From 30555f17766d0d428866c165c616065573b2409f Mon Sep 17 00:00:00 2001
From: Gerrit Birkeland <gerrit@gerritbirkeland.com>
Date: Sat, 29 Oct 2022 15:01:02 -0600
Subject: [PATCH] Fix comment discovery for `@inheritDoc`

Resolves #2087
---
 CHANGELOG.md                                  |  4 ++++
 src/lib/converter/plugins/InheritDocPlugin.ts | 18 ++++++++++++++++++
 src/test/converter2/issues/gh2087.ts          |  9 +++++++++
 src/test/issueTests.ts                        |  8 ++++++++
 4 files changed, 39 insertions(+)
 create mode 100644 src/test/converter2/issues/gh2087.ts

diff --git a/CHANGELOG.md b/CHANGELOG.md
index f50b4a0ff..e2c6ecad4 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,9 @@
 # Unreleased
 
+### Bug Fixes
+
+-   Fixed comment discovery for `@inheritDoc` if inheriting from a function type alias, #2087.
+
 ## v0.23.19 (2022-10-28)
 
 ### Bug Fixes
diff --git a/src/lib/converter/plugins/InheritDocPlugin.ts b/src/lib/converter/plugins/InheritDocPlugin.ts
index 268220f79..4ba1f0317 100644
--- a/src/lib/converter/plugins/InheritDocPlugin.ts
+++ b/src/lib/converter/plugins/InheritDocPlugin.ts
@@ -2,6 +2,7 @@ import {
     Comment,
     DeclarationReflection,
     ReflectionKind,
+    ReflectionType,
     SignatureReflection,
 } from "../../models";
 import { Component, ConverterComponent } from "../components";
@@ -105,6 +106,23 @@ export class InheritDocPlugin extends ConverterComponent {
     private copyComment(source: Reflection, target: Reflection) {
         if (!target.comment) return;
 
+        if (
+            !source.comment &&
+            source instanceof DeclarationReflection &&
+            source.signatures
+        ) {
+            source = source.signatures[0];
+        }
+
+        if (
+            !source.comment &&
+            source instanceof DeclarationReflection &&
+            source.type instanceof ReflectionType &&
+            source.type.declaration.signatures
+        ) {
+            source = source.type.declaration.signatures[0];
+        }
+
         if (!source.comment) {
             this.application.logger.warn(
                 `${target.getFullName()} tried to copy a comment from ${source.getFullName()} with @inheritDoc, but the source has no associated comment.`
diff --git a/src/test/converter2/issues/gh2087.ts b/src/test/converter2/issues/gh2087.ts
new file mode 100644
index 000000000..7fe250cc0
--- /dev/null
+++ b/src/test/converter2/issues/gh2087.ts
@@ -0,0 +1,9 @@
+/** Foo type comment */
+export type Foo = () => number;
+
+export class Bar {
+    /**
+     * {@inheritDoc Foo:type}
+     */
+    x = 1;
+}
diff --git a/src/test/issueTests.ts b/src/test/issueTests.ts
index 1587e93f7..c35c209e0 100644
--- a/src/test/issueTests.ts
+++ b/src/test/issueTests.ts
@@ -817,4 +817,12 @@ export const issueTests: {
         const sig = cap.signatures![0];
         equal(sig.type?.toString(), "Capitalize<T>");
     },
+
+    gh2087(project) {
+        const x = query(project, "Bar.x");
+        equal(
+            Comment.combineDisplayParts(x.comment?.summary),
+            "Foo type comment"
+        );
+    },
 };