// only comparable types are meant; in all other cases comparable is false.
type _TypeSet struct {
	methods    []*Func  // all methods of the interface; sorted by unique ID
	terms      termlist // type terms of the type set
	comparable bool     // invariant: !comparable || terms.isAll()
}

// IsEmpty reports whether type set s is the empty set.

// at fs into a single document.
// The blocks of the documents are concatenated in lexicographic order by filename.
// Heading with no content are removed.
// The link keys must be unique, and are combined into a single map.
//
// Files in the "minor changes" directory (the unique directory matching the glob
// "*stdlib/*minor") are named after the package to which they refer, and will have

}

// ImportMissingSumError is reported in readonly mode when we need to check
// if a module contains a package, but we don't have a sum for its .zip file.
// We might need sums for multiple modules to verify the package is unique.
//
// TODO(#43653): consolidate multiple errors of this type into a single error
// that suggests a 'go get' command for root packages that transitively import

// The default is regular Go syntax (fmtGo).
// fmtDebug is like fmtGo but for debugging dumps and prints the type kind too.
// fmtTypeID and fmtTypeIDName are for generating various unique representations
// of types used in hashes, the linker, and function/method instantiations.
type fmtMode int

const (
	fmtGo fmtMode = iota
	fmtDebug
	fmtTypeID
	fmtTypeIDName
)

// Sym

}

func NodNil() ir.Node {
	return ir.NewNilExpr(base.Pos, types.Types[types.TNIL])
}

// AddImplicitDots finds missing fields in obj.field that
// will give the shortest unique addressing and
// modifies the tree with missing field names.
func AddImplicitDots(n *ir.SelectorExpr) *ir.SelectorExpr {
	n.X = typecheck(n.X, ctxType|ctxExpr)
	t := n.X.Type()
	if t == nil {
		return n
	}

// Fun takes the name of an entry bloc and a series of Bloc calls, and
// returns a fun containing the composed Func. entry must be a name
// supplied to one of the Bloc functions. Each of the bloc names and
// valu names should be unique across the Fun.
func (c *Conf) Fun(entry string, blocs ...bloc) fun {
	// TODO: Either mark some SSA tests as t.Parallel,
	// or set up a shared Cache and Reset it between tests.
	// But not both.

	// funcLitGen, rangeLitGen and goDeferGen track how many closures have been
	// created in this function for function literals, range-over-func loops,
	// and go/defer wrappers, respectively. Used by closureName for creating
	// unique function names.
	// Tracking goDeferGen separately avoids wrappers throwing off
	// function literal numbering (e.g., runtime/trace_test.TestTraceSymbolize.func11).
	funcLitGen  int32
	rangeLitGen int32

}

// contentID returns the content ID half of a build ID.
func contentID(buildID string) string {
	return buildID[strings.LastIndex(buildID, buildIDSeparator)+1:]
}

// toolID returns the unique ID to use for the current copy of the
// named tool (asm, compile, cover, link).
//
// It is important that if the tool changes (for example a compiler bug is fixed

	// otherwise-unconstrained package that has available upgrades.
	candidates   []pathSet
	candidatesMu sync.Mutex

	// pathSeen ensures that only one pathSet is added to the query per
	// unique path.
	pathSeen sync.Map

	// resolved contains the set of modules whose versions have been determined by
	// this query, in the order in which they were determined.
	//

				continue
			}
			headers = append(headers, p)
		}
	}
	return headers
}

// HeaderForFileOffset attempts to identify a unique program header that
// includes the given file offset. It returns an error if it cannot identify a
// unique header.
func HeaderForFileOffset(headers []*elf.ProgHeader, fileOffset uint64) (*elf.ProgHeader, error) {
	var ph *elf.ProgHeader
	for _, h := range headers {