Extend E0623 for named conflicts

[gaurikholkar-zz]

Adding changes for rl::Region::EarlyBound and rl::Region::LateBound for references.
Still looking for good examples

cc @nikomatsakis @estebank @GuillaumeGomez @arielb1

[gaurikholkar-zz]

Here's the code I pushed into a local branch.
I need help with examples for both the cases.

[gaurikholkar-zz]

Status:The check for if debruijn_index.depth == 1 && self.infcx.tcx.hir.local_def_id(id) == def_id fails for LateBound

fn foo<'a,'b>(x: &mut Vec<&'a u8>, y: &'b u8) {
    x.push(y);
}

Logs are

DEBUG:rustc::infer::error_reporting: report_region_errors: error = ConcreteFailure(Reborrow(src/test/ui/lifetime-errors/ex3-both-anon-regions.rs:12:12: 12:13), ReFree(DefId { krate: CrateNum(0), node: DefIndex(3) => ex3_both_anon_regions/8cd878b::foo[0] }, BrNamed(CrateNum(0):DefIndex(2147483657), 'a(86))), ReFree(DefId { krate: CrateNum(0), node: DefIndex(3) => ex3_both_anon_regions/8cd878b::foo[0] }, BrNamed(CrateNum(0):DefIndex(2147483658), 'b(88))))
DEBUG:rustc::infer::error_reporting::named_anon_conflict: try_report_named_anon_conflict
DEBUG:rustc::infer::error_reporting::named_anon_conflict: 1.1
DEBUG:rustc::infer::error_reporting::util: arg=Arg { pat: pat(16: y), id: NodeId(15) }
DEBUG:rustc::infer::error_reporting::anon_anon_conflict: try_report_anon_anon_conflict
DEBUG:rustc::infer::error_reporting::anon_anon_conflict: LateBound depth = 1 self.infcx.tcx.hir.local_def_id(id) =DefId { krate: CrateNum(0), node: DefIndex(2147483658) => ex3_both_anon_regions/8cd878b::foo[0]::'b[0] }
                        def_id=DefId { krate: CrateNum(0), node: DefIndex(2147483658) => ex3_both_anon_regions/8cd878b::foo[0]::'b[0] }
DEBUG:rustc::infer::error_reporting::anon_anon_conflict: LateBound depth = 1 self.infcx.tcx.hir.local_def_id(id) =DefId { krate: CrateNum(0), node: DefIndex(2147483658) => ex3_both_anon_regions/8cd878b::foo[0]::'b[0] }
                        def_id=DefId { krate: CrateNum(0), node: DefIndex(2147483657) => ex3_both_anon_regions/8cd878b::foo[0]::'a[0] }

[gaurikholkar-zz]

@nikomatsakis
for EarlyBound

fn foo<'a,'b>(x: &mut Vec<&'a u8>, y: &'b u8) where &'a (): Sized, &'b u32: Sized {
        x.push(y);
}

I've confirmed with @arielb1 that this is the correct example for the case but it doesn't seem to trigger the EarlyBound case in the code.

[GuillaumeGomez]

Could you add in which case this code will improve the current rustc output please? (Put a code with the current output and then the improved one.) It'll help us to understand what you want to do.

[gaurikholkar-zz]

@GuillaumeGomez here is the example

fn foo<'a, 'b>(x: &mut Vec<&'a u8>, y: &'b u8) {
    x.push(y);
}

Current output

error[E0312]: lifetime of reference outlives lifetime of borrowed content...
 --> src/main.rs:2:12
  |
2 |     x.push(y);
  |            ^
  |
note: ...the reference is valid for the lifetime 'a as defined on the function body at 1:1...
 --> src/main.rs:1:1
  |
1 | / fn foo<'a, 'b>(x: &mut Vec<&'a u8>, y: &'b u8) {
2 | |     x.push(y);
3 | | }
  | |_^
note: ...but the borrowed content is only valid for the lifetime 'b as defined on the function body at 1:1
 --> src/main.rs:1:1
  |
1 | / fn foo<'a, 'b>(x: &mut Vec<&'a u8>, y: &'b u8) {
2 | |     x.push(y);
3 | | }
  | |_^

New output

error[E0623]: lifetime mismatch
  --> $DIR/ex3-both-anon-regions.rs:12:12
   |
11 | fn foo<'a, 'b>(x: &mut Vec<&'a u8>, y: &'b u8) {
   |                            ------      ------ these two types are declared with different lifetimes...
12 |     x.push(y);
   |            ^ ...but data from `y` flows into `x` here
error: aborting due to previous error

[gaurikholkar-zz]

In the process of doing it for structs now
#44549

[gaurikholkar-zz]

• Structs
• Function and Trait Items
• Free fns, trait definitions and impls
  cc @nikomatsakis you can add the other cases

[estebank]

@gaurikholkar, are there outstanding tasks for this issue?

[gaurikholkar-zz]

Nope. @estebank updated the title.

[BGR360]

Sooo, can this be closed?

[GuillaumeGomez]

I guess so.