Multi-line where clauses fail to parse with low-level error

[michaeljklein]

Aim

Attempted to separate where clause to multiple lines as is commonly found in Rust

Expected Behavior

It to either fail with an informative error or be accepted as equivalent to a single-line where clause, i.e. impl<A, B> Default for Foo<A, B> where A: Default, B: Default

Bug

Compiling the following:

struct Foo<A, B> { }

impl<A, B> Default for Foo<A, B>
where
    A: Default,
    B: Default,
{
    fn default() -> Self { Foo { } }
}

fails with:

error: Unexpected {, expected one of bool, comptime, crate, dep, Field, fn, fmtstr, impl, str, &, (, [, integer type, Ident
   ┌─ /Users/michaelklein/Coding/rust/noir/test_programs/compile_success_empty/name_shadowing_template/binary/src/local_module.nr:19:1
   │
19 │ {
   │ -
   │

To Reproduce

1. nargo compile the test program as main.nr

Project Impact

Nice-to-have

Impact Context

No response

Workaround

None

Workaround Description

No response

Additional Context

No response

Installation Method

None

Nargo Version

No response

NoirJS Version

No response

Would you like to submit a PR for this Issue?

None

Support Needs

No response

[jfecher]

The error here is a result of the ending comma, removing it results in no errors:

struct Foo<A, B> { }

impl<A, B> Default for Foo<A, B>
where
    A: Default,
    B: Default
{
    fn default() -> Self { Foo { } }
}

The where_clause parser in the parser looks like it is missing an .allow_trailing() call.