diff options
Diffstat (limited to 'src/compiler/scala/tools/nsc/typechecker/Typers.scala')
| -rw-r--r-- | src/compiler/scala/tools/nsc/typechecker/Typers.scala | 28 |
1 files changed, 14 insertions, 14 deletions
diff --git a/src/compiler/scala/tools/nsc/typechecker/Typers.scala b/src/compiler/scala/tools/nsc/typechecker/Typers.scala index f581eab00f..4f006fe9a9 100644 --- a/src/compiler/scala/tools/nsc/typechecker/Typers.scala +++ b/src/compiler/scala/tools/nsc/typechecker/Typers.scala @@ -2726,7 +2726,7 @@ trait Typers extends Adaptations with Tags with TypersTracking with PatternTyper * * ``` * new S { - * <static> def apply$body(p1: T1, ..., pN: TN): T = body + * def apply$body(p1: T1, ..., pN: TN): T = body * def apply(p1: T1', ..., pN: TN'): T' = apply$body(p1,..., pN) * } * ``` @@ -2737,27 +2737,28 @@ trait Typers extends Adaptations with Tags with TypersTracking with PatternTyper * The types T1' ... TN' and T' are derived from the method signature of the sam method, * as seen from the fully defined `samClassTpFullyDefined`. * - * The function's body is put in a static method in the class definition to enforce scoping. + * The function's body is put in a (static) method in the class definition to enforce scoping. * S's members should not be in scope in `body`. (Putting it in the block outside the class runs into implementation problems described below) * * The restriction on implicit arguments (neither S's constructor, nor sam may take an implicit argument list), - * is largely to keep the implementation of type inference (the computation of `samClassTpFullyDefined`) simple. + * is to keep the implementation of type inference (the computation of `samClassTpFullyDefined`) simple. + * + * Impl notes: + * - `fun` has a FunctionType, but the expected type `pt` is some SAM type -- let's remedy that + * - `fun` is fully attributed, so we'll have to wrangle some symbols into shape (owner change, vparam syms) + * - after experimentation, it works best to type check function literals fully first and then adapt to a sam type, + * as opposed to a sam-specific code paths earlier on in type checking (in typedFunction). + * For one, we want to emit the same bytecode regardless of whether the expected + * function type is a built-in FunctionN or some SAM type * */ def adaptToSAM(sam: Symbol, fun: Function, pt: Type, mode: Mode): Tree = { - // `fun` has a FunctionType, but the expected type `pt` is some SAM type -- let's remedy that - // `fun` is fully attributed, so we'll have to wrangle some symbols into shape (owner change, vparam syms) - // I tried very hard to leave `fun` untyped and rework everything into the right shape and type check once, - // but couldn't make it work due to retyping that happens down the line - // (implicit conversion retries/retypechecking, CBN transform, super call arg context nesting weirdness) - - def funTpMatchesExpected(pt: Type): Boolean = isFullyDefined(pt) && { - // what's the signature of the method that we should actually be overriding? + def fullyDefinedMeetsExpectedFunTp(pt: Type): Boolean = isFullyDefined(pt) && { val samMethType = pt memberInfo sam fun.tpe <:< functionType(samMethType.paramTypes, samMethType.resultType) } - if (funTpMatchesExpected(pt)) fun.setType(pt) + if (fullyDefinedMeetsExpectedFunTp(pt)) fun.setType(pt) else try { val samClassSym = pt.typeSymbol @@ -2786,9 +2787,8 @@ trait Typers extends Adaptations with Tags with TypersTracking with PatternTyper debuglog(s"sam infer: $pt --> ${appliedType(samTyCon, targs)} by ${fun.tpe} <:< $samInfoWithTVars --> $targs for $tparams") - // a fully defined samClassTp val ptFullyDefined = appliedType(samTyCon, targs) - if (funTpMatchesExpected(ptFullyDefined)) { + if (ptFullyDefined <:< pt && fullyDefinedMeetsExpectedFunTp(ptFullyDefined)) { debuglog(s"sam fully defined expected type: $ptFullyDefined from $pt for ${fun.tpe}") fun.setType(ptFullyDefined) } else { |