44440e5c18
fmt::Show is for debugging, and can and should be implemented for
all public types. This trait is used with `{:?}` syntax. There still
exists #[derive(Show)].
fmt::String is for types that faithfully be represented as a String.
Because of this, there is no way to derive fmt::String, all
implementations must be purposeful. It is used by the default format
syntax, `{}`.
This will break most instances of `{}`, since that now requires the type
to impl fmt::String. In most cases, replacing `{}` with `{:?}` is the
correct fix. Types that were being printed specifically for users should
receive a fmt::String implementation to fix this.
Part of #20013
[breaking-change]
102 lines
3.2 KiB
Rust
102 lines
3.2 KiB
Rust
// Copyright 2014 The Rust Project Developers. See the COPYRIGHT
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// file at the top-level directory of this distribution and at
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// http://rust-lang.org/COPYRIGHT.
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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// Checks that all rvalues in a crate have statically known size. check_crate
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// is the public starting point.
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use middle::expr_use_visitor as euv;
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use middle::mem_categorization as mc;
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use middle::ty::ParameterEnvironment;
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use middle::ty;
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use util::ppaux::ty_to_string;
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use syntax::ast;
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use syntax::codemap::Span;
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use syntax::visit;
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pub fn check_crate(tcx: &ty::ctxt,
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krate: &ast::Crate) {
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let mut rvcx = RvalueContext { tcx: tcx };
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visit::walk_crate(&mut rvcx, krate);
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}
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struct RvalueContext<'a, 'tcx: 'a> {
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tcx: &'a ty::ctxt<'tcx>,
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}
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impl<'a, 'tcx, 'v> visit::Visitor<'v> for RvalueContext<'a, 'tcx> {
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fn visit_fn(&mut self,
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fk: visit::FnKind<'v>,
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fd: &'v ast::FnDecl,
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b: &'v ast::Block,
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s: Span,
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fn_id: ast::NodeId) {
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{
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let param_env = ParameterEnvironment::for_item(self.tcx, fn_id);
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let mut delegate = RvalueContextDelegate { tcx: self.tcx, param_env: ¶m_env };
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let mut euv = euv::ExprUseVisitor::new(&mut delegate, ¶m_env);
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euv.walk_fn(fd, b);
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}
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visit::walk_fn(self, fk, fd, b, s)
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}
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}
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struct RvalueContextDelegate<'a, 'tcx: 'a> {
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tcx: &'a ty::ctxt<'tcx>,
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param_env: &'a ty::ParameterEnvironment<'a,'tcx>,
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}
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impl<'a, 'tcx> euv::Delegate<'tcx> for RvalueContextDelegate<'a, 'tcx> {
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fn consume(&mut self,
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_: ast::NodeId,
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span: Span,
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cmt: mc::cmt<'tcx>,
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_: euv::ConsumeMode) {
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debug!("consume; cmt: {:?}; type: {}", *cmt, ty_to_string(self.tcx, cmt.ty));
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if !ty::type_is_sized(self.param_env, span, cmt.ty) {
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span_err!(self.tcx.sess, span, E0161,
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"cannot move a value of type {0}: the size of {0} cannot be statically determined",
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ty_to_string(self.tcx, cmt.ty));
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}
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}
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fn matched_pat(&mut self,
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_matched_pat: &ast::Pat,
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_cmt: mc::cmt,
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_mode: euv::MatchMode) {}
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fn consume_pat(&mut self,
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_consume_pat: &ast::Pat,
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_cmt: mc::cmt,
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_mode: euv::ConsumeMode) {
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}
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fn borrow(&mut self,
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_borrow_id: ast::NodeId,
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_borrow_span: Span,
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_cmt: mc::cmt,
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_loan_region: ty::Region,
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_bk: ty::BorrowKind,
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_loan_cause: euv::LoanCause) {
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}
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fn decl_without_init(&mut self,
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_id: ast::NodeId,
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_span: Span) {
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}
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fn mutate(&mut self,
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_assignment_id: ast::NodeId,
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_assignment_span: Span,
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_assignee_cmt: mc::cmt,
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_mode: euv::MutateMode) {
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}
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}
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