cmd/cue/cmd: fix bug in resolving builtin package shorthandsRegression resulted in supporting only top-levelbuiltin packages.Fixes#999Change-Id: Ia22ed7435e59cf788e0664cff222eae1887c3b0dReviewed-on:https://cue-review.googlesource.com/c/cue/+/9902Reviewed-by: CUE cueckoo <cueckoo@gmail.com>Reviewed-by: Paul Jolly <paul@myitcv.org.uk>

cue/cmd/cue: fix regression for -H flagInstance iterator accidentally would include instance twicein some cases, which caused it to be unified into a newanonoymous package for which hidden fields would notbe shown.Also adds an optimization in Unify to return one ofthe arguments if they are identical, instead of unifying.The setting the variable instead of returning makes usinga debugger easier.Change-Id: I311c0d2dcb50d277a47eaaae352e5fb467935ebaReviewed-on:https://cue-review.googlesource.com/c/cue/+/9844Reviewed-by: CUE cueckoo <cueckoo@gmail.com>Reviewed-by: Paul Jolly <paul@myitcv.org.uk>

cmd/cue/cmd: better checks for incorrect flagsFixes#969Change-Id: I1628c5158c996830576dc65e4b6fc667e0009b46Reviewed-on:https://cue-review.googlesource.com/c/cue/+/9821Reviewed-by: CUE cueckoo <cueckoo@gmail.com>Reviewed-by: Paul Jolly <paul@myitcv.org.uk>

doc/ref/spec.md: remove "dead code"This removed section is outdated and incorrect.The relevant matter is discussed in the sections below.Fixes#939Change-Id: Id8bff5b790132177c95617621e87cfc613c28590Reviewed-on:https://cue-review.googlesource.com/c/cue/+/9701Reviewed-by: Paul Jolly <paul@myitcv.org.uk>

cue: clean up FormatMakes format more intuitive and gives bonus featuresto mitigate any pain this causes for backwardsincompatibility.Fixes#882Change-Id: I6390f95c4e7b27b9e0a195bd936f6aae55aadf27Reviewed-on:https://cue-review.googlesource.com/c/cue/+/9487Reviewed-by: CUE cueckoo <cueckoo@gmail.com>Reviewed-by: Marcel van Lohuizen <mpvl@golang.org>

cmd/cue/cmd: hook up protobuf encodings typesCloses#606Change-Id: I712ed6f9fc37d53b633a44ed87e4c71c1e018b0fReviewed-on:https://cue-review.googlesource.com/c/cue/+/9372Reviewed-by: CUE cueckoo <cueckoo@gmail.com>Reviewed-by: Marcel van Lohuizen <mpvl@golang.org>

internal/core/export: fix decl export printing and extractionFixes#894A few related fixes:- Extract from all evaluated structs, not just unevaluatedconjuncts, which results in dropping merged values.(Note that unlike with fields attributes, the the declarationattributes are value-bound, and thus need to be included.)- Decl attrs were not always printed in export. This has nowbeen fixed.- Changed the (internal) API to accept a Vertex, insteadof a list of conjuncts, which is a better abstraction.Change-Id: Id598fefa88aff88aefd126fb80f1637b3f50c7fbReviewed-on:https://cue-review.googlesource.com/c/cue/+/9382Reviewed-by: CUE cueckoo <cueckoo@gmail.com>Reviewed-by: Paul Jolly <paul@myitcv.org.uk>Reviewed-by: Marcel van Lohuizen <mpvl@golang.org>

cue: deprecate Value.FieldByNameCan be replaced by LookupPath.Also- make Def behave like LookupDef- update some other deprecation comments- copy over testsChange-Id: If7fa60fda28c9fea1b5328a41d79f52fafde394bReviewed-on:https://cue-review.googlesource.com/c/cue/+/9349Reviewed-by: CUE cueckoo <cueckoo@gmail.com>Reviewed-by: Paul Jolly <paul@myitcv.org.uk>

cmd/cue/cmd: load import dependencies of tool filesFixes#869Fixes#871Change-Id: I7c439d298d819bfc20c33f2e028a0216a57c4307Reviewed-on:https://cue-review.googlesource.com/c/cue/+/9303Reviewed-by: CUE cueckoo <cueckoo@gmail.com>Reviewed-by: Paul Jolly <paul@myitcv.org.uk>

tools/trim: optional fields should not remove non-optionalThe solution is rather brute-force, we need to find somethingmore fine-grained eventually. But for now this avoids anerroneous removal.Fixing this will be easier when optional fields are representedas normal fields with an optional flag, as they were in v0.2.Fixes#855Change-Id: I65829858b1856fcd09aa121f1e1c53fd49864c87Reviewed-on:https://cue-review.googlesource.com/c/cue/+/9221Reviewed-by: CUE cueckoo <cueckoo@gmail.com>Reviewed-by: Marcel van Lohuizen <mpvl@golang.org>