Added WhileTrue and InterpolationToString

input/src/main/scala/fix/InterpolationToString.scala

@@ -0,0 +1,20 @@
+/*
+rule = InterpolationToString
+ */
+package fix
+
+object InterpolationToString {
+
+  val a = 1
+  println(s" ${a.toString} b c ") // assert: InterpolationToString
+  println(s" ${2.toString} b ") // assert: InterpolationToString
+
+  println(f"${2.toString} b") // assert: InterpolationToString
+  println(f"${a.toString} b") // assert: InterpolationToString
+
+  println(s" $a b c ") // scalafix: ok;
+  println(f"$a b") // scalafix: ok;
+
+  println(s"${a == 2} b") // scalafix: ok;
+  println(s"${a == 2} b") // scalafix: ok;
+}

input/src/main/scala/fix/WhileTrue.scala

@@ -0,0 +1,16 @@
+/*
+rule = WhileTrue
+ */
+package fix
+
+object WhileTrue {
+
+  while (true) { // assert: WhileTrue
+    println("sam")
+  }
+
+  while (System.currentTimeMillis > 0) { // scalafix: ok;
+    println("sam")
+  }
+
+}

rules/src/main/resources/META-INF/services/scalafix.v1.Rule

@@ -45,4 +45,6 @@ fix.UnnecessaryConversion
 fix.UnreachableCatch
 fix.UnusedMethodParameter
 fix.VarCouldBeVal
-fix.VariableShadowing
+fix.VariableShadowing
+fix.WhileTrue
+fix.InterpolationToString

rules/src/main/scala/fix/InterpolationToString.scala

@@ -0,0 +1,32 @@
+/*
+rule = InterpolationToString
+ */
+package fix
+
+import scalafix.lint.LintSeverity
+import scalafix.v1._
+
+import scala.meta._
+
+class InterpolationToString extends SemanticRule("InterpolationToString") {
+
+  private def diag(pos: Position) = Diagnostic(
+    "",
+    "Checks for string interpolations that have .toString in their arguments",
+    pos,
+    "A call to .toString is not necessary, since arguments in format strings will be replaced by the value of a toString call on them.",
+    LintSeverity.Warning
+  )
+
+  override def fix(implicit doc: SemanticDocument): Patch = {
+    doc.tree.collect {
+      case Term.Interpolate(_, _, args) =>
+        args.collect {
+          // Corresponds to ${x.toString()} or ${x.toString} arguments in string interpolations
+          case t @ Term.Block(List(Term.Apply.After_4_6_0(Term.Select(_, Term.Name("toString")), _) | Term.Select(_, Term.Name("toString")))) => Patch.lint(diag(t.pos))
+          case _                                                                                                                              => Patch.empty
+        }
+      case _ => List(Patch.empty)
+    }.flatten.asPatch
+  }
+}

rules/src/main/scala/fix/WhileTrue.scala

@@ -0,0 +1,28 @@
+/*
+rule = WhileTrue
+ */
+package fix
+
+import scalafix.lint.LintSeverity
+import scalafix.v1._
+
+import scala.meta._
+
+class WhileTrue extends SemanticRule("WhileTrue") {
+
+  private def diag(pos: Position) = Diagnostic(
+    "",
+    "Checks for code that uses a while(true) block.",
+    pos,
+    "A while true loop is unlikely to be meant for production.",
+    LintSeverity.Warning
+  )
+
+  override def fix(implicit doc: SemanticDocument): Patch = {
+    doc.tree.collect {
+      case w @ Term.While(Lit.Boolean(true), _) => Patch.lint(diag(w.pos))
+      // This is only for compatibility with Scala version < 3. Do-while support has been dropped in Scala 3
+      case d @ Term.Do(_, Lit.Boolean(true)) => Patch.lint(diag(d.pos))
+    }.asPatch
+  }
+}