Index: clang-tools-extra/clang-tidy/modernize/RedundantVoidArgCheck.cpp
===================================================================
--- clang-tools-extra/clang-tidy/modernize/RedundantVoidArgCheck.cpp
+++ clang-tools-extra/clang-tidy/modernize/RedundantVoidArgCheck.cpp
@@ -97,9 +97,12 @@
 
 void RedundantVoidArgCheck::processFunctionDecl(
     const MatchFinder::MatchResult &Result, const FunctionDecl *Function) {
+  const auto *Method = dyn_cast<CXXMethodDecl>(Function);
+  SourceLocation Start = Method && Method->getParent()->isLambda()
+                             ? Method->getBeginLoc()
+                             : Function->getLocation();
+  SourceLocation End = Function->getEndLoc();
   if (Function->isThisDeclarationADefinition()) {
-    SourceLocation Start = Function->getBeginLoc();
-    SourceLocation End = Function->getEndLoc();
     if (const Stmt *Body = Function->getBody()) {
       End = Body->getBeginLoc();
       if (End.isMacroID() &&
@@ -110,7 +113,7 @@
     removeVoidArgumentTokens(Result, SourceRange(Start, End),
                              "function definition");
   } else {
-    removeVoidArgumentTokens(Result, Function->getSourceRange(),
+    removeVoidArgumentTokens(Result, SourceRange(Start, End),
                              "function declaration");
   }
 }
Index: clang-tools-extra/test/clang-tidy/checkers/modernize-redundant-void-arg.cpp
===================================================================
--- clang-tools-extra/test/clang-tidy/checkers/modernize-redundant-void-arg.cpp
+++ clang-tools-extra/test/clang-tidy/checkers/modernize-redundant-void-arg.cpp
@@ -556,3 +556,9 @@
   S_3<int>();
   g_3<int>();
 }
+
+#define return_t(T) T
+return_t(void) func(void);
+// CHECK-MESSAGES: :[[@LINE-1]]:21: warning: redundant void argument list in function declaration
+// CHECK-FIXES: return_t(void) func();
+#undef return_t