 +273,19 @@ pub fn path_to_res(cx: &LateContext<'_, '_>, path: &[&str]) -> Option<(def::Res)
     }
 }
 
+pub fn qpath_res(cx: &LateContext<'_, '_>, qpath: &hir::QPath, id: hir::HirId) -> Res {
+    match qpath {
+        hir::QPath::Resolved(_, path) => path.res,
+        hir::QPath::TypeRelative(..) => {
+            if cx.tcx.has_typeck_tables(id.owner_def_id()) {
+                cx.tcx.typeck_tables_of(id.owner_def_id()).qpath_res(qpath, id)
+            } else {
+                Res::Err
+            }
+        },
+    }
+}
+
 /// Convenience function to get the `DefId` of a trait by path.
 /// It could be a trait or trait alias.
 pub fn get_trait_def_id(cx: &LateContext<'_, '_>, path: &[&str]) -> Option<DefId> {
@@ -669,6 +683,24 @@ fn inner(ty: Ty<'_>, depth: usize) -> (Ty<'_>, usize) {
     inner(ty, 0)
 }
 
+/// Checks whether the given expression is a constant integer of the given value.
+/// unlike `is_integer_literal`, this version does const folding
+pub fn is_integer_const(cx: &LateContext<'_, '_>, e: &Expr, value: u128) -> bool {
+    if is_integer_literal(e, value) {
+        return true;
+    }
+    let map = cx.tcx.hir();
+    let parent_item = map.get_parent_item(e.hir_id);
+    if let Some((Constant::Int(v), _)) = map
+        .maybe_body_owned_by(parent_item)
+        .and_then(|body_id| constant(cx, cx.tcx.body_tables(body_id), e))
+    {
+        value == v
+    } else {
+        false
+    }
+}
+
 /// Checks whether the given expression is a constant literal of the given value.
 pub fn is_integer_literal(expr: &Expr, value: u128) -> bool {
     // FIXME: use constant folding
@@ -1136,3 +1168,47 @@ pub fn match_def_path<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, did: DefId, syms: &[
     let path = cx.get_def_path(did);
     path.len() == syms.len() && path.into_iter().zip(syms.iter()).all(|(a, &b)| a.as_str() == b)
 }
+
+/// Returns the list of condition expressions and the list of blocks in a
+/// sequence of `if/else`.
+/// E.g., this returns `([a, b], [c, d, e])` for the expression
+/// `if a { c } else if b { d } else { e }`.
+pub fn if_sequence(mut expr: &Expr) -> (SmallVec<[&Expr; 1]>, SmallVec<[&Block; 1]>) {
+    let mut conds = SmallVec::new();
+    let mut blocks: SmallVec<[&Block; 1]> = SmallVec::new();
+
+    while let Some((ref cond, ref then_expr, ref else_expr)) = higher::if_block(&expr) {
+        conds.push(&**cond);
+        if let ExprKind::Block(ref block, _) = then_expr.node {
+            blocks.push(block);
+        } else {
+            panic!("ExprKind::If node is not an ExprKind::Block");
+        }
+
+        if let Some(ref else_expr) = *else_expr {
+            expr = else_expr;
+        } else {
+            break;
+        }
+    }
+
+    // final `else {..}`
+    if !blocks.is_empty() {
+        if let ExprKind::Block(ref block, _) = expr.node {
+            blocks.push(&**block);
+        }
+    }
+
+    (conds, blocks)
+}
+
+pub fn parent_node_is_if_expr<'a, 'b>(expr: &Expr, cx: &LateContext<'a, 'b>) -> bool {
+    let parent_id = cx.tcx.hir().get_parent_node(expr.hir_id);
+    let parent_node = cx.tcx.hir().get(parent_id);
+
+    match parent_node {
+        rustc::hir::Node::Expr(e) => higher::if_block(&e).is_some(),
+        rustc::hir::Node::Arm(e) => higher::if_block(&e.body).is_some(),
+        _ => false,
+    }
+}