Make local functions static.

src/Features/Core/Portable/CodeFixes/Suppression/AbstractSuppressionCodeFixProvider.PragmaBatchFixHelpers.cs

@@ -131,9 +131,9 @@ private static class PragmaBatchFixHelpers
 
             private static void UpdateDiagnosticSpans(ImmutableArray<Diagnostic> diagnostics, Dictionary<Diagnostic, TextSpan> currentDiagnosticSpans, IEnumerable<TextChange> textChanges)
             {
-                bool isPriorSpan(TextSpan span, TextChange textChange) => span.End <= textChange.Span.Start;
-                bool isFollowingSpan(TextSpan span, TextChange textChange) => span.Start >= textChange.Span.End;
-                bool isEnclosingSpan(TextSpan span, TextChange textChange) => span.Contains(textChange.Span);
+                static bool isPriorSpan(TextSpan span, TextChange textChange) => span.End <= textChange.Span.Start;
+                static bool isFollowingSpan(TextSpan span, TextChange textChange) => span.Start >= textChange.Span.End;
+                static bool isEnclosingSpan(TextSpan span, TextChange textChange) => span.Contains(textChange.Span);
 
                 foreach (var diagnostic in diagnostics)
                 {

src/Features/Core/Portable/Completion/Providers/AbstractInternalsVisibleToCompletionProvider.cs

@@ -250,7 +250,7 @@ private static async Task<TextSpan> GetTextChangeSpanAsync(Document document, Te
                 var text = root.GetText();
 
                 // Expand selection in both directions until a double quote or any line break character is reached
-                bool IsWordCharacter(char ch) => !(ch == '"' || TextUtilities.IsAnyLineBreakCharacter(ch));
+                static bool IsWordCharacter(char ch) => !(ch == '"' || TextUtilities.IsAnyLineBreakCharacter(ch));
 
                 result = CommonCompletionUtilities.GetWordSpan(
                     text, startSpan.Start, IsWordCharacter, IsWordCharacter, alwaysExtendEndSpan: true);

src/Features/Core/Portable/Diagnostics/Analyzers/UnboundIdentifiersDiagnosticAnalyzerBase.cs

@@ -67,7 +67,7 @@ private static bool IsBrokenLambda(SyntaxNodeAnalysisContext context)
 
         private void ReportUnboundIdentifierNames(SyntaxNodeAnalysisContext context, SyntaxNode member)
         {
-            bool isQualifiedOrSimpleName(SyntaxNode n) => n is TQualifiedNameSyntax || n is TSimpleNameSyntax;
+            static bool isQualifiedOrSimpleName(SyntaxNode n) => n is TQualifiedNameSyntax || n is TSimpleNameSyntax;
             var typeNames = member.DescendantNodes().Where(n => isQualifiedOrSimpleName(n) && !n.Span.IsEmpty);
             foreach (var typeName in typeNames)
             {

src/Features/Core/Portable/ExtractMethod/AbstractSyntaxTriviaService.cs

@@ -95,12 +95,14 @@ public ITriviaSavedResult SaveTriviaAroundSelection(SyntaxNode root, TextSpan te
             var triviaAtBeginning = SplitTrivia(tokens[TriviaLocation.BeforeBeginningOfSpan], tokens[TriviaLocation.AfterBeginningOfSpan], t => t.FullSpan.End <= textSpan.Start);
             var triviaAtEnd = SplitTrivia(tokens[TriviaLocation.BeforeEndOfSpan], tokens[TriviaLocation.AfterEndOfSpan], t => t.FullSpan.Start < textSpan.End);
 
-            var triviaList = new Dictionary<TriviaLocation, IEnumerable<SyntaxTrivia>>();
-            triviaList[TriviaLocation.BeforeBeginningOfSpan] = triviaAtBeginning.Item1;
-            triviaList[TriviaLocation.AfterBeginningOfSpan] = triviaAtBeginning.Item2;
+            var triviaList = new Dictionary<TriviaLocation, IEnumerable<SyntaxTrivia>>
+            {
+                [TriviaLocation.BeforeBeginningOfSpan] = triviaAtBeginning.Item1,
+                [TriviaLocation.AfterBeginningOfSpan] = triviaAtBeginning.Item2,
 
-            triviaList[TriviaLocation.BeforeEndOfSpan] = triviaAtEnd.Item1;
-            triviaList[TriviaLocation.AfterEndOfSpan] = triviaAtEnd.Item2;
+                [TriviaLocation.BeforeEndOfSpan] = triviaAtEnd.Item1,
+                [TriviaLocation.AfterEndOfSpan] = triviaAtEnd.Item2
+            };
             return triviaList;
         }
 

src/Features/Core/Portable/IntroduceVariable/AbstractIntroduceVariableService.cs

@@ -340,8 +340,7 @@ where NodeMatchesExpression(originalSemanticModel, currentSemanticModel, express
             }
 
             return false;
-
-            bool IsInstanceMemberReference(IOperation operation)
+            static bool IsInstanceMemberReference(IOperation operation)
                 => operation is IMemberReferenceOperation memberReferenceOperation &&
                     memberReferenceOperation.Instance?.Kind == OperationKind.InstanceReference;
         }

src/Features/Core/Portable/MakeFieldReadonly/MakeFieldReadonlyDiagnosticAnalyzer.cs

@@ -101,7 +101,7 @@ void OnSymbolEnd(SymbolAnalysisContext symbolEndContext)
                     }
                 }
 
-                bool IsCandidateField(IFieldSymbol symbol) =>
+                static bool IsCandidateField(IFieldSymbol symbol) =>
                         symbol.DeclaredAccessibility == Accessibility.Private &&
                         !symbol.IsReadOnly &&
                         !symbol.IsConst &&
@@ -137,7 +137,7 @@ void UpdateFieldStateOnWrite(IFieldSymbol field)
                 }
 
                 // Method to compute the initial field state.
-                (bool isCandidate, bool written) ComputeInitialFieldState(IFieldSymbol field, AnalyzerOptions options, CancellationToken cancellationToken)
+                static (bool isCandidate, bool written) ComputeInitialFieldState(IFieldSymbol field, AnalyzerOptions options, CancellationToken cancellationToken)
                 {
                     Debug.Assert(IsCandidateField(field));
 

src/Features/Core/Portable/RemoveUnusedParametersAndValues/AbstractRemoveUnusedParametersAndValuesDiagnosticAnalyzer.SymbolStartAnalyzer.BlockAnalyzer.cs

@@ -590,7 +590,7 @@ bool IsRemovableAssignmentWithoutSideEffects(IOperation unusedSymbolWriteOperati
                         return false;
                     }
 
-                    bool IsRemovableAssignmentValueWithoutSideEffects(IOperation assignmentValue)
+                    static bool IsRemovableAssignmentValueWithoutSideEffects(IOperation assignmentValue)
                     {
                         if (assignmentValue.ConstantValue.HasValue)
                         {