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| 1 | +package dotty.tools.pc |
| 2 | + |
| 3 | +import scala.util.Try |
| 4 | + |
| 5 | +import dotty.tools.dotc.ast.Trees.ValDef |
| 6 | +import dotty.tools.dotc.ast.tpd.* |
| 7 | +import dotty.tools.dotc.core.Contexts.Context |
| 8 | +import dotty.tools.dotc.core.Flags |
| 9 | +import dotty.tools.dotc.core.Flags.Method |
| 10 | +import dotty.tools.dotc.core.Names.Name |
| 11 | +import dotty.tools.dotc.core.StdNames.* |
| 12 | +import dotty.tools.dotc.core.SymDenotations.NoDenotation |
| 13 | +import dotty.tools.dotc.core.Symbols.defn |
| 14 | +import dotty.tools.dotc.core.Symbols.NoSymbol |
| 15 | +import dotty.tools.dotc.core.Symbols.Symbol |
| 16 | +import dotty.tools.dotc.core.Types.* |
| 17 | +import dotty.tools.pc.IndexedContext |
| 18 | +import dotty.tools.pc.utils.InteractiveEnrichments.* |
| 19 | +import scala.annotation.tailrec |
| 20 | +import dotty.tools.dotc.core.Denotations.SingleDenotation |
| 21 | +import dotty.tools.dotc.core.Denotations.MultiDenotation |
| 22 | +import dotty.tools.dotc.util.Spans.Span |
| 23 | + |
| 24 | +object ApplyExtractor: |
| 25 | + def unapply(path: List[Tree])(using Context): Option[Apply] = |
| 26 | + path match |
| 27 | + case ValDef(_, _, _) :: Block(_, app: Apply) :: _ |
| 28 | + if !app.fun.isInfix => Some(app) |
| 29 | + case rest => |
| 30 | + def getApplyForContextFunctionParam(path: List[Tree]): Option[Apply] = |
| 31 | + path match |
| 32 | + // fun(arg@@) |
| 33 | + case (app: Apply) :: _ => Some(app) |
| 34 | + // fun(arg@@), where fun(argn: Context ?=> SomeType) |
| 35 | + // recursively matched for multiple context arguments, e.g. Context1 ?=> Context2 ?=> SomeType |
| 36 | + case (_: DefDef) :: Block(List(_), _: Closure) :: rest => |
| 37 | + getApplyForContextFunctionParam(rest) |
| 38 | + case _ => None |
| 39 | + for |
| 40 | + app <- getApplyForContextFunctionParam(rest) |
| 41 | + if !app.fun.isInfix |
| 42 | + yield app |
| 43 | + end match |
| 44 | + |
| 45 | + |
| 46 | +object ApplyArgsExtractor: |
| 47 | + def getArgsAndParams( |
| 48 | + optIndexedContext: Option[IndexedContext], |
| 49 | + apply: Apply, |
| 50 | + span: Span |
| 51 | + )(using Context): List[(List[Tree], List[ParamSymbol])] = |
| 52 | + def collectArgss(a: Apply): List[List[Tree]] = |
| 53 | + def stripContextFuntionArgument(argument: Tree): List[Tree] = |
| 54 | + argument match |
| 55 | + case Block(List(d: DefDef), _: Closure) => |
| 56 | + d.rhs match |
| 57 | + case app: Apply => |
| 58 | + app.args |
| 59 | + case b @ Block(List(_: DefDef), _: Closure) => |
| 60 | + stripContextFuntionArgument(b) |
| 61 | + case _ => Nil |
| 62 | + case v => List(v) |
| 63 | + |
| 64 | + val args = a.args.flatMap(stripContextFuntionArgument) |
| 65 | + a.fun match |
| 66 | + case app: Apply => collectArgss(app) :+ args |
| 67 | + case _ => List(args) |
| 68 | + end collectArgss |
| 69 | + |
| 70 | + val method = apply.fun |
| 71 | + |
| 72 | + val argss = collectArgss(apply) |
| 73 | + |
| 74 | + def fallbackFindApply(sym: Symbol) = |
| 75 | + sym.info.member(nme.apply) match |
| 76 | + case NoDenotation => Nil |
| 77 | + case den => List(den.symbol) |
| 78 | + |
| 79 | + // fallback for when multiple overloaded methods match the supplied args |
| 80 | + def fallbackFindMatchingMethods() = |
| 81 | + def matchingMethodsSymbols( |
| 82 | + indexedContext: IndexedContext, |
| 83 | + method: Tree |
| 84 | + ): List[Symbol] = |
| 85 | + method match |
| 86 | + case Ident(name) => indexedContext.findSymbol(name).getOrElse(Nil) |
| 87 | + case Select(This(_), name) => indexedContext.findSymbol(name).getOrElse(Nil) |
| 88 | + case sel @ Select(from, name) => |
| 89 | + val symbol = from.symbol |
| 90 | + val ownerSymbol = |
| 91 | + if symbol.is(Method) && symbol.owner.isClass then |
| 92 | + Some(symbol.owner) |
| 93 | + else Try(symbol.info.classSymbol).toOption |
| 94 | + ownerSymbol.map(sym => sym.info.member(name)).collect{ |
| 95 | + case single: SingleDenotation => List(single.symbol) |
| 96 | + case multi: MultiDenotation => multi.allSymbols |
| 97 | + }.getOrElse(Nil) |
| 98 | + case Apply(fun, _) => matchingMethodsSymbols(indexedContext, fun) |
| 99 | + case _ => Nil |
| 100 | + val matchingMethods = |
| 101 | + for |
| 102 | + indexedContext <- optIndexedContext.toList |
| 103 | + potentialMatch <- matchingMethodsSymbols(indexedContext, method) |
| 104 | + if potentialMatch.is(Flags.Method) && |
| 105 | + potentialMatch.vparamss.length >= argss.length && |
| 106 | + Try(potentialMatch.isAccessibleFrom(apply.symbol.info)).toOption |
| 107 | + .getOrElse(false) && |
| 108 | + potentialMatch.vparamss |
| 109 | + .zip(argss) |
| 110 | + .reverse |
| 111 | + .zipWithIndex |
| 112 | + .forall { case (pair, index) => |
| 113 | + FuzzyArgMatcher(potentialMatch.tparams) |
| 114 | + .doMatch(allArgsProvided = index != 0, span) |
| 115 | + .tupled(pair) |
| 116 | + } |
| 117 | + yield potentialMatch |
| 118 | + matchingMethods |
| 119 | + end fallbackFindMatchingMethods |
| 120 | + |
| 121 | + val matchingMethods: List[Symbol] = |
| 122 | + if method.symbol.paramSymss.nonEmpty then |
| 123 | + val allArgsAreSupplied = |
| 124 | + val vparamss = method.symbol.vparamss |
| 125 | + vparamss.length == argss.length && vparamss |
| 126 | + .zip(argss) |
| 127 | + .lastOption |
| 128 | + .exists { case (baseParams, baseArgs) => |
| 129 | + baseArgs.length == baseParams.length |
| 130 | + } |
| 131 | + // ``` |
| 132 | + // m(arg : Int) |
| 133 | + // m(arg : Int, anotherArg : Int) |
| 134 | + // m(a@@) |
| 135 | + // ``` |
| 136 | + // complier will choose the first `m`, so we need to manually look for the other one |
| 137 | + if allArgsAreSupplied then |
| 138 | + val foundPotential = fallbackFindMatchingMethods() |
| 139 | + if foundPotential.contains(method.symbol) then foundPotential |
| 140 | + else method.symbol :: foundPotential |
| 141 | + else List(method.symbol) |
| 142 | + else if method.symbol.is(Method) || method.symbol == NoSymbol then |
| 143 | + fallbackFindMatchingMethods() |
| 144 | + else fallbackFindApply(method.symbol) |
| 145 | + end if |
| 146 | + end matchingMethods |
| 147 | + |
| 148 | + matchingMethods.map { methodSym => |
| 149 | + val vparamss = methodSym.vparamss |
| 150 | + |
| 151 | + // get params and args we are interested in |
| 152 | + // e.g. |
| 153 | + // in the following case, the interesting args and params are |
| 154 | + // - params: [apple, banana] |
| 155 | + // - args: [apple, b] |
| 156 | + // ``` |
| 157 | + // def curry(x: Int)(apple: String, banana: String) = ??? |
| 158 | + // curry(1)(apple = "test", b@@) |
| 159 | + // ``` |
| 160 | + val (baseParams0, baseArgs) = |
| 161 | + vparamss.zip(argss).lastOption.getOrElse((Nil, Nil)) |
| 162 | + |
| 163 | + val baseParams: List[ParamSymbol] = |
| 164 | + def defaultBaseParams = baseParams0.map(JustSymbol(_)) |
| 165 | + @tailrec |
| 166 | + def getRefinedParams(refinedType: Type, level: Int): List[ParamSymbol] = |
| 167 | + if level > 0 then |
| 168 | + val resultTypeOpt = |
| 169 | + refinedType match |
| 170 | + case RefinedType(AppliedType(_, args), _, _) => args.lastOption |
| 171 | + case AppliedType(_, args) => args.lastOption |
| 172 | + case _ => None |
| 173 | + resultTypeOpt match |
| 174 | + case Some(resultType) => getRefinedParams(resultType, level - 1) |
| 175 | + case _ => defaultBaseParams |
| 176 | + else |
| 177 | + refinedType match |
| 178 | + case RefinedType(AppliedType(_, args), _, MethodType(ri)) => |
| 179 | + baseParams0.zip(ri).zip(args).map { case ((sym, name), arg) => |
| 180 | + RefinedSymbol(sym, name, arg) |
| 181 | + } |
| 182 | + case _ => defaultBaseParams |
| 183 | + // finds param refinements for lambda expressions |
| 184 | + // val hello: (x: Int, y: Int) => Unit = (x, _) => println(x) |
| 185 | + @tailrec |
| 186 | + def refineParams(method: Tree, level: Int): List[ParamSymbol] = |
| 187 | + method match |
| 188 | + case Select(Apply(f, _), _) => refineParams(f, level + 1) |
| 189 | + case Select(h, name) => |
| 190 | + // for Select(foo, name = apply) we want `foo.symbol` |
| 191 | + if name == nme.apply then getRefinedParams(h.symbol.info, level) |
| 192 | + else getRefinedParams(method.symbol.info, level) |
| 193 | + case Apply(f, _) => |
| 194 | + refineParams(f, level + 1) |
| 195 | + case _ => getRefinedParams(method.symbol.info, level) |
| 196 | + refineParams(method, 0) |
| 197 | + end baseParams |
| 198 | + (baseArgs, baseParams) |
| 199 | + } |
| 200 | + |
| 201 | + extension (method: Symbol) |
| 202 | + def vparamss(using Context) = method.filteredParamss(_.isTerm) |
| 203 | + def tparams(using Context) = method.filteredParamss(_.isType).flatten |
| 204 | + def filteredParamss(f: Symbol => Boolean)(using Context) = |
| 205 | + method.paramSymss.filter(params => params.forall(f)) |
| 206 | +sealed trait ParamSymbol: |
| 207 | + def name: Name |
| 208 | + def info: Type |
| 209 | + def symbol: Symbol |
| 210 | + def nameBackticked(using Context) = name.decoded.backticked |
| 211 | + |
| 212 | +case class JustSymbol(symbol: Symbol)(using Context) extends ParamSymbol: |
| 213 | + def name: Name = symbol.name |
| 214 | + def info: Type = symbol.info |
| 215 | + |
| 216 | +case class RefinedSymbol(symbol: Symbol, name: Name, info: Type) |
| 217 | + extends ParamSymbol |
| 218 | + |
| 219 | + |
| 220 | +class FuzzyArgMatcher(tparams: List[Symbol])(using Context): |
| 221 | + |
| 222 | + /** |
| 223 | + * A heuristic for checking if the passed arguments match the method's arguments' types. |
| 224 | + * For non-polymorphic methods we use the subtype relation (`<:<`) |
| 225 | + * and for polymorphic methods we use a heuristic. |
| 226 | + * We check the args types not the result type. |
| 227 | + */ |
| 228 | + def doMatch( |
| 229 | + allArgsProvided: Boolean, |
| 230 | + span: Span |
| 231 | + )(expectedArgs: List[Symbol], actualArgs: List[Tree]) = |
| 232 | + (expectedArgs.length == actualArgs.length || |
| 233 | + (!allArgsProvided && expectedArgs.length >= actualArgs.length)) && |
| 234 | + actualArgs.zipWithIndex.forall { |
| 235 | + case (arg: Ident, _) if arg.span.contains(span) => true |
| 236 | + case (NamedArg(name, arg), _) => |
| 237 | + expectedArgs.exists { expected => |
| 238 | + expected.name == name && (!arg.hasType || arg.typeOpt.unfold |
| 239 | + .fuzzyArg_<:<(expected.info)) |
| 240 | + } |
| 241 | + case (arg, i) => |
| 242 | + !arg.hasType || arg.typeOpt.unfold.fuzzyArg_<:<(expectedArgs(i).info) |
| 243 | + } |
| 244 | + |
| 245 | + extension (arg: Type) |
| 246 | + def fuzzyArg_<:<(expected: Type) = |
| 247 | + if tparams.isEmpty then arg <:< expected |
| 248 | + else arg <:< substituteTypeParams(expected) |
| 249 | + def unfold = |
| 250 | + arg match |
| 251 | + case arg: TermRef => arg.underlying |
| 252 | + case e => e |
| 253 | + |
| 254 | + private def substituteTypeParams(t: Type): Type = |
| 255 | + t match |
| 256 | + case e if tparams.exists(_ == e.typeSymbol) => |
| 257 | + val matchingParam = tparams.find(_ == e.typeSymbol).get |
| 258 | + matchingParam.info match |
| 259 | + case b @ TypeBounds(_, _) => WildcardType(b) |
| 260 | + case _ => WildcardType |
| 261 | + case o @ OrType(e1, e2) => |
| 262 | + OrType(substituteTypeParams(e1), substituteTypeParams(e2), o.isSoft) |
| 263 | + case AndType(e1, e2) => |
| 264 | + AndType(substituteTypeParams(e1), substituteTypeParams(e2)) |
| 265 | + case AppliedType(et, eparams) => |
| 266 | + AppliedType(et, eparams.map(substituteTypeParams)) |
| 267 | + case _ => t |
| 268 | + |
| 269 | +end FuzzyArgMatcher |
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