Fixes issue of trait implementation not beeing used.

When constraint is used in generic functions the trait name does not
contain any prefixes this was causing
get_methods_for_type_and_trait_name to return no methods to be used.

Closes FuelLabs#3326

sway-core/src/semantic_analysis/namespace/trait_map.rs

@@ -679,7 +679,10 @@ impl TraitMap {
                 suffix: e.key.name.suffix.name.clone(),
                 is_absolute: e.key.name.is_absolute,
             };
-            if &map_trait_name == trait_name
+            let are_same_name_traits = (trait_name.prefixes.is_empty()
+                && map_trait_name.suffix == trait_name.suffix)
+                || &map_trait_name == trait_name;
+            if are_same_name_traits
                 && are_equal_minus_dynamic_types(type_engine, type_id, e.key.type_id)
             {
                 let mut trait_methods = e.value.values().cloned().into_iter().collect::<Vec<_>>();

test/src/e2e_vm_tests/test_programs/should_pass/stdlib/eq_custom_type/Forc.lock

@@ -0,0 +1,13 @@
+[[package]]
+name = 'core'
+source = 'path+from-root-33945E385D757681'
+
+[[package]]
+name = 'eq_custom_type'
+source = 'member'
+dependencies = ['std']
+
+[[package]]
+name = 'std'
+source = 'path+from-root-33945E385D757681'
+dependencies = ['core']

test/src/e2e_vm_tests/test_programs/should_pass/stdlib/eq_custom_type/Forc.toml

@@ -0,0 +1,8 @@
+[project]
+authors = ["Fuel Labs <contact@fuel.sh>"]
+entry = "main.sw"
+license = "Apache-2.0"
+name = "eq_custom_type"
+
+[dependencies]
+std = { path = "../../../../../../../sway-lib-std" }

test/src/e2e_vm_tests/test_programs/should_pass/stdlib/eq_custom_type/json_abi_oracle.json

@@ -0,0 +1,22 @@
+{
+  "functions": [
+    {
+      "inputs": [],
+      "name": "main",
+      "output": {
+        "name": "",
+        "type": 0,
+        "typeArguments": null
+      }
+    }
+  ],
+  "loggedTypes": [],
+  "types": [
+    {
+      "components": null,
+      "type": "bool",
+      "typeId": 0,
+      "typeParameters": null
+    }
+  ]
+}

test/src/e2e_vm_tests/test_programs/should_pass/stdlib/eq_custom_type/src/main.sw

@@ -0,0 +1,30 @@
+script;
+
+use core::ops::*;
+
+enum Error {
+    BoolError: bool,      
+    U8Error: u8,      
+}
+
+impl Eq for Error {
+    fn eq(self, other: Self) -> bool {
+        match (self, other) {
+            (Error::BoolError(val1), Error::BoolError(val2)) => val2 == val1,
+            (Error::U8Error(val1), Error::U8Error(val2)) => val2 == val1,
+            _ => false,
+        }
+    }
+}
+
+fn test_none_ok_or<T, E>(_val: T, default: E) where E: Eq {
+    match Option::None::<T>().ok_or(default) {
+        Result::Ok(_) => revert(0),
+        Result::Err(e) => assert(default == e),
+    }
+}
+
+fn main() -> bool {
+    test_none_ok_or(true, Error::BoolError(true));
+    return true;
+}

test/src/e2e_vm_tests/test_programs/should_pass/stdlib/eq_custom_type/test.toml

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