"Remove parameter" quick fix: remove also type constraint

#KT-26673 Fixed

idea/src/org/jetbrains/kotlin/idea/quickfix/RemoveUnusedFunctionParameterFix.kt

@@ -23,7 +23,9 @@ import org.jetbrains.kotlin.diagnostics.Diagnostic
 import org.jetbrains.kotlin.diagnostics.Errors
 import org.jetbrains.kotlin.idea.caches.resolve.resolveToParameterDescriptorIfAny
 import org.jetbrains.kotlin.idea.intentions.RemoveEmptyPrimaryConstructorIntention
+import org.jetbrains.kotlin.idea.references.KtSimpleNameReference
 import org.jetbrains.kotlin.idea.util.application.runWriteAction
+import org.jetbrains.kotlin.lexer.KtTokens
 import org.jetbrains.kotlin.psi.*
 import org.jetbrains.kotlin.psi.psiUtil.*
 import org.jetbrains.kotlin.resolve.lazy.BodyResolveMode
@@ -91,11 +93,22 @@ class RemoveUnusedFunctionParameterFix(parameter: KtParameter) : KotlinQuickFixA
         }
 
         fun runRemoveUnusedTypeParameters(typeParameters: List<KtTypeParameter>) {
-            val unusedTypeParams = typeParameters.filter { ReferencesSearch.search(it).findFirst() == null }
+            val unusedTypeParams = typeParameters.filter { typeParameter ->
+                ReferencesSearch.search(typeParameter).none { (it as? KtSimpleNameReference)?.expression?.parent !is KtTypeConstraint }
+            }
             if (unusedTypeParams.isEmpty()) return
             runWriteAction {
                 unusedTypeParams.forEach { typeParameter ->
                     val typeParameterList = typeParameter.parent as? KtTypeParameterList ?: return@forEach
+                    val typeConstraintList = typeParameterList.parent.getChildOfType<KtTypeConstraintList>()
+                    if (typeConstraintList != null) {
+                        val typeConstraint = typeConstraintList.constraints.find { it.subjectTypeParameterName?.text == typeParameter.text }
+                        if (typeConstraint != null) EditCommaSeparatedListHelper.removeItem(typeConstraint)
+                        if (typeConstraintList.constraints.size == 0) {
+                            val prev = typeConstraintList.getPrevSiblingIgnoringWhitespaceAndComments()
+                            if (prev?.node?.elementType == KtTokens.WHERE_KEYWORD) prev?.delete()
+                        }
+                    }
                     if (typeParameterList.parameters.size == 1)
                         typeParameterList.delete()
                     else

idea/testData/quickfix/changeSignature/removeUnusedParameterWithTypeParameterAndTypeConstraint.kt

@@ -0,0 +1,6 @@
+// "Remove parameter 'x'" "true"
+fun <X> foo(<caret>x: X) where X : Number {}
+
+fun test() {
+    foo(1)
+}

idea/testData/quickfix/changeSignature/removeUnusedParameterWithTypeParameterAndTypeConstraint.kt.after

@@ -0,0 +1,6 @@
+// "Remove parameter 'x'" "true"
+fun foo() {}
+
+fun test() {
+    foo()
+}

idea/testData/quickfix/changeSignature/removeUnusedParameterWithTypeParameterAndTypeConstraint2.kt

@@ -0,0 +1,6 @@
+// "Remove parameter 'x'" "true"
+fun <X, Y> bar(<caret>x: X, y: Y) where X : Number, Y : Number {}
+
+fun test() {
+    bar(1, 2)
+}

idea/testData/quickfix/changeSignature/removeUnusedParameterWithTypeParameterAndTypeConstraint2.kt.after

@@ -0,0 +1,6 @@
+// "Remove parameter 'x'" "true"
+fun <Y> bar(y: Y) where Y : Number {}
+
+fun test() {
+    bar(2)
+}

idea/tests/org/jetbrains/kotlin/idea/quickfix/QuickFixTestGenerated.java

@@ -1866,6 +1866,16 @@ public class QuickFixTestGenerated extends AbstractQuickFixTest {
             runTest("idea/testData/quickfix/changeSignature/removeUnusedParameterWithTypeParameter7.kt");
         }
 
+        @TestMetadata("removeUnusedParameterWithTypeParameterAndTypeConstraint.kt")
+        public void testRemoveUnusedParameterWithTypeParameterAndTypeConstraint() throws Exception {
+            runTest("idea/testData/quickfix/changeSignature/removeUnusedParameterWithTypeParameterAndTypeConstraint.kt");
+        }
+
+        @TestMetadata("removeUnusedParameterWithTypeParameterAndTypeConstraint2.kt")
+        public void testRemoveUnusedParameterWithTypeParameterAndTypeConstraint2() throws Exception {
+            runTest("idea/testData/quickfix/changeSignature/removeUnusedParameterWithTypeParameterAndTypeConstraint2.kt");
+        }
+
         @TestMetadata("removeUnusedPrimaryConstructorParameter.kt")
         public void testRemoveUnusedPrimaryConstructorParameter() throws Exception {
             runTest("idea/testData/quickfix/changeSignature/removeUnusedPrimaryConstructorParameter.kt");