diff --git a/gopls/internal/cache/parsego/file.go b/gopls/internal/cache/parsego/file.go
index 3e13d5b2c43..b03929e6c86 100644
--- a/gopls/internal/cache/parsego/file.go
+++ b/gopls/internal/cache/parsego/file.go
@@ -41,10 +41,12 @@ type File struct {
 	ParseErr scanner.ErrorList
 }
 
+func (pgf File) String() string { return string(pgf.URI) }
+
 // Fixed reports whether p was "Fixed", meaning that its source or positions
 // may not correlate with the original file.
-func (p File) Fixed() bool {
-	return p.fixedSrc || p.fixedAST
+func (pgf File) Fixed() bool {
+	return pgf.fixedSrc || pgf.fixedAST
 }
 
 // -- go/token domain convenience helpers --
diff --git a/gopls/internal/golang/call_hierarchy.go b/gopls/internal/golang/call_hierarchy.go
index 5331e6eaabf..4971208e79d 100644
--- a/gopls/internal/golang/call_hierarchy.go
+++ b/gopls/internal/golang/call_hierarchy.go
@@ -201,13 +201,8 @@ func OutgoingCalls(ctx context.Context, snapshot *cache.Snapshot, fh file.Handle
 		return nil, nil
 	}
 
-	// Skip builtins.
-	if obj.Pkg() == nil {
-		return nil, nil
-	}
-
-	if !obj.Pos().IsValid() {
-		return nil, bug.Errorf("internal error: object %s.%s missing position", obj.Pkg().Path(), obj.Name())
+	if isBuiltin(obj) {
+		return nil, nil // built-ins have no position
 	}
 
 	declFile := pkg.FileSet().File(obj.Pos())
@@ -271,10 +266,8 @@ func OutgoingCalls(ctx context.Context, snapshot *cache.Snapshot, fh file.Handle
 		if obj == nil {
 			continue
 		}
-
-		// ignore calls to builtin functions
-		if obj.Pkg() == nil {
-			continue
+		if isBuiltin(obj) {
+			continue // built-ins have no position
 		}
 
 		outgoingCall, ok := outgoingCalls[obj.Pos()]
diff --git a/gopls/internal/golang/definition.go b/gopls/internal/golang/definition.go
index d2a61e17f13..6184e292928 100644
--- a/gopls/internal/golang/definition.go
+++ b/gopls/internal/golang/definition.go
@@ -87,8 +87,8 @@ func Definition(ctx context.Context, snapshot *cache.Snapshot, fh file.Handle, p
 		return nil, nil
 	}
 
-	// Handle objects with no position: builtin, unsafe.
-	if !obj.Pos().IsValid() {
+	// Built-ins have no position.
+	if isBuiltin(obj) {
 		return builtinDefinition(ctx, snapshot, obj)
 	}
 
diff --git a/gopls/internal/golang/hover.go b/gopls/internal/golang/hover.go
index 5c9bae36fce..1eb32d9e4b7 100644
--- a/gopls/internal/golang/hover.go
+++ b/gopls/internal/golang/hover.go
@@ -169,12 +169,14 @@ func hover(ctx context.Context, snapshot *cache.Snapshot, fh file.Handle, pp pro
 
 	// Handle hovering over a doc link
 	if obj, rng, _ := parseDocLink(pkg, pgf, pos); obj != nil {
-		hoverRange = &rng
-		// Handle builtins, which don't have a package or position.
-		if !obj.Pos().IsValid() {
+		// Built-ins have no position.
+		if isBuiltin(obj) {
 			h, err := hoverBuiltin(ctx, snapshot, obj)
-			return *hoverRange, h, err
+			return rng, h, err
 		}
+
+		// Find position in declaring file.
+		hoverRange = &rng
 		objURI := safetoken.StartPosition(pkg.FileSet(), obj.Pos())
 		pkg, pgf, err = NarrowestPackageForFile(ctx, snapshot, protocol.URIFromPath(objURI.Filename))
 		if err != nil {
@@ -240,8 +242,8 @@ func hover(ctx context.Context, snapshot *cache.Snapshot, fh file.Handle, pp pro
 		}, nil
 	}
 
-	// Handle builtins, which don't have a package or position.
-	if !obj.Pos().IsValid() {
+	if isBuiltin(obj) {
+		// Built-ins have no position.
 		h, err := hoverBuiltin(ctx, snapshot, obj)
 		return *hoverRange, h, err
 	}
diff --git a/gopls/internal/golang/references.go b/gopls/internal/golang/references.go
index e5d9f2a4581..954748fbc36 100644
--- a/gopls/internal/golang/references.go
+++ b/gopls/internal/golang/references.go
@@ -252,15 +252,9 @@ func ordinaryReferences(ctx context.Context, snapshot *cache.Snapshot, uri proto
 	}
 
 	// nil, error, error.Error, iota, or other built-in?
-	if obj.Pkg() == nil {
+	if isBuiltin(obj) {
 		return nil, fmt.Errorf("references to builtin %q are not supported", obj.Name())
 	}
-	if !obj.Pos().IsValid() {
-		if obj.Pkg().Path() != "unsafe" {
-			bug.Reportf("references: object %v has no position", obj)
-		}
-		return nil, fmt.Errorf("references to unsafe.%s are not supported", obj.Name())
-	}
 
 	// Find metadata of all packages containing the object's defining file.
 	// This may include the query pkg, and possibly other variants.
diff --git a/gopls/internal/golang/signature_help.go b/gopls/internal/golang/signature_help.go
index 488387f0a18..a91be296cbd 100644
--- a/gopls/internal/golang/signature_help.go
+++ b/gopls/internal/golang/signature_help.go
@@ -99,9 +99,7 @@ FindCall:
 	case *ast.SelectorExpr:
 		obj = info.ObjectOf(t.Sel)
 	}
-
-	// Call to built-in?
-	if obj != nil && !obj.Pos().IsValid() {
+	if obj != nil && isBuiltin(obj) {
 		// function?
 		if obj, ok := obj.(*types.Builtin); ok {
 			return builtinSignature(ctx, snapshot, callExpr, obj.Name(), pos)
diff --git a/gopls/internal/golang/type_definition.go b/gopls/internal/golang/type_definition.go
index 306852cdcaf..a396793e48a 100644
--- a/gopls/internal/golang/type_definition.go
+++ b/gopls/internal/golang/type_definition.go
@@ -12,7 +12,6 @@ import (
 	"golang.org/x/tools/gopls/internal/cache"
 	"golang.org/x/tools/gopls/internal/file"
 	"golang.org/x/tools/gopls/internal/protocol"
-	"golang.org/x/tools/gopls/internal/util/bug"
 	"golang.org/x/tools/internal/event"
 )
 
@@ -42,13 +41,8 @@ func TypeDefinition(ctx context.Context, snapshot *cache.Snapshot, fh file.Handl
 	if tname == nil {
 		return nil, fmt.Errorf("no type definition for %s", obj.Name())
 	}
-
-	if !tname.Pos().IsValid() {
-		// The only defined types with no position are error and comparable.
-		if tname.Name() != "error" && tname.Name() != "comparable" {
-			bug.Reportf("unexpected type name with no position: %s", tname)
-		}
-		return nil, nil
+	if isBuiltin(tname) {
+		return nil, nil // built-ins (error, comparable) have no position
 	}
 
 	loc, err := mapPosition(ctx, pkg.FileSet(), snapshot, tname.Pos(), tname.Pos()+token.Pos(len(tname.Name())))
diff --git a/gopls/internal/golang/types_format.go b/gopls/internal/golang/types_format.go
index ebdf46f3e74..51584bcb013 100644
--- a/gopls/internal/golang/types_format.go
+++ b/gopls/internal/golang/types_format.go
@@ -283,7 +283,7 @@ func FormatVarType(ctx context.Context, snapshot *cache.Snapshot, srcpkg *cache.
 		return types.TypeString(obj.Type(), qf), nil
 	}
 
-	if obj.Pkg() == nil || !obj.Pos().IsValid() {
+	if isBuiltin(obj) {
 		// This is defensive, though it is extremely unlikely we'll ever have a
 		// builtin var.
 		return types.TypeString(obj.Type(), qf), nil
diff --git a/gopls/internal/golang/util.go b/gopls/internal/golang/util.go
index 903fdd97936..3279dc8fc2e 100644
--- a/gopls/internal/golang/util.go
+++ b/gopls/internal/golang/util.go
@@ -350,3 +350,7 @@ func embeddedIdent(x ast.Expr) *ast.Ident {
 type ImporterFunc func(path string) (*types.Package, error)
 
 func (f ImporterFunc) Import(path string) (*types.Package, error) { return f(path) }
+
+// isBuiltin reports whether obj is a built-in symbol (e.g. append, iota, error.Error, unsafe.Slice).
+// All other symbols have a valid position and a valid package.
+func isBuiltin(obj types.Object) bool { return !obj.Pos().IsValid() }
diff --git a/gopls/internal/test/marker/testdata/callhierarchy/issue66923.txt b/gopls/internal/test/marker/testdata/callhierarchy/issue66923.txt
new file mode 100644
index 00000000000..4a5e59f9f9a
--- /dev/null
+++ b/gopls/internal/test/marker/testdata/callhierarchy/issue66923.txt
@@ -0,0 +1,15 @@
+Regression test for a crash (#66923) in outgoing calls
+to a built-in function (unsafe.Slice).
+
+-- go.mod --
+module example.com
+go 1.17
+
+-- a/a.go --
+package a
+
+import "unsafe"
+
+func A() []int {			 //@ loc(A, "A")
+	return unsafe.Slice(new(int), 1) //@ outgoingcalls(A)
+}