NatSpec: Disallow @return tag on events.

Changelog.md

@@ -5,6 +5,7 @@ Language Features:
 Compiler Features:
 
 Bugfixes:
+* NatSpec: Disallow `@return` tag in event documentation.
 
 
 ### 0.8.35 (2026-04-29)

libsolidity/analysis/DocStringTagParser.cpp

@@ -285,7 +285,7 @@ void DocStringTagParser::handleCallable(
 	StructurallyDocumentedAnnotation& _annotation
 )
 {
-	static std::set<std::string> const validEventTags = std::set<std::string>{"dev", "notice", "return", "param"};
+	static std::set<std::string> const validEventTags = std::set<std::string>{"dev", "notice", "param"};
 	static std::set<std::string> const validErrorTags = std::set<std::string>{"dev", "notice", "param"};
 	static std::set<std::string> const validModifierTags = std::set<std::string>{"dev", "notice", "param", "inheritdoc"};
 	static std::set<std::string> const validTags = std::set<std::string>{"dev", "notice", "return", "param", "inheritdoc"};

test/libsolidity/natspecJSON/invalid/docstring_event_return.sol

@@ -0,0 +1,6 @@
+contract C {
+	/// @return foo
+	event E(uint x);
+}
+// ----
+// DocstringParsingError 6546: (14-29): Documentation tag @return not valid for events.

test/libsolidity/natspecJSON/invalid/docstring_event_return_inheritance.sol

@@ -0,0 +1,10 @@
+interface I {
+	event E(uint x);
+}
+contract C is I {
+	/// @return bar
+	event E(uint x);
+}
+// ----
+// DocstringParsingError 6546: (53-68): Documentation tag @return not valid for events.
+// DeclarationError 5883: (70-86): Event with same name and parameter types defined twice.