Add reflect Symbol.info and ClassInfo #11664
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| trait ClassInfoMethods: | ||
| extension (self: ClassInfo) | ||
| /** The prefix on which parents, decls, and selfType need to be rebased. */ | ||
| def prefix: TypeRepr |
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Is prefix here a different thing from qualifier in TypeRef?
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It is a similar qualification. We have used qualifier in all the cases of the API, I will do the same here to be homogeneous. There is a similar case with NamedType.
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@nicolasstucki Right, although I wonder if it's not too late to name it prefix everywhere instead of qualifier, for consistency with Scala 2 and previous literature
Also fix TypeReprStructure printer for Binder to avoid cycles and remove workaround in TypeLambda. Fixes scala#11657
| extension (self: ClassInfo) | ||
| def qualifier: TypeRepr = self.prefix | ||
| def decls: List[Symbol] = self.decls.toList | ||
| def declaredParents: List[TypeRepr] = self.declaredParents |
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I wouldn't expose declaredParents as it's just a less precise version of parents: https://github.com/lampepfl/dotty/blob/0dbe9705ec6a319af2365de4e00d3f66154fc133/compiler/src/dotty/tools/dotc/core/Types.scala#L4536
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But then we would have to always go to the tree which is the thing we are trying to avoid.
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But then we would have to always go to the tree
No, we should expose Type#parents which doesn't involve trees.
| this += "TypeLambda(" ++= argNames += ", " ++= argBounds += ", _)" | ||
| this += "TypeLambda(" ++= argNames += ", " ++= argBounds += ", " += resType += ")" | ||
| case ClassInfo(prefix, cls, parents, decls, selfInfo) => | ||
| this += "ClassInfo(" += prefix += ", cls/*" += cls.fullName += "*/, " ++= parents += ", decls, " += selfInfo += ")" |
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Is cls added by accident?
| this += "ClassInfo(" += prefix += ", cls/*" += cls.fullName += "*/, " ++= parents += ", decls, " += selfInfo += ")" | |
| this += "ClassInfo(" += prefix += ", /*" += cls.fullName += "*/, " ++= parents += ", decls, " += selfInfo += ")" |
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No, we want to generate something like ClassInfo(X, cls /*...*/, ..., ...). If we remove the cls it would not parse as valid scala code. The comment is there to hint at what is in that parameter but there is no structure to it.
| @@ -3437,6 +3472,9 @@ trait Quotes { self: runtime.QuoteUnpickler & runtime.QuoteMatching => | |||
| trait SymbolMethods { | |||
| extension (self: Symbol) | |||
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| /** TypeRepr of the definitions of this symbol */ | |||
| def info: TypeRepr | |||
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If we expose info on symbols, logically we need to expose Type.asSeenFrom as well to rebase the prefix.
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Maybe add a document here saying
Warning: you may need to perform
asSeenFromin caseSymbol.infocontains parameterized types, such as class type parameter, types depend onthis, etc.For example, if the owner of the current symbol is a class, using the following code to rebase the type:
symbol.info.asSeenFrom(prefix, symbol.owner)
What about a method like symbol.infoAsSeenFrom(prefix)?
| extension (self: ClassInfo) | ||
| def qualifier: TypeRepr = self.prefix | ||
| def decls: List[Symbol] = self.decls.toList | ||
| def declaredParents: List[TypeRepr] = self.declaredParents |
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But then we would have to always go to the tree
No, we should expose Type#parents which doesn't involve trees.
| @@ -1695,6 +1695,8 @@ class QuotesImpl private (using val ctx: Context) extends Quotes, QuoteUnpickler | |||
| dotc.core.Types.decorateTypeApplications(self).appliedTo(targ) | |||
| def appliedTo(targs: List[TypeRepr]): TypeRepr = | |||
| dotc.core.Types.decorateTypeApplications(self).appliedTo(targs) | |||
| def asSeenFrom(pre: TypeRepr, clazz: Symbol): TypeRepr = | |||
| self.asSeenFrom(pre, clazz) | |||
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We already expose memberInfo which calls asSeenFrom, in what situation would you need the raw asSeenFrom?
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If we expose symbol.info, without asSeenFrom, the info cannot be safely used.
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symbol.info is the info of the symbol itself, I don't see what's unsafe about it, and if you want to see the info from some specific prefix you can do prefix.memberType(symbol). Are there situations where you need to use asSeenFrom directly instead?
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symbol.info is the info of the symbol itself, I don't see what's unsafe about it, if you want to see the info from some specific prefix you can do prefix.memberType(symbol). Are there situations where you need to use asSeenFrom directly instead?
The concern is that users use symbol.info without rebasing, resulting in error-prone macros. I see that we already have TypeEpr.memberType, thus we don't need asSeenFrom. However, it is good to add the following doc to Symbol.info:
Warning:
Symbol.infomay contain parameterized types, such as class type parameter, types that depend onthis, etc. The method callprefix.memberType(symbol)can be used to get the concrete type of the symbol relative to a prefix.
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The point of this was to make the API simpler to use, but by using |
Also fix TypeReprStructure printer for Binder to avoid cycles and remove workaround in TypeLambda.
Fixes #11657