Fix up merge

src/Compilers/CSharp/Portable/Binder/Binder_Patterns.cs

@@ -161,7 +161,7 @@ private BoundPattern BindDiscardPattern(DiscardPatternSyntax node, TypeSymbol in
                 hasErrors = true;
             }
 
-            if (convertedExpression.Type == null && constantValueOpt != ConstantValue.Null)
+            if (convertedExpression.Type is null && constantValueOpt != ConstantValue.Null)
             {
                 Debug.Assert(hasErrors);
                 convertedExpression = new BoundConversion(
@@ -812,7 +812,7 @@ private BoundPattern BindVarPattern(VarPatternSyntax node, TypeSymbol inputType,
             }
 
             TypeSymbol declType = inputType;
-            Symbol foundSymbol = BindTypeOrAliasOrKeyword(node.VarKeyword, node, diagnostics, out bool isVar);
+            Symbol foundSymbol = BindTypeOrAliasOrKeyword(node.VarKeyword, node, diagnostics, out bool isVar).NamespaceOrTypeSymbol;
             if (!isVar)
             {
                 // Give an error if there is a bindable type "var" in scope

src/Compilers/CSharp/Portable/Binder/Binder_Symbols.cs

@@ -149,7 +149,7 @@ private NamespaceOrTypeOrAliasSymbolWithAnnotations BindTypeOrAliasOrKeyword(Ide
             return BindTypeOrAliasOrKeyword(((IdentifierNameSyntax)syntax).Identifier, syntax, diagnostics, out isKeyword);
         }
 
-        private Symbol BindTypeOrAliasOrKeyword(SyntaxToken identifier, SyntaxNode syntax, DiagnosticBag diagnostics, out bool isKeyword)
+        private NamespaceOrTypeOrAliasSymbolWithAnnotations BindTypeOrAliasOrKeyword(SyntaxToken identifier, SyntaxNode syntax, DiagnosticBag diagnostics, out bool isKeyword)
         {
             // Keywords can only be IdentifierNameSyntax
             var identifierValueText = identifier.ValueText;
@@ -246,7 +246,7 @@ private Symbol BindTypeOrAliasOrKeyword(SyntaxToken identifier, SyntaxNode synta
 
             lookupResult.Free();
 
-            return NamespaceOrTypeOrAliasSymbolWithAnnotations.CreateUnannotated(IsNullableEnabled(syntax.Identifier), symbol);
+            return NamespaceOrTypeOrAliasSymbolWithAnnotations.CreateUnannotated(IsNullableEnabled(identifier), symbol);
         }
 
         // Binds the given expression syntax as Type.

src/Compilers/CSharp/Portable/Binder/DecisionDagBuilder.cs

@@ -345,7 +345,7 @@ private DecisionDagBuilder(CSharpCompilation compilation, LabelSymbol defaultLab
             BoundExpression variableAccess = declaration.VariableAccess;
             if (variableAccess != null)
             {
-                Debug.Assert(variableAccess.Type == input.Type);
+                Debug.Assert(variableAccess.Type.Equals(input.Type, TypeCompareKind.AllIgnoreOptions));
                 bindings.Add(new BoundPatternBinding(variableAccess, input));
             }
             else
@@ -376,7 +376,7 @@ private DecisionDagBuilder(CSharpCompilation compilation, LabelSymbol defaultLab
             ArrayBuilder<BoundDagTest> tests)
         {
             MakeCheckNotNull(input, syntax, tests);
-            if (input.Type != type)
+            if (!input.Type.Equals(type, TypeCompareKind.AllIgnoreOptions))
             {
                 TypeSymbol inputType = input.Type.StrippedType(); // since a null check has already been done
                 HashSet<DiagnosticInfo> useSiteDiagnostics = null;
@@ -437,7 +437,7 @@ private static void Assert(bool condition, string message = null)
             ArrayBuilder<BoundDagTest> tests,
             ArrayBuilder<BoundPatternBinding> bindings)
         {
-            Debug.Assert(input.Type.IsErrorType() || recursive.InputType.IsErrorType() || input.Type == recursive.InputType);
+            Debug.Assert(input.Type.IsErrorType() || recursive.InputType.IsErrorType() || input.Type.Equals(recursive.InputType, TypeCompareKind.AllIgnoreOptions));
             var inputType = recursive.DeclaredType?.Type ?? input.Type.StrippedType();
             input = MakeConvertToType(input, recursive.Syntax, inputType, tests);
 
@@ -1259,7 +1259,7 @@ private static bool SameTest(BoundDagTest x, BoundDagTest y)
                 switch (x.Kind)
                 {
                     case BoundKind.DagTypeTest:
-                        return ((BoundDagTypeTest)x).Type == ((BoundDagTypeTest)y).Type;
+                        return ((BoundDagTypeTest)x).Type.Equals(((BoundDagTypeTest)y).Type, TypeCompareKind.AllIgnoreOptions);
 
                     case BoundKind.DagValueTest:
                         return ((BoundDagValueTest)x).Value == ((BoundDagValueTest)y).Value;

src/Compilers/CSharp/Portable/Binder/SwitchExpressionBinder.cs

@@ -123,7 +123,7 @@ private TypeSymbol InferResultType(ImmutableArray<BoundSwitchExpressionArm> swit
             foreach (var @case in switchCases)
             {
                 var type = @case.Value.Type;
-                if (type != null && seenTypes.Add(type))
+                if (!(type is null) && seenTypes.Add(type))
                 {
                     typesInOrder.Add(type);
                 }
@@ -132,7 +132,7 @@ private TypeSymbol InferResultType(ImmutableArray<BoundSwitchExpressionArm> swit
             HashSet<DiagnosticInfo> useSiteDiagnostics = null;
             var commonType = BestTypeInferrer.GetBestType(typesInOrder, Conversions, out _, ref useSiteDiagnostics);
             diagnostics.Add(SwitchExpressionSyntax, useSiteDiagnostics);
-            if (commonType == null)
+            if (commonType is null)
             {
                 diagnostics.Add(ErrorCode.ERR_SwitchExpressionNoBestType, SwitchExpressionSyntax.Location);
                 commonType = CreateErrorType();

src/Compilers/CSharp/Portable/BoundTree/BoundDagTemp.cs

@@ -17,7 +17,7 @@ partial class BoundDagTemp
         public override bool Equals(object obj) => obj is BoundDagTemp other && this.Equals(other);
         public bool Equals(BoundDagTemp other)
         {
-            return other != (object)null && this.Type == other.Type && object.Equals(this.Source, other.Source) && this.Index == other.Index;
+            return other != (object)null && this.Type.Equals(other.Type, TypeCompareKind.AllIgnoreOptions) && object.Equals(this.Source, other.Source) && this.Index == other.Index;
         }
         public override int GetHashCode()
         {

src/Compilers/CSharp/Portable/BoundTree/BoundNode_Source.cs

@@ -292,7 +292,7 @@ void appendSourceCore(BoundNode node, int indent, Dictionary<SynthesizedLocal, i
                         }
                     case BoundSwitchLabel label:
                         {
-                            appendSource(label.ExpressionOpt);
+                            appendSource(label.Pattern);
                             break;
                         }
                     case BoundUnaryOperator unary:

src/Compilers/CSharp/Portable/FlowAnalysis/AbstractFlowPass.cs

@@ -862,15 +862,6 @@ protected void RestorePending(SavedPending oldPending)
                             }
                         }
                         break;
-                    case BoundKind.PatternSwitchSection:
-                        {
-                            var sec = (BoundPatternSwitchSection)node;
-                            foreach (var label in sec.SwitchLabels)
-                            {
-                                stateChangedAfterUse |= ResolveBranches(label.Label, sec);
-                            }
-                        }
-                        break;
                     default:
                         // there are no other kinds of labels
                         throw ExceptionUtilities.UnexpectedValue(node.Kind);

src/Compilers/CSharp/Portable/Lowering/AsyncRewriter/AsyncRewriter.cs

@@ -52,12 +52,12 @@ internal partial class AsyncRewriter : StateMachineRewriter
                 method.IsIAsyncEnumeratorReturningAsync(compilation);
             if (isAsyncEnumerableOrEnumerator && !method.IsIterator)
             {
-                bool containsAwait = AwaitDetector.ContainsAwait(body);
+                bool containsAwait = AwaitDetector.ContainsAwait(bodyWithAwaitLifted);
                 diagnostics.Add(containsAwait ? ErrorCode.ERR_PossibleAsyncIteratorWithoutYield : ErrorCode.ERR_PossibleAsyncIteratorWithoutYieldOrAwait,
                     method.Locations[0], method.ReturnType);
 
                 stateMachineType = null;
-                return body;
+                return bodyWithAwaitLifted;
             }
 
             // The CLR doesn't support adding fields to structs, so in order to enable EnC in an async method we need to generate a class.

src/Compilers/CSharp/Portable/Lowering/LocalRewriter/LocalRewriter_Patterns.cs

@@ -216,7 +216,7 @@ void addArg(RefKind refKind, BoundExpression expression)
                         {
                             // This is an evaluation of an indexed property with a constant int value.
                             // The input type must be ITuple, and the property must be a property of ITuple.
-                            Debug.Assert(e.Property.ContainingSymbol == input.Type);
+                            Debug.Assert(e.Property.ContainingSymbol.Equals(input.Type));
                             Debug.Assert(e.Property.GetMethod.ParameterCount == 1);
                             Debug.Assert(e.Property.GetMethod.Parameters[0].Type.SpecialType == SpecialType.System_Int32);
                             TypeSymbol type = e.Property.GetMethod.ReturnType.TypeSymbol;
@@ -260,7 +260,7 @@ protected BoundExpression LowerTest(BoundDagTest test)
 
             private BoundExpression MakeEqual(BoundExpression loweredLiteral, BoundExpression input)
             {
-                Debug.Assert(loweredLiteral.Type == input.Type);
+                Debug.Assert(loweredLiteral.Type.Equals(input.Type, TypeCompareKind.AllIgnoreOptions));
 
                 if (loweredLiteral.Type.SpecialType == SpecialType.System_Double && double.IsNaN(loweredLiteral.ConstantValue.DoubleValue))
                 {
@@ -340,7 +340,7 @@ private BoundExpression MakeEqual(BoundExpression loweredLiteral, BoundExpressio
                 if (test is BoundDagTypeTest typeDecision &&
                     evaluation is BoundDagTypeEvaluation typeEvaluation &&
                     typeDecision.Type.IsReferenceType &&
-                    typeEvaluation.Type == typeDecision.Type &&
+                    typeEvaluation.Type.Equals(typeDecision.Type, TypeCompareKind.AllIgnoreOptions) &&
                     typeEvaluation.Input == typeDecision.Input
                     )
                 {

src/Compilers/CSharp/Portable/Parser/LanguageParser_Patterns.cs

@@ -47,7 +47,7 @@ private CSharpSyntaxNode ParseTypeOrPatternForIsOperatorCore()
             switch (tk)
             {
                 case SyntaxKind.IdentifierToken when this.CurrentToken.ContextualKind == SyntaxKind.UnderscoreToken:
-                    // We permit a type named `_` on the right-hand-side of an is operator, but not inside of a pattern.
+                // We permit a type named `_` on the right-hand-side of an is operator, but not inside of a pattern.
                 case SyntaxKind.CloseParenToken:
                 case SyntaxKind.CloseBracketToken:
                 case SyntaxKind.CloseBraceToken:
@@ -557,7 +557,7 @@ private PropertyPatternClauseSyntax ParsePropertyPatternClause()
             var list = _pool.AllocateSeparated<SubpatternSyntax>();
             try
             {
-                tryAgain:
+tryAgain:
 
                 if (this.IsPossibleSubpatternElement() || this.CurrentToken.Kind == SyntaxKind.CommaToken)
                 {

src/Compilers/Core/Portable/Microsoft.CodeAnalysis.csproj

@@ -21,12 +21,8 @@
       Do not install this package manually, it will be added as a prerequisite by other packages that require it.
     </PackageDescription>
   </PropertyGroup>
-  <PropertyGroup Condition="'$(Configuration)|$(Platform)' == 'Debug|AnyCPU'">
-    <LangVersion>7.2</LangVersion>
-  </PropertyGroup>
-  <PropertyGroup Condition="'$(Configuration)|$(Platform)' == 'Release|AnyCPU'">
-    <LangVersion>7.2</LangVersion>
-  </PropertyGroup>
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)' == 'Debug|AnyCPU'" />
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)' == 'Release|AnyCPU'" />
   <ItemGroup>
     <Content Include="$(NuGetPackageRoot)\microsoft.diasymreader.native\$(MicrosoftDiaSymReaderNativeVersion)\runtimes\win\native\Microsoft.DiaSymReader.Native.x86.dll">
       <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>

src/Compilers/VisualBasic/Test/Symbol/SymbolsTests/WellKnownTypeValidationTests.vb

@@ -519,7 +519,7 @@ End Namespace
                          WellKnownType.System_Threading_Tasks_ValueTask_T,
                          WellKnownType.System_Threading_Tasks_ValueTask,
                          WellKnownType.System_Runtime_CompilerServices_AsyncIteratorMethodBuilder,
-                         WellKnownType.System_Threading_CancellationToken
+                         WellKnownType.System_Threading_CancellationToken,
                          WellKnownType.System_MatchFailureException,
                          WellKnownType.System_Runtime_CompilerServices_NonNullTypesAttribute,
                          WellKnownType.Microsoft_CodeAnalysis_EmbeddedAttribute
@@ -580,7 +580,7 @@ End Namespace
                          WellKnownType.System_Threading_Tasks_ValueTask_T,
                          WellKnownType.System_Threading_Tasks_ValueTask,
                          WellKnownType.System_Runtime_CompilerServices_AsyncIteratorMethodBuilder,
-                         WellKnownType.System_Threading_CancellationToken
+                         WellKnownType.System_Threading_CancellationToken,
                          WellKnownType.System_MatchFailureException,
                          WellKnownType.System_Runtime_CompilerServices_NonNullTypesAttribute,
                          WellKnownType.Microsoft_CodeAnalysis_EmbeddedAttribute