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ExplicitResultTypes.scala
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ExplicitResultTypes.scala
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package scalafix.internal.rule
import scala.util.control.NonFatal
import scala.meta._
import scala.meta.contrib._
import scala.meta.internal.pc.ScalafixGlobal
import buildinfo.RulesBuildInfo
import metaconfig.Configured
import scalafix.internal.compat.CompilerCompat._
import scalafix.internal.v1.LazyValue
import scalafix.patch.Patch
import scalafix.util.TokenOps
import scalafix.v1._
final class ExplicitResultTypes(
config: ExplicitResultTypesConfig,
global: LazyValue[Option[ScalafixGlobal]]
) extends SemanticRule("ExplicitResultTypes") {
def this() = this(ExplicitResultTypesConfig.default, LazyValue.now(None))
val compilerScalaVersion: String = RulesBuildInfo.scalaVersion
private def toBinaryVersion(v: String) = v.split('.').take(2).mkString(".")
override def description: String =
"Inserts type annotations for inferred public members. " +
s"Only compatible with Scala 2.x."
override def isRewrite: Boolean = true
override def afterComplete(): Unit = {
shutdownCompiler()
}
private def shutdownCompiler(): Unit = {
global.foreach(_.foreach(g => {
try {
g.askShutdown()
g.closeCompat()
} catch {
case NonFatal(_) =>
}
}))
}
override def withConfiguration(config: Configuration): Configured[Rule] = {
val symbolReplacements =
config.conf.dynamic.ExplicitResultTypes.symbolReplacements
.as[Map[String, String]]
.getOrElse(Map.empty)
val newGlobal: LazyValue[Option[ScalafixGlobal]] =
if (config.scalacClasspath.isEmpty) {
LazyValue.now(None)
} else {
LazyValue.from { () =>
ScalafixGlobal.newCompiler(
config.scalacClasspath,
config.scalacOptions,
symbolReplacements
)
}
}
val inputBinaryScalaVersion =
toBinaryVersion(config.scalaVersion)
val runtimeBinaryScalaVersion =
toBinaryVersion(compilerScalaVersion)
if (
config.scalacClasspath.nonEmpty && inputBinaryScalaVersion != runtimeBinaryScalaVersion
) {
Configured.error(
s"The ExplicitResultTypes rule needs to run with the same Scala binary version as the one used to compile target sources ($inputBinaryScalaVersion). " +
s"To fix this problem, either remove ExplicitResultTypes from .scalafix.conf or make sure the scalafixScalaBinaryVersion setting key matches $inputBinaryScalaVersion."
)
} else {
config.conf // Support deprecated explicitReturnTypes config
.getOrElse("explicitReturnTypes", "ExplicitResultTypes")(
ExplicitResultTypesConfig.default
)
.map(c => new ExplicitResultTypes(c, newGlobal))
}
}
override def fix(implicit ctx: SemanticDocument): Patch =
try unsafeFix()
catch {
case _: CompilerException if !config.fatalWarnings =>
Patch.empty
}
def unsafeFix()(implicit ctx: SemanticDocument): Patch = {
global.value match {
case Some(value) =>
val types = new CompilerTypePrinter(value, config)
ctx.tree.collect {
case t @ Defn.Val(mods, Pat.Var(name) :: Nil, None, body)
if isRuleCandidate(t, name, mods, body) =>
fixDefinition(t, body, types)
case t @ Defn.Var(mods, Pat.Var(name) :: Nil, None, Some(body))
if isRuleCandidate(t, name, mods, body) =>
fixDefinition(t, body, types)
case t @ Defn.Def(mods, name, _, _, None, body)
if isRuleCandidate(t, name, mods, body) =>
fixDefinition(t, body, types)
}.asPatch
case None => Patch.empty
}
}
// Don't explicitly annotate vals when the right-hand body is a single call
// to `implicitly`. Prevents ambiguous implicit. Not annotating in such cases,
// this a common trick employed implicit-heavy code to workaround SI-2712.
// Context: https://gitter.im/typelevel/cats?at=584573151eb3d648695b4a50
private def isImplicitly(term: Term): Boolean = term match {
case Term.ApplyType(Term.Name("implicitly"), _) => true
case _ => false
}
def defnName(defn: Defn): Option[Name] = Option(defn).collect {
case Defn.Val(_, Pat.Var(name) :: Nil, _, _) => name
case Defn.Var(_, Pat.Var(name) :: Nil, _, _) => name
case Defn.Def(_, name, _, _, _, _) => name
}
def defnBody(defn: Defn): Option[Term] = Option(defn).collect {
case Defn.Val(_, _, _, term) => term
case Defn.Var(_, _, _, Some(term)) => term
case Defn.Def(_, _, _, _, _, term) => term
}
def visibility(mods: Iterable[Mod]): MemberVisibility =
mods
.collectFirst {
case _: Mod.Private => MemberVisibility.Private
case _: Mod.Protected => MemberVisibility.Protected
}
.getOrElse(MemberVisibility.Public)
def kind(defn: Defn): Option[MemberKind] = Option(defn).collect {
case _: Defn.Val => MemberKind.Val
case _: Defn.Def => MemberKind.Def
case _: Defn.Var => MemberKind.Var
}
def isRuleCandidate[D <: Defn](
defn: D,
nm: Name,
mods: Iterable[Mod],
body: Term
)(implicit ev: Extract[D, Mod], ctx: SemanticDocument): Boolean = {
import config._
def matchesMemberVisibility(): Boolean =
memberVisibility.contains(visibility(mods))
def matchesMemberKind(): Boolean =
kind(defn).exists(memberKind.contains)
def isFinalLiteralVal: Boolean =
defn.is[Defn.Val] &&
mods.exists(_.is[Mod.Final]) &&
body.is[Lit]
def matchesSimpleDefinition(): Boolean =
config.skipSimpleDefinitions.isSimpleDefinition(body)
def isImplicit: Boolean =
defn.hasMod(mod"implicit") && !isImplicitly(body)
def hasParentWihTemplate: Boolean =
defn.parent.exists(_.is[Template])
def qualifyingImplicit: Boolean =
isImplicit && !isFinalLiteralVal
def matchesMemberKindAndVisibility: Boolean =
matchesMemberKind && matchesMemberVisibility
def qualifyingNonImplicit: Boolean = {
!onlyImplicits &&
hasParentWihTemplate &&
!defn.hasMod(mod"implicit") &&
!matchesSimpleDefinition()
}
matchesMemberKindAndVisibility && {
qualifyingImplicit || qualifyingNonImplicit
}
}
def defnType(
defn: Defn,
replace: Token,
space: String,
types: CompilerTypePrinter
)(implicit
ctx: SemanticDocument
): Option[Patch] =
for {
name <- defnName(defn)
defnSymbol <- name.symbol.asNonEmpty
patch <- types.toPatch(name.pos, defnSymbol, replace, defn, space)
} yield patch
def fixDefinition(defn: Defn, body: Term, types: CompilerTypePrinter)(implicit
ctx: SemanticDocument
): Patch = {
val lst = ctx.tokenList
val option = SymbolMatcher.exact("scala/Option.")
val list = SymbolMatcher.exact(
"scala/package.List.",
"scala/collection/immutable/List."
)
val seq = SymbolMatcher.exact(
"scala/package.Seq.",
"scala/collection/Seq.",
"scala/collection/immutable/Seq."
)
def patchEmptyValue(term: Term): Patch = {
term match {
case q"${option(_)}.empty[$_]" =>
Patch.replaceTree(term, "None")
case q"${list(_)}.empty[$_]" =>
Patch.replaceTree(term, "Nil")
case q"${seq(_)}.empty[$_]" =>
Patch.replaceTree(term, "Nil")
case _ =>
Patch.empty
}
}
import lst._
for {
start <- defn.tokens.headOption
end <- body.tokens.headOption
// Left-hand side tokens in definition.
// Example: `val x = ` from `val x = rhs.banana`
lhsTokens = slice(start, end)
replace <- lhsTokens.reverseIterator.find(x =>
!x.is[Token.Equals] && !x.is[Trivia]
)
space = {
if (TokenOps.needsLeadingSpaceBeforeColon(replace)) " "
else ""
}
typePatch <- defnType(defn, replace, space, types)
valuePatchOpt = defnBody(defn).map(patchEmptyValue)
} yield typePatch + valuePatchOpt
}.asPatch.atomic
}