diff --git a/clang-tools-extra/clang-tidy/misc/DefinitionsInHeadersCheck.cpp b/clang-tools-extra/clang-tidy/misc/DefinitionsInHeadersCheck.cpp
--- a/clang-tools-extra/clang-tidy/misc/DefinitionsInHeadersCheck.cpp
+++ b/clang-tools-extra/clang-tidy/misc/DefinitionsInHeadersCheck.cpp
@@ -132,8 +132,7 @@
         << IsFullSpec << FD;
     diag(FD->getLocation(), /*FixDescription=*/"make as 'inline'",
          DiagnosticIDs::Note)
-        << FixItHint::CreateInsertion(FD->getReturnTypeSourceRange().getBegin(),
-                                      "inline ");
+        << FixItHint::CreateInsertion(FD->getInnerLocStart(), "inline ");
   } else if (const auto *VD = dyn_cast<VarDecl>(ND)) {
     // Static data members of a class template are allowed.
     if (VD->getDeclContext()->isDependentContext() && VD->isStaticDataMember())
diff --git a/clang-tools-extra/test/clang-tidy/misc-definitions-in-headers.hpp b/clang-tools-extra/test/clang-tidy/misc-definitions-in-headers.hpp
--- a/clang-tools-extra/test/clang-tidy/misc-definitions-in-headers.hpp
+++ b/clang-tools-extra/test/clang-tidy/misc-definitions-in-headers.hpp
@@ -180,3 +180,15 @@
 constexpr int k = 1; // OK: constexpr variable has internal linkage.
 
 constexpr int f10() { return 0; } // OK: constexpr function definition.
+
+const int f11() { return 0; }
+// CHECK-MESSAGES: :[[@LINE-1]]:11: warning: function 'f11' defined in a header file;
+// CHECK-FIXES: inline const int f11() { return 0; }
+
+template <typename T>
+const T f12();
+
+template <>
+const int f12() { return 0; }
+// CHECK-MESSAGES: :[[@LINE-1]]:11: warning: full function template specialization 'f12<int>' defined in a header file;
+// CHECK-FIXES: inline const int f12() { return 0; }