Adds test that proves unexpected error no longer occcurs. (#5910)

## Description

The issue reported in #4689 is already fixed.
This PR only adds a test to prove it works as expected.

Closes #4689.

## Checklist

- [x] I have linked to any relevant issues.
- [x] I have commented my code, particularly in hard-to-understand
areas.
- [ ] I have updated the documentation where relevant (API docs, the
reference, and the Sway book).
- [ ] If my change requires substantial documentation changes, I have
[requested support from the DevRel
team](https://github.com/FuelLabs/devrel-requests/issues/new/choose)
- [x] I have added tests that prove my fix is effective or that my
feature works.
- [x] I have added (or requested a maintainer to add) the necessary
`Breaking*` or `New Feature` labels where relevant.
- [x] I have done my best to ensure that my PR adheres to [the Fuel Labs
Code Review
Standards](https://github.com/FuelLabs/rfcs/blob/master/text/code-standards/external-contributors.md).
- [x] I have requested a review from the relevant team or maintainers.

Co-authored-by: Joshua Batty <joshpbatty@gmail.com>

test/src/e2e_vm_tests/test_programs/should_pass/language/generic_struct_instantiation/Forc.lock

@@ -0,0 +1,3 @@
+[[package]]
+name = "generic_struct_instantiation"
+source = "member"

test/src/e2e_vm_tests/test_programs/should_pass/language/generic_struct_instantiation/Forc.toml

@@ -0,0 +1,6 @@
+[project]
+authors = ["Fuel Labs <contact@fuel.sh>"]
+license = "Apache-2.0"
+name = "generic_struct_instantiation"
+entry = "main.sw"
+implicit-std = false

test/src/e2e_vm_tests/test_programs/should_pass/language/generic_struct_instantiation/src/main.sw

@@ -0,0 +1,22 @@
+script;
+
+trait Trait {
+  fn method();
+}
+
+#[allow(dead_code)]
+struct Struct<T> where T: Trait {
+
+}
+
+impl Trait for u64 {
+  #[allow(dead_code)]
+  fn method() {}
+}
+
+#[allow(dead_code)]
+const C: Struct<u64> = Struct{};
+
+fn main() -> u64 {
+  1
+}

test/src/e2e_vm_tests/test_programs/should_pass/language/generic_struct_instantiation/test.toml

@@ -0,0 +1,3 @@
+category = "run"
+expected_result = { action = "return", value = 1 }
+validate_abi = false