Function analyze_source_plan_schema 

pub fn analyze_source_plan_schema(
    routines: &dyn RoutineResolution,
    source: &SourcePlan,
    params: &[SQLParam],
    ctes: &BindingContext<'_>,
    outer: Option<&RowSchema>,
) -> Result<RowSchema, SQLError>

Derive and validate one FROM source’s exact row type without executing it.