From 14fde01d3576f60585d59d2b00cce8b3c177b236 Mon Sep 17 00:00:00 2001 From: Martin Odersky Date: Sun, 9 Apr 2017 19:08:52 +0200 Subject: Fix #2192: Fullow supertypes when determining whether an expect type is a function type --- compiler/src/dotty/tools/dotc/typer/Typer.scala | 14 ++++++++++++-- 1 file changed, 12 insertions(+), 2 deletions(-) (limited to 'compiler/src/dotty/tools/dotc/typer/Typer.scala') diff --git a/compiler/src/dotty/tools/dotc/typer/Typer.scala b/compiler/src/dotty/tools/dotc/typer/Typer.scala index 2760ceba9..a7b8200b5 100644 --- a/compiler/src/dotty/tools/dotc/typer/Typer.scala +++ b/compiler/src/dotty/tools/dotc/typer/Typer.scala @@ -1932,13 +1932,23 @@ class Typer extends Namer with TypeAssigner with Applications with Implicits wit adapt(typed(original, WildcardType), pt, EmptyTree) } case wtp: MethodType if !pt.isInstanceOf[SingletonType] => + // Follow proxies and approximate type paramrefs by their upper bound + // in the current constraint in order to figure out robustly + // whether an expected type is some sort of function type. + def underlyingRefined(tp: Type): Type = tp.stripTypeVar match { + case tp: RefinedType => tp + case tp: TypeParamRef => underlyingRefined(ctx.typeComparer.bounds(tp).hi) + case tp: TypeProxy => underlyingRefined(tp.superType) + case _ => tp + } + val ptNorm = underlyingRefined(pt) val arity = - if (defn.isFunctionType(pt)) + if (defn.isFunctionType(ptNorm)) if (!isFullyDefined(pt, ForceDegree.none) && isFullyDefined(wtp, ForceDegree.none)) // if method type is fully defined, but expected type is not, // prioritize method parameter types as parameter types of the eta-expanded closure 0 - else defn.functionArity(pt) + else defn.functionArity(ptNorm) else if (pt eq AnyFunctionProto) wtp.paramInfos.length else -1 if (arity >= 0 && !tree.symbol.isConstructor) -- cgit v1.2.3