Diagnostics

All SqlBound diagnostics use the SQLB prefix. IDs below 100 are usage diagnostics reported by the source generator — they validate how the attributes are used and never need a database. IDs from 101 are verification diagnostics reported by the analyzer — they compare a method's declared signature against the committed .sqlbound/ snapshot for its SQL (see ADR 0001/0003).

Severities are defaults; consumers can retune any of them via .editorconfig (dotnet_diagnostic.SQLB101.severity = error).

Usage (SqlBound.Usage, generator)

ID	Severity	Meaning
SQLB001	Error	[SqlQuery]/[SqlExecute] method must be a partial definition without a body
SQLB002	Error	Method must be static
SQLB003	Error	Method must take a DbConnection (or derived) first parameter
SQLB004	Error	Unsupported [SqlQuery] return type
SQLB005	Error	Row type has no supported mapping (constructor or settable properties)
SQLB006	Error	Query parameter type is not supported
SQLB007	Error	Command text must not be empty
SQLB008	Error	Method must not be generic or nested in a generic type
SQLB009	Error	[SqlExecute] method must return Task or Task<int>
SQLB010	Error	A method cannot carry both [SqlQuery] and [SqlExecute]

Verification (SqlBound.Verification, analyzer)

Reported only once the project has opted in by committing .sqlbound/ snapshots (ADR 0003); a project with no snapshots hears nothing.

ID	Severity	Meaning
SQLB101	Warning	Query has no snapshot — run the prepare step
SQLB102	Warning	Snapshot is unreadable or no longer matches the command text — re-run prepare
SQLB103	Error	Statement produces no result set, but the method expects one
SQLB104	Error	Result set has no column with a declared name
SQLB105	Error	Column CLR type differs from the declaration
SQLB106	Error	Database column is nullable but declared non-nullable (the safe converse is silent)
SQLB107	Info	Result set returns columns the method never reads
SQLB108	Error	Statement uses a parameter the method does not declare
SQLB109	Warning	Method declares a scalar parameter the statement never uses
SQLB110	Error	Parameter CLR type differs from the declaration
SQLB111	Warning	[SqlExecute] statement returns a result set it discards

Two comparison rules worth knowing:

• Columns match by case-insensitive name, not position — generated code binds with GetOrdinal(name), so reordering a SELECT list is never a mismatch. Scalar-shaped methods verify the first column instead.
• Types compare as mapped CLR types, not SQL type names — SQL Server's suggested parameter types are inferences (a comparison against decimal(18,2) suggests decimal(38,19)), so raw SQL type comparison would false-positive.
• SQLB110 needs a provider-reported parameter type to fire. SQLite and MySQL have no static parameter typing (see introspection.md), so a parameter sourced from either never triggers SQLB110 — its C# type is trusted from the method's own declared signature rather than verified.