internal/lsp/cache: delete checkSnapshotLocked

Now that the entire metadata graph and workspace packages are derived
from metadata, there should be no need to validate coherency.

This results in a small improvement to didChange benchmarking (within
statistical noise).

For golang/go#45686

Change-Id: I32683e025f42d768d62864683e55d4c00146a31c
Reviewed-on: https://go-review.googlesource.com/c/tools/+/340855
TryBot-Result: Gopher Robot <gobot@golang.org>
gopls-CI: kokoro <noreply+kokoro@google.com>
Reviewed-by: Alan Donovan <adonovan@google.com>
Run-TryBot: Robert Findley <rfindley@google.com>

internal/lsp/cache/snapshot.go

@@ -30,7 +30,6 @@ import (
 	"golang.org/x/tools/internal/event"
 	"golang.org/x/tools/internal/gocommand"
 	"golang.org/x/tools/internal/lsp/bug"
-	"golang.org/x/tools/internal/lsp/debug/log"
 	"golang.org/x/tools/internal/lsp/debug/tag"
 	"golang.org/x/tools/internal/lsp/source"
 	"golang.org/x/tools/internal/memoize"
@@ -1638,29 +1637,6 @@ func generationName(v *View, snapshotID uint64) string {
 	return fmt.Sprintf("v%v/%v", v.id, snapshotID)
 }
 
-// checkSnapshotLocked verifies that some invariants are preserved on the
-// snapshot.
-func checkSnapshotLocked(ctx context.Context, s *snapshot) {
-	// Check that every go file for a workspace package is identified as
-	// belonging to that workspace package.
-	for wsID := range s.workspacePackages {
-		if m, ok := s.meta.metadata[wsID]; ok {
-			for _, uri := range m.GoFiles {
-				found := false
-				for _, id := range s.meta.ids[uri] {
-					if id == wsID {
-						found = true
-						break
-					}
-				}
-				if !found {
-					log.Error.Logf(ctx, "workspace package %v not associated with %v", wsID, uri)
-				}
-			}
-		}
-	}
-}
-
 // unappliedChanges is a file source that handles an uncloned snapshot.
 type unappliedChanges struct {
 	originalSnapshot *snapshot
@@ -1684,8 +1660,6 @@ func (s *snapshot) clone(ctx, bgCtx context.Context, changes map[span.URI]*fileC
 	s.mu.Lock()
 	defer s.mu.Unlock()
 
-	checkSnapshotLocked(ctx, s)
-
 	newGen := s.view.session.cache.store.Generation(generationName(s.view, s.id+1))
 	bgCtx, cancel := context.WithCancel(bgCtx)
 	result := &snapshot{