[electricessence]

command.SingleResult().Map<T>(): the opt-out reads as behavior, then shape.

// Before: only after Map
var rows = await command.Map<Post>().SingleResult().ToListAsync(ct);

// Now, also before Map (identical meaning)
var rows = await command.SingleResult().Map<Post>().ToListAsync(ct);

What

• SingleResult() is now an extension on IExecuteReader (expressive commands) and on IDbCommand (raw commands), usable before Map. x.SingleResult().Map<T>() is exactly x.Map<T>().SingleResult(), for every terminal, sync and async. The after-Map form still works.
• SingleResult() is the one explicit opt-out of the library's read-through: the query reads the first result set and stops, so a failure in a later statement is not seen. That behavior and every default are unchanged. It is not on IDataReader or DataTable, which are single-result already.
• New public surface: the two extension methods, SingleResult(this IExecuteReader) and SingleResult(this IDbCommand). No new public type: they return an internal wrapper that carries the flag. Map unwraps it and runs against the ORIGINAL command with the query's existing single-result flag, so nothing on the Map path executes through the wrapper, and the caller's command is never changed.
• A caller who uses the returned view directly as a command gets one that forwards every member and adds CommandBehavior.SingleResult to each reader it opens. Disposing that view disposes the command (documented).

Notes for review

• The before-Map form allocates one small wrapper object per query; the after-Map form allocates nothing.
• A type of your own that implements both IExecuteReader and IDbCommand gets CS0121 on SingleResult(), as it already does on Map.

Docs

• The SingleResult remarks and the multiple-result-sets text in mapping.md now show the before-Map form first and mention that the after-Map form works; whats-new-11.md has an entry.

Tests

• 154 cases: both forms compared on every terminal (ToList, ToArray, ToImmutableArray, FirstOrDefault, SingleOrDefault, ToDictionary, ToHashSet, Read, Skip, Take, Skip+Take, Take+FirstOrDefault), sync and async, for an expressive command, a DbCommand and a plain IDbCommand; a later-set failure is thrown without the opt-out and not with it (text and stored-procedure commands); the five Map overloads bind and Skip/Take keep the flag; the after-Map form alone and combined; the command is not mutated; null throws; both tokens cancel; compile-only binding for ExpressiveSqlCommand from both SQL Server packages, ExpressiveCommand, ExpressiveDbCommand, SqlCommand, DbCommand and IDbCommand.

Checks

• Release and Debug builds: 0 warnings, 0 errors. Tests: 9831 of 9831 pass in both. Samples: 103 of 103 checks pass. Style and analyzers: 0 findings. DocFX: 0 warnings.

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