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Rollup merge of #30286 - oli-obk:const_error_span, r=nikomatsakis 

previously the error was erased and a `non-const path` error was emitted at the location of the field access instead of at the overflow location (as can be seen in the playground: http://is.gd/EuAF5F )
This commit is contained in:
Manish Goregaokar 2015-12-18 13:43:45 +05:30
parent f963eb2870 88675939d2
commit cb319fc84f
2 changed files with 37 additions and 25 deletions
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44
src/librustc/middle/const_eval.rs
View File

@ -1182,46 +1182,40 @@ pub fn eval_const_expr_partial<'tcx>(tcx: &ty::ctxt<'tcx>,
},
hir::ExprTupField(ref base, index) => {
let base_hint = ty_hint.erase_hint();
if let Ok(c) = eval_const_expr_partial(tcx, base, base_hint, fn_args) {
if let Tuple(tup_id) = c {
if let hir::ExprTup(ref fields) = tcx.map.expect_expr(tup_id).node {
if index.node < fields.len() {
return eval_const_expr_partial(tcx, &fields[index.node], base_hint, fn_args)
} else {
signal!(e, TupleIndexOutOfBounds);
}
let c = try!(eval_const_expr_partial(tcx, base, base_hint, fn_args));
if let Tuple(tup_id) = c {
if let hir::ExprTup(ref fields) = tcx.map.expect_expr(tup_id).node {
if index.node < fields.len() {
return eval_const_expr_partial(tcx, &fields[index.node], base_hint, fn_args)
} else {
unreachable!()
signal!(e, TupleIndexOutOfBounds);
}
} else {
signal!(base, ExpectedConstTuple);
unreachable!()
}
} else {
signal!(base, NonConstPath)
signal!(base, ExpectedConstTuple);
}
}
hir::ExprField(ref base, field_name) => {
let base_hint = ty_hint.erase_hint();
// Get the base expression if it is a struct and it is constant
if let Ok(c) = eval_const_expr_partial(tcx, base, base_hint, fn_args) {
if let Struct(struct_id) = c {
if let hir::ExprStruct(_, ref fields, _) = tcx.map.expect_expr(struct_id).node {
// Check that the given field exists and evaluate it
// if the idents are compared run-pass/issue-19244 fails
if let Some(f) = fields.iter().find(|f| f.name.node
== field_name.node) {
return eval_const_expr_partial(tcx, &*f.expr, base_hint, fn_args)
} else {
signal!(e, MissingStructField);
}
let c = try!(eval_const_expr_partial(tcx, base, base_hint, fn_args));
if let Struct(struct_id) = c {
if let hir::ExprStruct(_, ref fields, _) = tcx.map.expect_expr(struct_id).node {
// Check that the given field exists and evaluate it
// if the idents are compared run-pass/issue-19244 fails
if let Some(f) = fields.iter().find(|f| f.name.node
== field_name.node) {
return eval_const_expr_partial(tcx, &*f.expr, base_hint, fn_args)
} else {
unreachable!()
signal!(e, MissingStructField);
}
} else {
signal!(base, ExpectedConstStruct);
unreachable!()
}
} else {
signal!(base, NonConstPath);
signal!(base, ExpectedConstStruct);
}
}
_ => signal!(e, MiscCatchAll)

18
src/test/compile-fail/const-tup-index-span.rs Normal file
View File

@ -0,0 +1,18 @@
// Copyright 2015 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.
// Test spans of errors
const TUP: (usize,) = 5 << 64;
//~^ ERROR: attempted left shift with overflow [E0250]
const ARR: [i32; TUP.0] = [];
fn main() {
}