Add inspection (INFORMATION) to convert Pair constructor into to call

So #KT-22933 Fixed

idea/src/META-INF/plugin.xml

@@ -2734,6 +2734,15 @@
                      language="kotlin"
     />
 
+    <localInspection implementationClass="org.jetbrains.kotlin.idea.inspections.ConvertPairConstructorToToFunctionInspection"
+                     displayName="Convert Pair constructor to 'to' function"
+                     groupPath="Kotlin"
+                     groupName="Style issues"
+                     enabledByDefault="true"
+                     level="INFORMATION"
+                     language="kotlin"
+    />
+
     <referenceImporter implementation="org.jetbrains.kotlin.idea.quickfix.KotlinReferenceImporter"/>
 
     <fileType.fileViewProviderFactory filetype="KJSM" implementationClass="com.intellij.psi.ClassFileViewProviderFactory"/>

idea/src/org/jetbrains/kotlin/idea/inspections/ConvertPairConstructorToToFunctionInspection.kt

@@ -0,0 +1,53 @@
+/*
+ * Copyright 2000-2018 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license
+ * that can be found in the license/LICENSE.txt file.
+ */
+
+package org.jetbrains.kotlin.idea.inspections
+
+import com.intellij.codeInspection.LocalQuickFix
+import com.intellij.codeInspection.ProblemDescriptor
+import com.intellij.codeInspection.ProblemHighlightType
+import com.intellij.codeInspection.ProblemsHolder
+import com.intellij.openapi.project.Project
+import com.intellij.psi.PsiElementVisitor
+import org.jetbrains.kotlin.idea.intentions.getCallableDescriptor
+import org.jetbrains.kotlin.name.FqName
+import org.jetbrains.kotlin.psi.KtCallExpression
+import org.jetbrains.kotlin.psi.KtPsiFactory
+import org.jetbrains.kotlin.psi.callExpressionVisitor
+import org.jetbrains.kotlin.psi.createExpressionByPattern
+import org.jetbrains.kotlin.resolve.descriptorUtil.fqNameSafe
+
+class ConvertPairConstructorToToFunctionInspection : AbstractKotlinInspection() {
+    override fun buildVisitor(holder: ProblemsHolder, isOnTheFly: Boolean): PsiElementVisitor {
+        return callExpressionVisitor { expression ->
+            if (expression.isPairConstructorCall()) {
+                holder.registerProblem(
+                    expression,
+                    "Can be converted to 'to'",
+                    ProblemHighlightType.INFORMATION,
+                    ConvertPairConstructorToToFix()
+                )
+            }
+        }
+    }
+}
+
+private class ConvertPairConstructorToToFix : LocalQuickFix {
+    override fun getName() = "Convert to 'to'"
+
+    override fun getFamilyName() = name
+
+    override fun applyFix(project: Project, descriptor: ProblemDescriptor) {
+        val expression = descriptor.psiElement as? KtCallExpression ?: return
+        val args = expression.valueArguments.mapNotNull { it.getArgumentExpression() }.toTypedArray()
+        expression.replace(KtPsiFactory(expression).createExpressionByPattern("$0 to $1", *args))
+    }
+}
+
+private fun KtCallExpression.isPairConstructorCall(): Boolean {
+    if (valueArguments.size != 2) return false
+    if (valueArguments.mapNotNull { it.getArgumentExpression() }.size != 2) return false
+    return getCallableDescriptor()?.containingDeclaration?.fqNameSafe == FqName("kotlin.Pair")
+}