Minor tweaks based on PR feedback

src/Compilers/Core/Portable/Compilation/Compilation.cs

@@ -2508,7 +2508,7 @@ internal void EnsureAnonymousTypeTemplates(CancellationToken cancellationToken)
                         metadataStream, 
                         ilStream, 
                         (nativePdbWriterOpt == null) ? pdbStream : null,
-                        out var metadataSizes);
+                        out MetadataSizes metadataSizes);
 
                     writer.GetMethodTokens(updatedMethods);
 

src/Compilers/Core/Portable/Emit/EditAndContinue/DeltaMetadataWriter.cs

@@ -51,7 +51,7 @@ internal sealed class DeltaMetadataWriter : MetadataWriter
             SymbolChanges changes,
             CancellationToken cancellationToken)
             : base(metadata: MakeTablesBuilder(previousGeneration), 
-                   debugMetadataOpt: (context.Module.EmitOptions.DebugInformationFormat != DebugInformationFormat.Pdb) ? new MetadataBuilder() : null, 
+                   debugMetadataOpt: (context.Module.EmitOptions.DebugInformationFormat == DebugInformationFormat.PortablePdb) ? new MetadataBuilder() : null, 
                    dynamicAnalysisDataWriterOpt: null,
                    context: context,
                    messageProvider: messageProvider,
@@ -62,6 +62,7 @@ internal sealed class DeltaMetadataWriter : MetadataWriter
             Debug.Assert(previousGeneration != null);
             Debug.Assert(encId != default(Guid));
             Debug.Assert(encId != previousGeneration.EncId);
+            Debug.Assert(context.Module.EmitOptions.DebugInformationFormat != DebugInformationFormat.Embedded);
 
             _previousGeneration = previousGeneration;
             _encId = encId;

src/Compilers/Core/Portable/PEWriter/MetadataWriter.cs

@@ -1809,7 +1809,8 @@ public void WriteMetadataAndIL(PdbWriter nativePdbWriterOpt, Stream metadataStre
 
         public void PopulateEncTables(ImmutableArray<int> typeSystemRowCounts)
         {
-            Debug.Assert(typeSystemRowCounts[(int)TableIndex.EncLog] == 0 && typeSystemRowCounts[(int)TableIndex.EncMap] == 0);
+            Debug.Assert(typeSystemRowCounts[(int)TableIndex.EncLog] == 0);
+            Debug.Assert(typeSystemRowCounts[(int)TableIndex.EncMap] == 0);
 
             PopulateEncLogTableRows(typeSystemRowCounts);
             PopulateEncMapTableRows(typeSystemRowCounts);

src/Test/PdbUtilities/Pdb/PdbToXml.cs

@@ -1270,8 +1270,8 @@ private void WriteSequencePoints(ImmutableArray<SymUnmanagedSequencePoint> seque
 
         private unsafe ImmutableArray<MethodDefinitionHandle> BuildMethodTokenMap()
         {
-            if (!(_symReader is ISymUnmanagedReader5 symReader5) ||
-                symReader5.GetPortableDebugMetadata(out byte* metadata, out int size) != 0)
+            if (!(_symReader is ISymUnmanagedReader4 symReader4) ||
+                symReader4.GetPortableDebugMetadata(out byte* metadata, out int size) != 0)
             {
                 return ImmutableArray<MethodDefinitionHandle>.Empty;
             }

src/Test/Utilities/Portable/Compilation/CompilationDifference.cs

@@ -32,17 +32,17 @@ internal sealed class CompilationDifference
         public CompilationDifference(
             ImmutableArray<byte> metadata,
             ImmutableArray<byte> il,
-            ImmutableArray<byte> pdbStream,
+            ImmutableArray<byte> pdb,
             CompilationTestData testData,
             EmitDifferenceResult result,
             ImmutableArray<MethodDefinitionHandle> methodHandles)
         {
-            this.MetadataDelta = metadata;
-            this.ILDelta = il;
-            this.PdbDelta = pdbStream;
-            this.TestData = testData;
-            this.EmitResult = result;
-            this.UpdatedMethods = methodHandles;
+            MetadataDelta = metadata;
+            ILDelta = il;
+            PdbDelta = pdb;
+            TestData = testData;
+            EmitResult = result;
+            UpdatedMethods = methodHandles;
         }
 
         public EmitBaseline NextGeneration

src/Test/Utilities/Portable/Pdb/PdbValidation.cs

@@ -146,14 +146,13 @@ public static class PdbValidation
             Assert.True(actualIsPortable);
 
             // SymWriter doesn't create empty scopes. When the C# compiler uses forwarding CDI instead of a NamespaceScope
-            // the scope is actually not empty - it logically contains the imports. Portable PDB does not used forwarding and thus
+            // the scope is actually not empty - it logically contains the imports. Portable PDB does not use forwarding and thus
             // creates the scope. When generating PDB XML for testing the Portable DiaSymReader returns empty namespaces.
             RemoveEmptyScopes(actualPdb);
 
             // if the actual format is portable and the expected is not, remove native-only artifacts:
             RemoveNonPortablePdb(expectedPdb);
 
-            // TODO: remove
             RemoveEmptySequencePoints(expectedPdb);
 
             // remove scopes that only contained non-portable elements (namespace scopes)