P3: assets' posted and scheduled depreciation, their bases, and the K-1 on the tax basis (defect 13, D-41)

Book value is cost less what the books posted; the schedule's figure is
apart. An asset's acquired date comes from its entry. Contributed
property keeps its section 723 carryover basis apart from its depreciable
basis (the lower of value and adjusted basis), with its 704(c) built-in
gain and method. The K-1 worksheet reports tax-basis capital (Form 1065
Item L) beside the book figures, leaving open what only the CPA knows.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01T3gXMVt7XJPi6ens1or9Dj

crates/ledger-core/src/error.rs

@@ -166,11 +166,35 @@ pub enum LedgerError {
         why: String,
     },
 
-    /// An asset's tax basis record doesn't fit its rule (see
-    /// `Ledger::set_asset_tax_basis`).
+    /// An asset's basis record doesn't fit its rule (see
+    /// `Ledger::set_asset_basis`).
     #[error("bad tax basis: {0}")]
     InvalidTaxBasis(String),
 
+    /// An asset can't be in service before the company acquired it: its
+    /// in-service date is before its acquisition entry's date.
+    #[error(
+        "asset {asset} can't be in service on {in_service}, before it was acquired on {acquired} (its acquisition entry's date): correct the in-service date, or the entry"
+    )]
+    InServiceBeforeAcquisition {
+        /// The asset.
+        asset: u64,
+        /// The in-service date given.
+        in_service: String,
+        /// The acquisition entry's date.
+        acquired: String,
+    },
+
+    /// A depreciation run that doesn't fit its asset or entry (see
+    /// `Ledger::check_depreciation_run`).
+    #[error("bad depreciation run for asset {asset}: {why}")]
+    InvalidDepreciationRun {
+        /// The asset.
+        asset: u64,
+        /// Why not.
+        why: String,
+    },
+
     /// No party has this id.
     #[error("unknown party {0}")]
     UnknownParty(u64),
@@ -411,17 +435,24 @@ pub enum LedgerError {
     #[error("disposal proceeds must not be negative, got {0}")]
     NegativeProceeds(Decimal),
 
-    /// Disposal date must not precede the purchase date.
-    #[error("disposal date {0} is before the purchase date")]
-    DisposalBeforePurchase(String),
+    /// A disposal can't come before the company acquired the asset (its
+    /// acquisition entry's date, or its in-service date when none is
+    /// linked).
+    #[error("disposal date {date} is before the asset was acquired ({acquired})")]
+    DisposalBeforeAcquisition {
+        /// The disposal date given.
+        date: String,
+        /// The acquired date.
+        acquired: String,
+    },
 
     /// The three asset account links must be three distinct accounts.
     #[error("asset account links must be distinct; account id {0} is linked twice")]
     DuplicateAssetAccount(u64),
 
-    /// purchase_date + useful life overflows the date range: a new asset's
-    /// last day of depreciation is 9999-12-31 at the latest.
-    #[error("purchase date plus useful life overflows the calendar")]
+    /// in-service date + useful life overflows the date range: a new
+    /// asset's last day of depreciation is 9999-12-31 at the latest.
+    #[error("in-service date plus useful life overflows the calendar")]
     AssetDateOverflow,
 
     /// A depreciation run for a month that can't be run: not a month, or