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Auto merge of #35015 - petrochenkov:forearg, r=nikomatsakis 

Properly enforce the "patterns aren't allowed in foreign functions" rule

Cases like `arg @ PATTERN` or `mut arg` were missing.
Apply the same rule to function pointer types.

Closes https://github.com/rust-lang/rust/issues/35203
[breaking-change], no breakage in sane code is expected though
r? @nikomatsakis

This is somewhat related to https://github.com/rust-lang/rfcs/pull/1685 (cc @matklad).
The goal is to eventually support full pattern syntax where it makes sense (function body may present) and to support *only* the following forms - `TYPE`, `ident: TYPE`, `_: TYPE` - where patterns don't make sense (function body doesn't present), i.e. in foreign functions and function pointer types.
This commit is contained in:
bors 2016-08-03 22:56:33 -07:00 committed by GitHub
parent 40f3ee2a01 5c88efc0da
commit 271d048523
5 changed files with 114 additions and 47 deletions
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47
src/librustc_passes/ast_validation.rs
View File

@ -55,6 +55,17 @@ impl<'a> AstValidator<'a> {
err.emit();
}
}
fn check_decl_no_pat<ReportFn: Fn(Span, bool)>(&self, decl: &FnDecl, report_err: ReportFn) {
for arg in &decl.inputs {
match arg.pat.node {
PatKind::Ident(BindingMode::ByValue(Mutability::Immutable), _, None) |
PatKind::Wild => {}
PatKind::Ident(..) => report_err(arg.pat.span, true),
_ => report_err(arg.pat.span, false),
}
}
}
}
impl<'a> Visitor for AstValidator<'a> {
@ -82,6 +93,23 @@ impl<'a> Visitor for AstValidator<'a> {
visit::walk_expr(self, expr)
}
fn visit_ty(&mut self, ty: &Ty) {
match ty.node {
TyKind::BareFn(ref bfty) => {
self.check_decl_no_pat(&bfty.decl, |span, _| {
let mut err = struct_span_err!(self.session, span, E0561,
"patterns aren't allowed in function pointer types");
err.span_note(span, "this is a recent error, see \
issue #35203 for more details");
err.emit();
});
}
_ => {}
}
visit::walk_ty(self, ty)
}
fn visit_path(&mut self, path: &Path, id: NodeId) {
if path.global && path.segments.len() > 0 {
let ident = path.segments[0].identifier;
@ -135,6 +163,25 @@ impl<'a> Visitor for AstValidator<'a> {
visit::walk_item(self, item)
}
fn visit_foreign_item(&mut self, fi: &ForeignItem) {
match fi.node {
ForeignItemKind::Fn(ref decl, _) => {
self.check_decl_no_pat(decl, |span, is_recent| {
let mut err = struct_span_err!(self.session, span, E0130,
"patterns aren't allowed in foreign function declarations");
if is_recent {
err.span_note(span, "this is a recent error, see \
issue #35203 for more details");
}
err.emit();
});
}
ForeignItemKind::Static(..) => {}
}
visit::walk_foreign_item(self, fi)
}
fn visit_variant_data(&mut self, vdata: &VariantData, _: Ident,
_: &Generics, _: NodeId, span: Span) {
if vdata.fields().is_empty() {

34
src/librustc_passes/diagnostics.rs
View File

@ -49,6 +49,39 @@ match 5u32 {
```
"##,
E0130: r##"
You declared a pattern as an argument in a foreign function declaration.
Erroneous code example:
```compile_fail
extern {
fn foo((a, b): (u32, u32)); // error: patterns aren't allowed in foreign
// function declarations
}
```
Please replace the pattern argument with a regular one. Example:
```
struct SomeStruct {
a: u32,
b: u32,
}
extern {
fn foo(s: SomeStruct); // ok!
}
```
Or:
```
extern {
fn foo(a: (u32, u32)); // ok!
}
```
"##,
E0161: r##"
A value was moved. However, its size was not known at compile time, and only
values of a known size can be moved.
@ -187,4 +220,5 @@ pub impl Foo for Bar {
register_diagnostics! {
E0472, // asm! is unsupported on this target
E0561, // patterns aren't allowed in function pointer types
}

17
src/librustc_typeck/collect.rs
View File

@ -60,8 +60,6 @@ There are some shortcomings in this design:
use astconv::{AstConv, ast_region_to_region, Bounds, PartitionedBounds, partition_bounds};
use lint;
use hir::def::Def;
use hir::def_id::DefId;
use constrained_type_params as ctp;
use middle::lang_items::SizedTraitLangItem;
use middle::const_val::ConstVal;
@ -74,7 +72,6 @@ use rustc::ty::{VariantKind};
use rustc::ty::util::IntTypeExt;
use rscope::*;
use rustc::dep_graph::DepNode;
use rustc::hir::map as hir_map;
use util::common::{ErrorReported, MemoizationMap};
use util::nodemap::{NodeMap, FnvHashMap};
use {CrateCtxt, write_ty_to_tcx};
@ -91,9 +88,9 @@ use syntax::parse::token::keywords;
use syntax::ptr::P;
use syntax_pos::Span;
use rustc::hir::{self, PatKind};
use rustc::hir::intravisit;
use rustc::hir::print as pprust;
use rustc::hir::{self, intravisit, map as hir_map, print as pprust};
use rustc::hir::def::Def;
use rustc::hir::def_id::DefId;
///////////////////////////////////////////////////////////////////////////
// Main entry point
@ -2144,14 +2141,6 @@ fn compute_type_scheme_of_foreign_fn_decl<'a, 'tcx>(
abi: abi::Abi)
-> ty::TypeScheme<'tcx>
{
for i in &decl.inputs {
match i.pat.node {
PatKind::Binding(..) | PatKind::Wild => {}
_ => span_err!(ccx.tcx.sess, i.pat.span, E0130,
"patterns aren't allowed in foreign function declarations")
}
}
let ty_generics = ty_generics_for_fn(ccx, ast_generics, &ty::Generics::empty());
let rb = BindingRscope::new();

33
src/librustc_typeck/diagnostics.rs
View File

@ -1800,39 +1800,6 @@ Please also verify that this wasn't because of a name-clash and rename the type
parameter if so.
"##,
E0130: r##"
You declared a pattern as an argument in a foreign function declaration.
Erroneous code example:
```compile_fail
extern {
fn foo((a, b): (u32, u32)); // error: patterns aren't allowed in foreign
// function declarations
}
```
Please replace the pattern argument with a regular one. Example:
```
struct SomeStruct {
a: u32,
b: u32,
}
extern {
fn foo(s: SomeStruct); // ok!
}
```
Or:
```
extern {
fn foo(a: (u32, u32)); // ok!
}
```
"##,
E0131: r##"
It is not possible to define `main` with type parameters, or even with function
parameters. When `main` is present, it must take no arguments and return `()`.

30
src/test/compile-fail/no-patterns-in-args.rs Normal file
View File

@ -0,0 +1,30 @@
// Copyright 2016 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.
extern {
fn f1(mut arg: u8); //~ ERROR patterns aren't allowed in foreign function declarations
//~^ NOTE this is a recent error
fn f2(&arg: u8); //~ ERROR patterns aren't allowed in foreign function declarations
fn f3(arg @ _: u8); //~ ERROR patterns aren't allowed in foreign function declarations
//~^ NOTE this is a recent error
fn g1(arg: u8); // OK
fn g2(_: u8); // OK
// fn g3(u8); // Not yet
}
type A1 = fn(mut arg: u8); //~ ERROR patterns aren't allowed in function pointer types
//~^ NOTE this is a recent error
type A2 = fn(&arg: u8); //~ ERROR patterns aren't allowed in function pointer types
//~^ NOTE this is a recent error
type B1 = fn(arg: u8); // OK
type B2 = fn(_: u8); // OK
type B3 = fn(u8); // OK
fn main() {}