use hir::def::*;
use ty::{self, TyCtxt};
use lint;
-use util::nodemap::NodeMap;
+use util::nodemap::{NodeMap, NodeSet};
use std::{fmt, usize};
use std::io::prelude::*;
#[derive(Copy, Clone, Debug)]
struct LocalInfo {
id: NodeId,
- name: ast::Name
+ name: ast::Name,
+ is_shorthand: bool,
}
#[derive(Copy, Clone, Debug)]
}
}
+ fn variable_is_shorthand(&self, var: Variable) -> bool {
+ match self.var_kinds[var.get()] {
+ Local(LocalInfo { is_shorthand, .. }) => is_shorthand,
+ Arg(..) | CleanExit => false
+ }
+ }
+
fn set_captures(&mut self, node_id: NodeId, cs: Vec<CaptureInfo>) {
self.capture_info_map.insert(node_id, Rc::new(cs));
}
let name = path1.node;
ir.add_live_node_for_node(p_id, VarDefNode(sp));
ir.add_variable(Local(LocalInfo {
- id: p_id,
- name,
+ id: p_id,
+ name,
+ is_shorthand: false,
}));
});
intravisit::walk_local(ir, local);
fn visit_arm<'a, 'tcx>(ir: &mut IrMaps<'a, 'tcx>, arm: &'tcx hir::Arm) {
for pat in &arm.pats {
+ // for struct patterns, take note of which fields used shorthand (`x`
+ // rather than `x: x`)
+ //
+ // FIXME: according to the rust-lang-nursery/rustc-guide book and
+ // librustc/README.md, `NodeId`s are to be phased out in favor of
+ // `HirId`s; however, we need to match the signature of `each_binding`,
+ // which uses `NodeIds`.
+ let mut shorthand_field_ids = NodeSet();
+ if let hir::PatKind::Struct(_, ref fields, _) = pat.node {
+ for field in fields {
+ if field.node.is_shorthand {
+ shorthand_field_ids.insert(field.node.pat.id);
+ }
+ }
+ }
+
pat.each_binding(|bm, p_id, sp, path1| {
debug!("adding local variable {} from match with bm {:?}",
p_id, bm);
ir.add_live_node_for_node(p_id, VarDefNode(sp));
ir.add_variable(Local(LocalInfo {
id: p_id,
- name,
+ name: name,
+ is_shorthand: shorthand_field_ids.contains(&p_id)
}));
})
}
self.assigned_on_exit(ln, var).is_some()
};
+ let suggest_underscore_msg = format!("consider using `_{}` instead",
+ name);
if is_assigned {
- self.ir.tcx.lint_node_note(lint::builtin::UNUSED_VARIABLES, id, sp,
- &format!("variable `{}` is assigned to, but never used",
- name),
- &format!("to avoid this warning, consider using `_{}` instead",
- name));
+ self.ir.tcx
+ .lint_node_note(lint::builtin::UNUSED_VARIABLES, id, sp,
+ &format!("variable `{}` is assigned to, but never used",
+ name),
+ &suggest_underscore_msg);
} else if name != "self" {
- self.ir.tcx.lint_node_note(lint::builtin::UNUSED_VARIABLES, id, sp,
- &format!("unused variable: `{}`", name),
- &format!("to avoid this warning, consider using `_{}` instead",
- name));
+ let msg = format!("unused variable: `{}`", name);
+ let mut err = self.ir.tcx
+ .struct_span_lint_node(lint::builtin::UNUSED_VARIABLES, id, sp, &msg);
+ if self.ir.variable_is_shorthand(var) {
+ err.span_suggestion(sp, "try ignoring the field",
+ format!("{}: _", name));
+ } else {
+ err.span_suggestion_short(sp, &suggest_underscore_msg,
+ format!("_{}", name));
+ }
+ err.emit()
}
}
true
#![allow(non_snake_case)]
use hir::def_id::DefId;
-use hir::ItemLocalId;
+use hir::{HirId, ItemLocalId};
use syntax::ast;
pub use rustc_data_structures::fx::FxHashMap;
pub type NodeMap<T> = FxHashMap<ast::NodeId, T>;
pub type DefIdMap<T> = FxHashMap<DefId, T>;
+pub type HirIdMap<T> = FxHashMap<HirId, T>;
pub type ItemLocalMap<T> = FxHashMap<ItemLocalId, T>;
pub type NodeSet = FxHashSet<ast::NodeId>;
pub type DefIdSet = FxHashSet<DefId>;
+pub type HirIdSet = FxHashSet<HirId>;
pub type ItemLocalSet = FxHashSet<ItemLocalId>;
pub fn NodeMap<T>() -> NodeMap<T> { FxHashMap() }
--- /dev/null
+// Copyright 2018 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+// must-compile-successfully
+
+#![warn(unused)] // UI tests pass `-A unused` (#43896)
+
+struct SoulHistory {
+ corridors_of_light: usize,
+ hours_are_suns: bool,
+ endless_and_singing: bool
+}
+
+fn main() {
+ let i_think_continually = 2;
+ let who_from_the_womb_remembered = SoulHistory {
+ corridors_of_light: 5,
+ hours_are_suns: true,
+ endless_and_singing: true
+ };
+
+ if let SoulHistory { corridors_of_light,
+ mut hours_are_suns,
+ endless_and_singing: true } = who_from_the_womb_remembered {
+ hours_are_suns = false;
+ }
+}
--- /dev/null
+warning: unused variable: `i_think_continually`
+ --> $DIR/issue-47390-unused-variable-in-struct-pattern.rs:22:9
+ |
+22 | let i_think_continually = 2;
+ | ^^^^^^^^^^^^^^^^^^^ help: consider using `_i_think_continually` instead
+ |
+note: lint level defined here
+ --> $DIR/issue-47390-unused-variable-in-struct-pattern.rs:13:9
+ |
+13 | #![warn(unused)] // UI tests pass `-A unused` (#43896)
+ | ^^^^^^
+ = note: #[warn(unused_variables)] implied by #[warn(unused)]
+
+warning: unused variable: `corridors_of_light`
+ --> $DIR/issue-47390-unused-variable-in-struct-pattern.rs:29:26
+ |
+29 | if let SoulHistory { corridors_of_light,
+ | ^^^^^^^^^^^^^^^^^^ help: try ignoring the field: `corridors_of_light: _`
+
+warning: variable `hours_are_suns` is assigned to, but never used
+ --> $DIR/issue-47390-unused-variable-in-struct-pattern.rs:30:26
+ |
+30 | mut hours_are_suns,
+ | ^^^^^^^^^^^^^^^^^^
+ |
+ = note: consider using `_hours_are_suns` instead
+
+warning: value assigned to `hours_are_suns` is never read
+ --> $DIR/issue-47390-unused-variable-in-struct-pattern.rs:32:9
+ |
+32 | hours_are_suns = false;
+ | ^^^^^^^^^^^^^^
+ |
+note: lint level defined here
+ --> $DIR/issue-47390-unused-variable-in-struct-pattern.rs:13:9
+ |
+13 | #![warn(unused)] // UI tests pass `-A unused` (#43896)
+ | ^^^^^^
+ = note: #[warn(unused_assignments)] implied by #[warn(unused)]
+
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