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Added fully elaborated type label for inferred arguments.

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This commit is contained in:
David Wood 2018-07-23 13:09:30 +02:00
parent 41ce2e9dd2
commit 53dda8e915
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GPG key ID: 01760B4F9F53F154
6 changed files with 112 additions and 16 deletions
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2
src/librustc/infer/error_reporting/need_type_info.rs
View file

@ -74,7 +74,7 @@ impl<'a, 'gcx, 'tcx> Visitor<'gcx> for FindLocalByTypeVisitor<'a, 'gcx, 'tcx> {
impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
fn extract_type_name(&self, ty: &'a Ty<'tcx>) -> String {
pub fn extract_type_name(&self, ty: &'a Ty<'tcx>) -> String {
if let ty::TyInfer(ty::TyVar(ty_vid)) = (*ty).sty {
let ty_vars = self.type_variables.borrow();
if let TypeVariableOrigin::TypeParameterDefinition(_, name) =

4
src/librustc_mir/borrow_check/nll/region_infer/error_reporting/mod.rs
View file

@ -404,9 +404,9 @@ impl<'tcx> RegionInferenceContext<'tcx> {
let counter = &mut 1;
let fr_name = self.give_region_a_name(
infcx.tcx, mir, mir_def_id, fr, counter, &mut diag);
infcx, mir, mir_def_id, fr, counter, &mut diag);
let outlived_fr_name = self.give_region_a_name(
infcx.tcx, mir, mir_def_id, outlived_fr, counter, &mut diag);
infcx, mir, mir_def_id, outlived_fr, counter, &mut diag);
match (category, outlived_fr_is_local, fr_is_local) {
(ConstraintCategory::Return, true, _) => {

68
src/librustc_mir/borrow_check/nll/region_infer/error_reporting/region_name.rs
View file

@ -12,6 +12,7 @@ use borrow_check::nll::region_infer::RegionInferenceContext;
use borrow_check::nll::ToRegionVid;
use rustc::hir;
use rustc::hir::def_id::DefId;
use rustc::infer::InferCtxt;
use rustc::mir::Mir;
use rustc::ty::subst::{Substs, UnpackedKind};
use rustc::ty::{self, RegionVid, Ty, TyCtxt};
@ -48,7 +49,7 @@ impl<'tcx> RegionInferenceContext<'tcx> {
/// and then return the name `'1` for us to use.
crate fn give_region_a_name(
&self,
tcx: TyCtxt<'_, '_, 'tcx>,
infcx: &InferCtxt<'_, '_, 'tcx>,
mir: &Mir<'tcx>,
mir_def_id: DefId,
fr: RegionVid,
@ -59,17 +60,18 @@ impl<'tcx> RegionInferenceContext<'tcx> {
assert!(self.universal_regions.is_universal_region(fr));
self.give_name_from_error_region(tcx, mir_def_id, fr, counter, diag)
self.give_name_from_error_region(infcx.tcx, mir_def_id, fr, counter, diag)
.or_else(|| {
self.give_name_if_anonymous_region_appears_in_arguments(
tcx, mir, mir_def_id, fr, counter, diag)
infcx, mir, mir_def_id, fr, counter, diag)
})
.or_else(|| {
self.give_name_if_anonymous_region_appears_in_upvars(
tcx, mir, fr, counter, diag)
infcx.tcx, mir, fr, counter, diag)
})
.or_else(|| {
self.give_name_if_anonymous_region_appears_in_output(tcx, mir, fr, counter, diag)
self.give_name_if_anonymous_region_appears_in_output(
infcx.tcx, mir, fr, counter, diag)
})
.unwrap_or_else(|| span_bug!(mir.span, "can't make a name for free region {:?}", fr))
}
@ -130,7 +132,7 @@ impl<'tcx> RegionInferenceContext<'tcx> {
/// ```
fn give_name_if_anonymous_region_appears_in_arguments(
&self,
tcx: TyCtxt<'_, '_, 'tcx>,
infcx: &InferCtxt<'_, '_, 'tcx>,
mir: &Mir<'tcx>,
mir_def_id: DefId,
fr: RegionVid,
@ -138,12 +140,12 @@ impl<'tcx> RegionInferenceContext<'tcx> {
diag: &mut DiagnosticBuilder<'_>,
) -> Option<InternedString> {
let implicit_inputs = self.universal_regions.defining_ty.implicit_inputs();
let argument_index = self.get_argument_index_for_region(tcx, fr)?;
let argument_index = self.get_argument_index_for_region(infcx.tcx, fr)?;
let arg_ty =
self.universal_regions.unnormalized_input_tys[implicit_inputs + argument_index];
if let Some(region_name) = self.give_name_if_we_can_match_hir_ty_from_argument(
tcx,
infcx,
mir_def_id,
fr,
arg_ty,
@ -169,7 +171,7 @@ impl<'tcx> RegionInferenceContext<'tcx> {
fn give_name_if_we_can_match_hir_ty_from_argument(
&self,
tcx: TyCtxt<'_, '_, 'tcx>,
infcx: &InferCtxt<'_, '_, 'tcx>,
mir_def_id: DefId,
needle_fr: RegionVid,
argument_ty: Ty<'tcx>,
@ -177,17 +179,23 @@ impl<'tcx> RegionInferenceContext<'tcx> {
counter: &mut usize,
diag: &mut DiagnosticBuilder<'_>,
) -> Option<InternedString> {
let mir_node_id = tcx.hir.as_local_node_id(mir_def_id)?;
let fn_decl = tcx.hir.fn_decl(mir_node_id)?;
let mir_node_id = infcx.tcx.hir.as_local_node_id(mir_def_id)?;
let fn_decl = infcx.tcx.hir.fn_decl(mir_node_id)?;
let argument_hir_ty: &hir::Ty = &fn_decl.inputs[argument_index];
match argument_hir_ty.node {
// This indicates a variable with no type annotation, like
// `|x|`... in that case, we can't highlight the type but
// must highlight the variable.
hir::TyKind::Infer => None,
hir::TyKind::Infer => self.give_name_if_we_cannot_match_hir_ty(
infcx,
argument_ty,
argument_hir_ty,
counter,
diag,
),
_ => self.give_name_if_we_can_match_hir_ty(
tcx,
infcx.tcx,
needle_fr,
argument_ty,
argument_hir_ty,
@ -197,6 +205,40 @@ impl<'tcx> RegionInferenceContext<'tcx> {
}
}
/// Attempts to highlight the specific part of a type in an argument
/// that has no type annotation.
/// For example, we might produce an annotation like this:
///
/// ```
/// | foo(|a, b| b)
/// | - -
/// | | |
/// | | has type `&'1 u32`
/// | has type `&'2 u32`
/// ```
fn give_name_if_we_cannot_match_hir_ty(
&self,
infcx: &InferCtxt<'_, '_, 'tcx>,
argument_ty: Ty<'tcx>,
argument_hir_ty: &hir::Ty,
counter: &mut usize,
diag: &mut DiagnosticBuilder<'_>,
) -> Option<InternedString> {
let mut type_name = infcx.extract_type_name(&argument_ty);
type_name.find("&").map(|index| {
let region_name = self.synthesize_region_name(counter).as_str();
type_name.insert_str(index + 1, &format!("{} ", region_name));
diag.span_label(
argument_hir_ty.span,
format!("has type `{}`", type_name),
);
region_name.as_interned_str()
})
}
/// Attempts to highlight the specific part of a type annotation
/// that contains the anonymous reference we want to give a name
/// to. For example, we might produce an annotation like this:

17
src/test/ui/issue-52533.nll.stderr Normal file
View file

@ -0,0 +1,17 @@
warning: not reporting region error due to nll
--> $DIR/issue-52533.rs:15:16
|
LL | foo(|a, b| b)
| ^
error: unsatisfied lifetime constraints
--> $DIR/issue-52533.rs:15:16
|
LL | foo(|a, b| b)
| - - ^ free region requires that `'1` must outlive `'2`
| | |
| | lifetime `'1` appears in this argument
| lifetime `'2` appears in this argument
error: aborting due to previous error

17
src/test/ui/issue-52533.rs Normal file
View file

@ -0,0 +1,17 @@
// 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.
fn foo(_: impl for<'a> FnOnce(&'a u32, &u32) -> &'a u32) {
}
fn main() {
foo(|a, b| b)
//~^ ERROR lifetime of reference outlives lifetime of borrowed content...
}

20
src/test/ui/issue-52533.stderr Normal file
View file

@ -0,0 +1,20 @@
error[E0312]: lifetime of reference outlives lifetime of borrowed content...
--> $DIR/issue-52533.rs:15:16
|
LL | foo(|a, b| b)
| ^
|
note: ...the reference is valid for the anonymous lifetime #2 defined on the body at 15:9...
--> $DIR/issue-52533.rs:15:9
|
LL | foo(|a, b| b)
| ^^^^^^^^
note: ...but the borrowed content is only valid for the anonymous lifetime #3 defined on the body at 15:9
--> $DIR/issue-52533.rs:15:9
|
LL | foo(|a, b| b)
| ^^^^^^^^
error: aborting due to previous error
For more information about this error, try `rustc --explain E0312`.