diff --git a/python/src/com/jetbrains/python/inspections/quickfix/PyChangeSignatureQuickFix.java b/python/src/com/jetbrains/python/inspections/quickfix/PyChangeSignatureQuickFix.java
index f5ceff9d9893..ec2f531832ba 100644
--- a/python/src/com/jetbrains/python/inspections/quickfix/PyChangeSignatureQuickFix.java
+++ b/python/src/com/jetbrains/python/inspections/quickfix/PyChangeSignatureQuickFix.java
@@ -76,20 +76,14 @@ public class PyChangeSignatureQuickFix extends LocalQuickFixOnPsiElement {
     final Set<String> usedParamNames = new HashSet<>();
     for (PyExpression arg : mapping.getUnmappedArguments()) {
       if (arg instanceof PyKeywordArgument) {
-        final String defaultValueText;
         final PyExpression value = ((PyKeywordArgument)arg).getValueExpression();
-        if (value != null && PyRefactoringUtil.isSimpleExpression(value) && !value.textContains('\n')) {
-          defaultValueText = value.getText();
-        }
-        else {
-          defaultValueText = ApplicationManager.getApplication().isUnitTestMode() ? "None" : "";
-        }
+        final String valueText = value != null ? value.getText() : "";
         newParameters.add(Pair.create(parameters.length - 1,
-                                      new PyParameterInfo(-1, ((PyKeywordArgument)arg).getKeyword(), defaultValueText, true)));
+                                      new PyParameterInfo(-1, ((PyKeywordArgument)arg).getKeyword(), valueText, true)));
       }
       else {
         final String paramName = generateParameterName(arg, function, usedParamNames, context);
-        newParameters.add(Pair.create(positionalParamAnchor, new PyParameterInfo(-1, paramName, "", false)));
+        newParameters.add(Pair.create(positionalParamAnchor, new PyParameterInfo(-1, paramName, arg.getText(), false)));
         usedParamNames.add(paramName);
       }
     }
@@ -109,12 +103,15 @@ public class PyChangeSignatureQuickFix extends LocalQuickFixOnPsiElement {
     }
     return new PyChangeSignatureQuickFix(function, extraParams, null);
   }
-
-
+  
   private final List<Pair<Integer, PyParameterInfo>> myExtraParameters;
   private final SmartPsiElementPointer<PyCallExpression> myOriginalCallExpression;
 
 
+  /**
+   * @param extraParameters new parameters anchored by indexes of the existing parameters they should be inserted <em>after</em>
+   *                        (-1 in case they should precede the first parameter)
+   */
   public PyChangeSignatureQuickFix(@NotNull PyFunction function,
                                    @NotNull List<Pair<Integer, PyParameterInfo>> extraParameters,
                                    @Nullable PyCallExpression expression) {
diff --git a/python/src/com/jetbrains/python/refactoring/PyRefactoringUtil.java b/python/src/com/jetbrains/python/refactoring/PyRefactoringUtil.java
index 14592a8abbe1..4448804a780c 100644
--- a/python/src/com/jetbrains/python/refactoring/PyRefactoringUtil.java
+++ b/python/src/com/jetbrains/python/refactoring/PyRefactoringUtil.java
@@ -17,7 +17,6 @@ package com.jetbrains.python.refactoring;
 
 import com.intellij.codeInsight.PsiEquivalenceUtil;
 import com.intellij.find.findUsages.FindUsagesHandler;
-import com.intellij.lang.ASTNode;
 import com.intellij.openapi.project.Project;
 import com.intellij.openapi.util.Comparing;
 import com.intellij.openapi.util.Pair;
@@ -29,7 +28,6 @@ import com.intellij.usageView.UsageInfo;
 import com.intellij.util.containers.ContainerUtil;
 import com.intellij.util.containers.HashSet;
 import com.jetbrains.python.PyNames;
-import com.jetbrains.python.PyTokenTypes;
 import com.jetbrains.python.findUsages.PyFindUsagesHandlerFactory;
 import com.jetbrains.python.psi.*;
 import com.jetbrains.python.refactoring.introduce.IntroduceValidator;
@@ -399,16 +397,4 @@ public class PyRefactoringUtil {
   public static boolean isValidNewName(@NotNull String name, @NotNull PsiElement scopeAnchor) {
     return !(IntroduceValidator.isDefinedInScope(name, scopeAnchor) || PyNames.isReserved(name));
   }
-
-  public static boolean isSimpleExpression(@NotNull PyExpression value) {
-    if (value instanceof PyLiteralExpression) {
-      final ASTNode node = value.getNode();
-      // Check that string literal doesn't contain multiple glued nodes
-      return node.getChildren(null).length == 1 && PyTokenTypes.SCALAR_LITERALS.contains(node.getFirstChildNode().getElementType());  
-    }
-    else if (value instanceof PyReferenceExpression) {
-      return PyUtil.isPy2ReservedWord((PyReferenceExpression)value);
-    }
-    return false;
-  }
 }
diff --git a/python/testData/inspections/AddParameterDefaultValues.py b/python/testData/inspections/AddParameterDefaultValues.py
new file mode 100644
index 000000000000..eceee62d0ccc
--- /dev/null
+++ b/python/testData/inspections/AddParameterDefaultValues.py
@@ -0,0 +1,6 @@
+def func():
+    pass
+
+
+func<warning descr="Unexpected argument(s)">(<caret><warning descr="Unexpected argument">42</warning>, <warning descr="Unexpected argument">foo='spam'</warning>)</warning>
+func()
diff --git a/python/testData/inspections/AddParameterDefaultValues_after.py b/python/testData/inspections/AddParameterDefaultValues_after.py
new file mode 100644
index 000000000000..046a292bc48c
--- /dev/null
+++ b/python/testData/inspections/AddParameterDefaultValues_after.py
@@ -0,0 +1,6 @@
+def func(i, foo='spam'):
+    pass
+
+
+func(42, foo='spam')
+func(42)
diff --git a/python/testSrc/com/jetbrains/python/PyQuickFixTest.java b/python/testSrc/com/jetbrains/python/PyQuickFixTest.java
index 2c18d8f19bce..2f07cca791a7 100644
--- a/python/testSrc/com/jetbrains/python/PyQuickFixTest.java
+++ b/python/testSrc/com/jetbrains/python/PyQuickFixTest.java
@@ -657,6 +657,11 @@ public class PyQuickFixTest extends PyTestCase {
     doInspectionTest(PyArgumentListInspection.class, "<html>Change signature of", true, true);
   }
 
+  // PY-8174
+  public void testAddParameterDefaultValues() {
+    doInspectionTest(PyArgumentListInspection.class, "<html>Change signature of", true, true);
+  }
+
   @Override
   @NonNls
   protected String getTestDataPath() {