Parsed OData query options do not currently support structural equality, which makes semantic comparison of $filter, $orderby, $search, and $select/$expand trees difficult for caching and tests. This change adds draft equality support across the core SemanticAst surface used by those parsed query options.

• Public equality surface

  • Added IEquatable<T>, Equals, and GetHashCode to:
    • QueryNode
    • RangeVariable
    • FilterClause
    • OrderByClause
    • SearchClause
    • SelectExpandClause

• Structural comparison implementation

  • Introduced an internal SemanticAstStructuralEqualityComparer to compare bound query trees by structure rather than object identity.
  • Covers:
    • nested QueryNode graphs
    • RangeVariable state
    • SelectItem / expand item trees
    • ODataPath instances
    • nested clause state such as ComputeClause, LevelsClause, and ApplyClause

• Select/expand support

  • Equality for SelectExpandClause now walks selected items and nested options instead of relying on reference equality.
  • This includes expanded navigation/reference/count items and nested clause options carried on them.

• API baseline

  • Recorded the new public members in the PublicAPI.Unshipped.txt baselines for supported target frameworks.

• Regression coverage

  • Added parser-based tests that compare separately parsed but semantically equivalent trees for:
    • $filter
    • $orderby
    • $search
    • $select/$expand
  • Also added non-equivalence cases to verify the comparer distinguishes different semantics.

Example:

var left = new ODataQueryOptionParser(model, type, set,
    new Dictionary<string, string> { ["$filter"] = "MyDog/Color eq 'Brown'" })
    .ParseFilter();

var right = new ODataQueryOptionParser(model, type, set,
    new Dictionary<string, string> { ["$filter"] = "MyDog/Color eq 'Brown'" })
    .ParseFilter();

bool equal = left.Equals(right); // true