[ScottishTapWater]

Summary

• Infer quantity dimensions through ordinary var local initialisers and copied locals, so arithmetic can be split across statements.
• Separate expression analysis from arithmetic candidate discovery, with symbol-based local caching and cycle detection scoped to each analysis.
• Preserve bound types and declaration-based inference; do not infer from later assignments or unresolved explicit type names.
• Add tests for dependency chains, scalar factors, reused locals, scope identity, incomplete/cyclic code and incremental edits/removal.
• Keep each Roslyn test class in one file and update the README scope statement.

var squared = current * current;
var heating = squared * resistance;
var energy = heating * time;

Verification

• Tests written first: 12 new cases failed before implementation.
• 410 tests pass: 306 core, 103 Roslyn and 1 packaged-consumer integration test.
• C# production and test reviews completed, followed by a second pass after coverage fixes and a final review after test consolidation.
• Explicit checks for test ownership and overgrown class responsibilities found no remaining issues.
• Formatting check passes with the existing RS1041 diagnostic excluded; diff whitespace check passes.

Roots, powers, dimensionless results and unresolved explicit type-name inference remain outside this slice.