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author | Martin Odersky <odersky@gmail.com> | 2016-02-16 13:46:46 +0100 |
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committer | Martin Odersky <odersky@gmail.com> | 2016-02-16 13:46:46 +0100 |
commit | c4be2191e0c17767911377d7bc835d1b40eb39af (patch) | |
tree | 38e7586809bc3520b31f5a64f8f4f5c53ddc9b27 /src/dotty/tools/dotc/typer/Typer.scala | |
parent | afec2a7a597e6e7736e4d26620f8488e9587b7b0 (diff) | |
download | dotty-c4be2191e0c17767911377d7bc835d1b40eb39af.tar.gz dotty-c4be2191e0c17767911377d7bc835d1b40eb39af.tar.bz2 dotty-c4be2191e0c17767911377d7bc835d1b40eb39af.zip |
Handle implicits with default parameters
If an implicit parameter has a default, then that
default should be taken in case no implicit argument
is found.
Diffstat (limited to 'src/dotty/tools/dotc/typer/Typer.scala')
-rw-r--r-- | src/dotty/tools/dotc/typer/Typer.scala | 30 |
1 files changed, 25 insertions, 5 deletions
diff --git a/src/dotty/tools/dotc/typer/Typer.scala b/src/dotty/tools/dotc/typer/Typer.scala index 6a2ff30fa..b65e3cd42 100644 --- a/src/dotty/tools/dotc/typer/Typer.scala +++ b/src/dotty/tools/dotc/typer/Typer.scala @@ -1435,10 +1435,15 @@ class Typer extends Namer with TypeAssigner with Applications with Implicits wit wtp.paramTypes.foreach(instantiateSelected(_, tvarsToInstantiate)) val constr = ctx.typerState.constraint def addImplicitArgs = { - def implicitArgError(msg: => String): Tree = { - ctx.error(msg, tree.pos.endPos) + val errors = new mutable.ListBuffer[() => String] + def implicitArgError(msg: => String) = { + errors += (() => msg) EmptyTree } + def issueErrors() = { + for (err <- errors) ctx.error(err(), tree.pos.endPos) + tree + } val args = (wtp.paramNames, wtp.paramTypes).zipped map { (pname, formal) => def where = d"parameter $pname of $methodStr" inferImplicit(formal, EmptyTree, tree.pos.endPos) match { @@ -1450,12 +1455,27 @@ class Typer extends Namer with TypeAssigner with Applications with Implicits wit implicitArgError(d"no implicit argument of type $formal found for $where" + failure.postscript) } } - if (args.exists(_.isEmpty)) { + if (errors.nonEmpty) { // If there are several arguments, some arguments might already - // have influenced the context, binfing variables, but later ones + // have influenced the context, binding variables, but later ones // might fail. In that case the constraint needs to be reset. ctx.typerState.constraint = constr - tree + + // If method has default params, fall back to regular application + // where all inferred implicits are passed as named args. + if (tree.symbol.hasDefaultParams) { + val namedArgs = (wtp.paramNames, args).zipped.flatMap { (pname, arg) => + arg match { + case EmptyTree => Nil + case _ => untpd.NamedArg(pname, untpd.TypedSplice(arg)) :: Nil + } + } + tryEither { implicit ctx => + typed(untpd.Apply(untpd.TypedSplice(tree), namedArgs), pt) + } { (_, _) => + issueErrors() + } + } else issueErrors() } else adapt(tpd.Apply(tree, args), pt) } |