rustup https://github.com/rust-lang/rust/pull/68944

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

diff --git a/clippy_lints/src/let_if_seq.rs b/clippy_lints/src/let_if_seq.rs
index f5da2d7803e381254daaaa079093fc6bb77eaafc..d5343852208b87d4d833867580b5229dc9fa2709 100644 (file)
--- a/clippy_lints/src/let_if_seq.rs
+++ b/clippy_lints/src/let_if_seq.rs
@@ -1,11 +1,13 @@
-use crate::utils::{snippet, span_lint_and_then};
+use crate::utils::{higher, qpath_res, snippet, span_lint_and_then};
 use if_chain::if_chain;
-use rustc::hir;
-use rustc::hir::def::Def;
-use rustc::hir::BindingAnnotation;
-use rustc::lint::{LateContext, LateLintPass, LintArray, LintPass};
-use rustc::{declare_lint_pass, declare_tool_lint};
+use rustc::hir::map::Map;
 use rustc_errors::Applicability;
+use rustc_hir as hir;
+use rustc_hir::def::Res;
+use rustc_hir::intravisit;
+use rustc_hir::BindingAnnotation;
+use rustc_lint::{LateContext, LateLintPass};
+use rustc_session::{declare_lint_pass, declare_tool_lint};
 
 declare_clippy_lint! {
     /// **What it does:** Checks for variable declarations immediately followed by a
@@ -55,24 +57,31 @@
 declare_lint_pass!(LetIfSeq => [USELESS_LET_IF_SEQ]);
 
 impl<'a, 'tcx> LateLintPass<'a, 'tcx> for LetIfSeq {
-    fn check_block(&mut self, cx: &LateContext<'a, 'tcx>, block: &'tcx hir::Block) {
+    fn check_block(&mut self, cx: &LateContext<'a, 'tcx>, block: &'tcx hir::Block<'_>) {
         let mut it = block.stmts.iter().peekable();
         while let Some(stmt) = it.next() {
             if_chain! {
                 if let Some(expr) = it.peek();
-                if let hir::StmtKind::Local(ref local) = stmt.node;
-                if let hir::PatKind::Binding(mode, canonical_id, ident, None) = local.pat.node;
-                if let hir::StmtKind::Expr(ref if_) = expr.node;
-                if let hir::ExprKind::If(ref cond, ref then, ref else_) = if_.node;
+                if let hir::StmtKind::Local(ref local) = stmt.kind;
+                if let hir::PatKind::Binding(mode, canonical_id, ident, None) = local.pat.kind;
+                if let hir::StmtKind::Expr(ref if_) = expr.kind;
+                if let Some((ref cond, ref then, ref else_)) = higher::if_block(&if_);
                 if !used_in_expr(cx, canonical_id, cond);
-                if let hir::ExprKind::Block(ref then, _) = then.node;
+                if let hir::ExprKind::Block(ref then, _) = then.kind;
                 if let Some(value) = check_assign(cx, canonical_id, &*then);
                 if !used_in_expr(cx, canonical_id, value);
                 then {
                     let span = stmt.span.to(if_.span);
 
+                    let has_interior_mutability = !cx.tables.node_type(canonical_id).is_freeze(
+                        cx.tcx,
+                        cx.param_env,
+                        span
+                    );
+                    if has_interior_mutability { return; }
+
                     let (default_multi_stmts, default) = if let Some(ref else_) = *else_ {
-                        if let hir::ExprKind::Block(ref else_, _) = else_.node {
+                        if let hir::ExprKind::Block(ref else_, _) = else_.kind {
                             if let Some(default) = check_assign(cx, canonical_id, else_) {
                                 (else_.stmts.len() > 1, default)
                             } else if let Some(ref default) = local.init {
@@ -128,42 +137,44 @@ fn check_block(&mut self, cx: &LateContext<'a, 'tcx>, block: &'tcx hir::Block) {
     }
 }
 
-struct UsedVisitor<'a, 'tcx: 'a> {
+struct UsedVisitor<'a, 'tcx> {
     cx: &'a LateContext<'a, 'tcx>,
     id: hir::HirId,
     used: bool,
 }
 
-impl<'a, 'tcx> hir::intravisit::Visitor<'tcx> for UsedVisitor<'a, 'tcx> {
-    fn visit_expr(&mut self, expr: &'tcx hir::Expr) {
+impl<'a, 'tcx> intravisit::Visitor<'tcx> for UsedVisitor<'a, 'tcx> {
+    type Map = Map<'tcx>;
+
+    fn visit_expr(&mut self, expr: &'tcx hir::Expr<'_>) {
         if_chain! {
-            if let hir::ExprKind::Path(ref qpath) = expr.node;
-            if let Def::Local(local_id) = self.cx.tables.qpath_def(qpath, expr.hir_id);
+            if let hir::ExprKind::Path(ref qpath) = expr.kind;
+            if let Res::Local(local_id) = qpath_res(self.cx, qpath, expr.hir_id);
             if self.id == local_id;
             then {
                 self.used = true;
                 return;
             }
         }
-        hir::intravisit::walk_expr(self, expr);
+        intravisit::walk_expr(self, expr);
     }
-    fn nested_visit_map<'this>(&'this mut self) -> hir::intravisit::NestedVisitorMap<'this, 'tcx> {
-        hir::intravisit::NestedVisitorMap::None
+    fn nested_visit_map(&mut self) -> intravisit::NestedVisitorMap<Self::Map> {
+        intravisit::NestedVisitorMap::None
     }
 }
 
 fn check_assign<'a, 'tcx>(
     cx: &LateContext<'a, 'tcx>,
     decl: hir::HirId,
-    block: &'tcx hir::Block,
-) -> Option<&'tcx hir::Expr> {
+    block: &'tcx hir::Block<'_>,
+) -> Option<&'tcx hir::Expr<'tcx>> {
     if_chain! {
         if block.expr.is_none();
         if let Some(expr) = block.stmts.iter().last();
-        if let hir::StmtKind::Semi(ref expr) = expr.node;
-        if let hir::ExprKind::Assign(ref var, ref value) = expr.node;
-        if let hir::ExprKind::Path(ref qpath) = var.node;
-        if let Def::Local(local_id) = cx.tables.qpath_def(qpath, var.hir_id);
+        if let hir::StmtKind::Semi(ref expr) = expr.kind;
+        if let hir::ExprKind::Assign(ref var, ref value, _) = expr.kind;
+        if let hir::ExprKind::Path(ref qpath) = var.kind;
+        if let Res::Local(local_id) = qpath_res(cx, qpath, var.hir_id);
         if decl == local_id;
         then {
             let mut v = UsedVisitor {
@@ -173,7 +184,7 @@ fn check_assign<'a, 'tcx>(
             };
 
             for s in block.stmts.iter().take(block.stmts.len()-1) {
-                hir::intravisit::walk_stmt(&mut v, s);
+                intravisit::walk_stmt(&mut v, s);
 
                 if v.used {
                     return None;
@@ -187,8 +198,8 @@ fn check_assign<'a, 'tcx>(
     None
 }
 
-fn used_in_expr<'a, 'tcx: 'a>(cx: &LateContext<'a, 'tcx>, id: hir::HirId, expr: &'tcx hir::Expr) -> bool {
+fn used_in_expr<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, id: hir::HirId, expr: &'tcx hir::Expr<'_>) -> bool {
     let mut v = UsedVisitor { cx, id, used: false };
-    hir::intravisit::walk_expr(&mut v, expr);
+    intravisit::walk_expr(&mut v, expr);
     v.used
 }