[automated] Merge branch 'main-vs-deps' => 'release/dev17.15' (#77761)

I detected changes in the main-vs-deps branch which have not been merged
yet to release/dev17.15. I'm a robot and am configured to help you
automatically keep release/dev17.15 up to date, so I've opened this PR.

This PR merges commits made on main-vs-deps by the following committers:

* dotnet-policy-service[bot]
* CyrusNajmabadi

## Instructions for merging from UI

This PR will not be auto-merged. When pull request checks pass, complete
this PR by creating a merge commit, *not* a squash or rebase commit.

<img alt="merge button instructions"
src="https://i.imgur.com/GepcNJV.png" width="300" />

If this repo does not allow creating merge commits from the GitHub UI,
use command line instructions.

## Instructions for merging via command line

Run these commands to merge this pull request from the command line.

``` sh
git fetch
git checkout main-vs-deps
git pull --ff-only
git checkout release/dev17.15
git pull --ff-only
git merge --no-ff main-vs-deps

# If there are merge conflicts, resolve them and then run git merge --continue to complete the merge
# Pushing the changes to the PR branch will re-trigger PR validation.
git push https://github.com/dotnet/roslyn HEAD:merge/main-vs-deps-to-release/dev17.15
```

<details>
<summary>or if you are using SSH</summary>

```
git push git@github.com:dotnet/roslyn HEAD:merge/main-vs-deps-to-release/dev17.15
```

</details>


After PR checks are complete push the branch
```
git push
```

## Instructions for resolving conflicts

:warning: If there are merge conflicts, you will need to resolve them
manually before merging. You can do this [using GitHub][resolve-github]
or using the [command line][resolve-cli].

[resolve-github]:
https://help.github.com/articles/resolving-a-merge-conflict-on-github/
[resolve-cli]:
https://help.github.com/articles/resolving-a-merge-conflict-using-the-command-line/

## Instructions for updating this pull request

Contributors to this repo have permission update this pull request by
pushing to the branch 'merge/main-vs-deps-to-release/dev17.15'. This can
be done to resolve conflicts or make other changes to this pull request
before it is merged.
The provided examples assume that the remote is named 'origin'. If you
have a different remote name, please replace 'origin' with the name of
your remote.

```
git fetch
git checkout -b merge/main-vs-deps-to-release/dev17.15 origin/release/dev17.15
git pull https://github.com/dotnet/roslyn merge/main-vs-deps-to-release/dev17.15
(make changes)
git commit -m "Updated PR with my changes"
git push https://github.com/dotnet/roslyn HEAD:merge/main-vs-deps-to-release/dev17.15
```

<details>
    <summary>or if you are using SSH</summary>

```
git fetch
git checkout -b merge/main-vs-deps-to-release/dev17.15 origin/release/dev17.15
git pull git@github.com:dotnet/roslyn merge/main-vs-deps-to-release/dev17.15
(make changes)
git commit -m "Updated PR with my changes"
git push git@github.com:dotnet/roslyn HEAD:merge/main-vs-deps-to-release/dev17.15
```

</details>

Contact .NET Core Engineering (dotnet/dnceng) if you have questions or
issues.
Also, if this PR was generated incorrectly, help us fix it. See
https://github.com/dotnet/arcade/blob/main/.github/workflows/scripts/inter-branch-merge.ps1.

Author: dotnet-policy-service[bot]

src/Workspaces/Core/Portable/Workspace/Solution/SolutionCompilationState.RegularCompilationTracker.cs

@@ -118,11 +118,14 @@ public bool ContainsAssemblyOrModuleOrDynamic(
                 return finalState.RootedSymbolSet.ContainsAssemblyOrModuleOrDynamic(symbol, primary, out compilation, out referencedThrough);
             }
 
+            ICompilationTracker ICompilationTracker.Fork(ProjectState newProjectState, TranslationAction? translate)
+                => Fork(newProjectState, translate);
+
             /// <summary>
             /// Creates a new instance of the compilation info, retaining any already built
             /// compilation state as the now 'old' state
             /// </summary>
-            public ICompilationTracker Fork(
+            public RegularCompilationTracker Fork(
                 ProjectState newProjectState,
                 TranslationAction? translate)
             {
@@ -680,7 +683,10 @@ private async Task<bool> HasSuccessfullyLoadedSlowAsync(
                 return finalState.HasSuccessfullyLoaded;
             }
 
-            public ICompilationTracker WithCreateCreationPolicy(bool forceRegeneration)
+            ICompilationTracker ICompilationTracker.WithCreateCreationPolicy(bool forceRegeneration)
+                => WithCreateCreationPolicy(forceRegeneration);
+
+            public RegularCompilationTracker WithCreateCreationPolicy(bool forceRegeneration)
             {
                 var state = this.ReadState();
 
@@ -736,7 +742,10 @@ public ICompilationTracker WithCreateCreationPolicy(bool forceRegeneration)
                     skeletonReferenceCacheToClone: _skeletonReferenceCache);
             }
 
-            public ICompilationTracker WithDoNotCreateCreationPolicy()
+            ICompilationTracker ICompilationTracker.WithDoNotCreateCreationPolicy()
+                => WithDoNotCreateCreationPolicy();
+
+            public RegularCompilationTracker WithDoNotCreateCreationPolicy()
             {
                 var state = this.ReadState();
 

src/Workspaces/Core/Portable/Workspace/Solution/SolutionCompilationState.WithFrozenSourceGeneratedDocumentsCompilationTracker.cs

@@ -35,7 +35,7 @@ private sealed class WithFrozenSourceGeneratedDocumentsCompilationTracker : ICom
         [DisallowNull]
         private Compilation? _compilationWithReplacements;
 
-        public ICompilationTracker UnderlyingTracker { get; }
+        public RegularCompilationTracker UnderlyingTracker { get; }
         public ProjectState ProjectState => UnderlyingTracker.ProjectState;
 
         public GeneratorDriver? GeneratorDriver => UnderlyingTracker.GeneratorDriver;
@@ -46,7 +46,7 @@ private sealed class WithFrozenSourceGeneratedDocumentsCompilationTracker : ICom
         private SkeletonReferenceCache _skeletonReferenceCache;
 
         public WithFrozenSourceGeneratedDocumentsCompilationTracker(
-            ICompilationTracker underlyingTracker,
+            RegularCompilationTracker underlyingTracker,
             TextDocumentStates<SourceGeneratedDocumentState> replacementDocumentStates)
         {
             this.UnderlyingTracker = underlyingTracker;

src/Workspaces/Core/Portable/Workspace/Solution/SolutionCompilationState.cs

@@ -1385,7 +1385,12 @@ public SolutionCompilationState WithFrozenSourceGeneratedDocuments(
                         existingTracker = CreateCompilationTracker(projectId, arg.SolutionState);
                     }
 
-                    trackerMap[projectId] = new WithFrozenSourceGeneratedDocumentsCompilationTracker(existingTracker, new(documentStatesForProject));
+                    // We should never be wrapping a WithFrozenSourceGeneratedDocumentsCompilationTracker with another
+                    // WithFrozenSourceGeneratedDocumentsCompilationTracker.  If we do, that's a straight bug that
+                    // should fail immediately.  So blind casting is here is appropriate.
+                    var regularCompilationTracker = (RegularCompilationTracker)existingTracker;
+                    trackerMap[projectId] = new WithFrozenSourceGeneratedDocumentsCompilationTracker(
+                        regularCompilationTracker, new(documentStatesForProject));
                 }
             },
             (documentStatesByProjectId, this.SolutionState),