Handle [Obsolete]

docs/DocDeprecation.md

@@ -0,0 +1,22 @@
+# Summary.DocDeprecation
+```cs
+public record DocDeprecation
+```
+
+Contains deprecation information (e.g. the warning message).
+
+## Properties
+### Message
+```cs
+public string? Message { get; init; }
+```
+
+The deprecation warning message.
+
+### Error
+```cs
+public bool Error { get; init; }
+```
+
+Whether the usage should be treated as an error instead of a warning.
+

docs/DocMember.md

@@ -49,6 +49,21 @@ public required DocType? DeclaringType { get; init; }
 
 The type that this member is declared in (works for nested types as well).
 
+### Deprecated
+```cs
+[MemberNotNullWhen(true, nameof(Deprecation))]
+public bool Deprecated { get; }
+```
+
+Whether the member is deprecated (e.g. marked with `[Obsolete]`).
+
+### Deprecation
+```cs
+public DocDeprecation? Deprecation { get; init; }
+```
+
+The member deprecation information.
+
 ## Methods
 ### MatchesCref(string)
 ```cs

docs/Sample{T0,T1}.Child.md

@@ -1,5 +1,9 @@
-# Summary.Samples.Sample.Child
+# ~~Summary.Samples.Sample.Child~~
+> [!WARNING]
+> The type is deprecated.
+
 ```cs
+[Obsolete(error: true, message: "The type is deprecated.")]
 public class Child
 ```
 

docs/Sample{T0,T1}.md

@@ -52,8 +52,12 @@ public int Field
 
 A field of the child class.
 
-### Field1
+### ~~Field1~~
+> [!WARNING]
+> The field is deprecated.
+
 ```cs
+[Obsolete("The field is deprecated.")]
 public int Field1
 ```
 

src/Core/DocDeprecation.cs

@@ -0,0 +1,17 @@
+namespace Summary;
+
+/// <summary>
+///     Contains deprecation information (e.g. the warning message).
+/// </summary>
+public record DocDeprecation
+{
+    /// <summary>
+    ///     The deprecation warning message.
+    /// </summary>
+    public string? Message { get; init; }
+
+    /// <summary>
+    ///     Whether the usage should be treated as an error instead of a warning.
+    /// </summary>
+    public bool Error { get; init; }
+}

src/Core/DocMember.cs

@@ -1,4 +1,6 @@
-namespace Summary;
+using System.Diagnostics.CodeAnalysis;
+
+namespace Summary;
 
 /// <summary>
 ///     A member of the generated document (e.g. type, field, property, method, etc.).
@@ -36,6 +38,17 @@ public abstract record DocMember
     /// </summary>
     public required DocType? DeclaringType { get; init; }
 
+    /// <summary>
+    ///     Whether the member is deprecated (e.g. marked with <c>[Obsolete]</c>).
+    /// </summary>
+    [MemberNotNullWhen(true, nameof(Deprecation))]
+    public bool Deprecated => Deprecation is not null;
+
+    /// <summary>
+    ///     The member deprecation information.
+    /// </summary>
+    public DocDeprecation? Deprecation { get; init; }
+
     /// <summary>
     ///     Whether this member matches the specified `cref` reference.
     /// </summary>

src/Core/Extensions/StringExtensions.cs

@@ -16,6 +16,13 @@ public static string Space(this string self) =>
     public static string Surround(this string self, string left, string right) =>
         self.Map(x => $"{left}{x}{right}");
 
+    /// <summary>
+    ///     Surrounds the specified string with the given prefix and suffix strings
+    ///     if the specified condition is satisfied. If the string is empty, returns the string as is.
+    /// </summary>
+    public static string Surround(this string self, string left, string right, bool when) =>
+        when ? self.Surround(left, right) : self;
+
     private static string Map(this string self, Func<string, string> map) =>
         self is "" ? self : map(self);
 

src/Core/Samples/Sample.cs

@@ -29,6 +29,7 @@ public class Sample<T0, T1>
     /// <summary>
     ///     A child of the <see cref="Sample{T0,T1}"/> class.
     /// </summary>
+    [Obsolete(error: true, message: "The type is deprecated.")]
     public class Child
     {
         /// <summary>
@@ -45,6 +46,7 @@ public class Child
     /// <summary>
     ///     A sample field.
     /// </summary>
+    [Obsolete("The field is deprecated.")]
     public int Field1;
 
     /// <summary>