[jogibear9988]

Lifted conversions whose method takes a ref parameter can emit invalid IL or mishandle null propagation. Classify the formal underlying type, emit the nullable operand as a value and pass a typed underlying temporary to the method. Preserve nullable results, checked null unwrapping and copy semantics; leave nonlifted operand storage unchanged.

Validation

The focused regression reproduces a failure or crash on master a0950432 and passes with this change. Release solution build passes with zero warnings/errors. Both Standard and LightExpression native suites run; ref-conversion-method regressions target the System.Linq.Expressions input API.

Runtime	TestX passed	Legacy passed
.NET 10	359	1,756
.NET 8	359	1,755
.NET Framework 4.7.2	340	1,639

Measurements

Compare master a0950432 with this commit 48b0db7e. Windows ARM64, Release; .NET 8.0.28 and 10.0.9. Compilation uses prebuilt trees; invocation uses precompiled delegates and excludes expression construction/compilation. Standard and LightExpression are measured separately.

Two fresh process rounds reverse version-loading order, pin execution to one logical CPU, disable tiered compilation, warm both versions, and alternate measurement order. Values below are medians across 14 samples per side (seven per round; 30 ms calibration target).

Measured compilation and invocation allocations match master on every control. Control delegate IL matches master.

Identical-master control runs also varied: compilation -15.2% to +23.4%, invocation -21.5% to +8.9%. Timings below are observations, not a speedup or universal performance-neutrality claim. Cases that fail or produce invalid IL on master have no meaningful before/after invocation ratio; the table uses executable controls that return the expected result in both versions. Framework correctness is tested above; its performance is not measured here.

All table pairs are master → this change. B/op is allocated bytes per operation.

.NET / API	Control	Compile ns/op	Compile B/op	Invoke ns/op	Invoke B/op
10 / Light	add_control	2,487 → 2,474	872 → 872	1.92 → 1.93	0 → 0
10 / Light	nullable_conversion	5,663 → 5,465	1648 → 1648	2.02 → 2.03	0 → 0
10 / Light	numeric_conversion	2,394 → 2,326	872 → 872	1.95 → 1.93	0 → 0
10 / Standard	add_control	3,022 → 2,958	872 → 872	1.90 → 1.91	0 → 0
10 / Standard	method_conversion	3,119 → 3,155	928 → 928	1.99 → 1.95	0 → 0
10 / Standard	method_nullable_conversion	5,672 → 5,807	1704 → 1704	1.93 → 1.96	0 → 0
10 / Standard	nullable_conversion	5,769 → 5,883	1648 → 1648	1.96 → 1.93	0 → 0
10 / Standard	numeric_conversion	3,052 → 3,064	872 → 872	1.96 → 1.95	0 → 0
8 / Light	add_control	992 → 944	872 → 872	1.92 → 1.90	0 → 0
8 / Light	nullable_conversion	2,129 → 2,272	1648 → 1648	2.22 → 2.08	0 → 0
8 / Light	numeric_conversion	887 → 919	872 → 872	2.28 → 2.30	0 → 0
8 / Standard	add_control	1,019 → 1,068	872 → 872	2.00 → 2.02	0 → 0
8 / Standard	method_conversion	1,078 → 1,076	928 → 928	2.26 → 2.28	0 → 0
8 / Standard	method_nullable_conversion	2,289 → 2,176	1704 → 1704	2.23 → 2.24	0 → 0
8 / Standard	nullable_conversion	2,918 → 2,858	1648 → 1648	2.59 → 2.67	0 → 0
8 / Standard	numeric_conversion	1,068 → 1,066	872 → 872	2.32 → 2.31	0 → 0