diff --git a/kdevplatform/language/duchain/stringhelpers.h b/kdevplatform/language/duchain/stringhelpers.h
--- a/kdevplatform/language/duchain/stringhelpers.h
+++ b/kdevplatform/language/duchain/stringhelpers.h
@@ -97,6 +97,11 @@
  */
 int KDEVPLATFORMLANGUAGE_EXPORT strip( const QByteArray& str, QByteArray& from );
 
+/**
+ * Removes all whitespace from the string
+ */
+QString KDEVPLATFORMLANGUAGE_EXPORT removeWhitespace( const QString& str );
+
 /**
  * Can be used to iterate through different kinds of parameters, for example template-parameters
  */
diff --git a/kdevplatform/language/duchain/stringhelpers.cpp b/kdevplatform/language/duchain/stringhelpers.cpp
--- a/kdevplatform/language/duchain/stringhelpers.cpp
+++ b/kdevplatform/language/duchain/stringhelpers.cpp
@@ -508,6 +508,12 @@
   return formatComment_impl<QString>(comment);
 }
 
+QString removeWhitespace(const QString& str)
+{
+  return str.simplified().remove(QLatin1Char(' '));
+}
+
+
 
 ParamIterator::~ParamIterator() = default;
 
diff --git a/plugins/clang/codecompletion/context.cpp b/plugins/clang/codecompletion/context.cpp
--- a/plugins/clang/codecompletion/context.cpp
+++ b/plugins/clang/codecompletion/context.cpp
@@ -41,6 +41,7 @@
 #include <language/duchain/types/pointertype.h>
 #include <language/duchain/types/typealiastype.h>
 #include <language/duchain/types/typeutils.h>
+#include <language/duchain/stringhelpers.h>
 #include <language/codecompletion/codecompletionmodel.h>
 #include <language/codecompletion/normaldeclarationcompletionitem.h>
 #include <util/foregroundlock.h>
@@ -55,6 +56,7 @@
 #include "../duchain/navigationwidget.h"
 #include "../clangsettings/clangsettingsmanager.h"
 
+#include <algorithm>
 #include <functional>
 #include <memory>
 
@@ -338,7 +340,20 @@
 
     void execute(KTextEditor::View* view, const KTextEditor::Range& word) override
     {
-        view->document()->replaceText(word, m_replacement);
+        auto* const document = view->document();
+
+        // try and replace leading typed text that match the proposed implementation
+        const QString leading = document->line(word.end().line()).left(word.end().column());
+        const QString leadingNoSpace = removeWhitespace(leading);
+        if (!leadingNoSpace.isEmpty() && (removeWhitespace(m_display).startsWith(leadingNoSpace)
+            || removeWhitespace(m_replacement).startsWith(leadingNoSpace))) {
+            const int removeSize = leading.end() - std::find_if_not(leading.begin(), leading.end(),
+                                        [](QChar c){ return c.isSpace(); });
+            const KTextEditor::Cursor newStart = {word.end().line(), word.end().column() - removeSize};
+            document->replaceText({newStart, word.end()}, m_replacement);
+        } else {
+            document->replaceText(word, m_replacement);
+        }
     }
 };
 
diff --git a/plugins/clang/tests/test_codecompletion.cpp b/plugins/clang/tests/test_codecompletion.cpp
--- a/plugins/clang/tests/test_codecompletion.cpp
+++ b/plugins/clang/tests/test_codecompletion.cpp
@@ -1387,6 +1387,30 @@
         << CompletionItems({5, 0}, {"Test", "Test<X, B>::bar(B a)"})
         << "Test<X, B>::bar(B a)"
         << "template <template<class, int> class X, typename B>\nclass Test {\npublic:\nvoid bar(B a);\n};\ntemplate<template<typename, int> class X, typename B> void Test<X, B>::bar(B a)\n{\n}\n";
+
+    QTest::newRow("replace-leading-return-type")
+        << "void foo(int x);\nvoid "
+        << CompletionItems({1, 5}, {"foo(int x)"})
+        << "foo(int x)"
+        << "void foo(int x);\nvoid foo(int x)\n{\n}\n";
+
+    QTest::newRow("replace-leading-function-name")
+        << "void foo(int x);\nfoo"
+        << CompletionItems({1, 3}, {"foo(int x)"})
+        << "foo(int x)"
+        << "void foo(int x);\nvoid foo(int x)\n{\n}\n";
+
+    QTest::newRow("replace-leading-with-class-method")
+        << "class Foo { int bar(int x); };\nint "
+        << CompletionItems({1, 4}, {"Foo", "Foo::bar(int x)"})
+        << "Foo::bar(int x)"
+        << "class Foo { int bar(int x); };\nint Foo::bar(int x)\n{\n}\n";
+
+    QTest::newRow("replace-leading-whitespace-mismatch")
+        << "class Foo { int** bar(int x); };\nint * *"
+        << CompletionItems({1, 7}, {"** Foo::bar(int x)"})
+        << "** Foo::bar(int x)"
+        << "class Foo { int** bar(int x); };\nint ** Foo::bar(int x)\n{\n}\n";
 }
 
 void TestCodeCompletion::testIgnoreGccBuiltins()