Release resources after a query is executed.

src/Features/Core/Portable/AddImport/SearchScopes/SearchScope.cs

@@ -42,33 +42,35 @@ protected SearchScope(AbstractAddImportCodeFixProvider<TSimpleNameSyntax> provid
                     return ImmutableArray<SymbolResult<ISymbol>>.Empty;
                 }
 
-                var query = this.Exact ? SearchQuery.Create(name, ignoreCase: true) : SearchQuery.CreateFuzzy(name);
-                var symbols = await FindDeclarationsAsync(name, filter, query).ConfigureAwait(false);
-
-                if (Exact)
+                using (var query = this.Exact ? SearchQuery.Create(name, ignoreCase: true) : SearchQuery.CreateFuzzy(name))
                 {
-                    // We did an exact, case insensitive, search.  Case sensitive matches should
-                    // be preferred though over insensitive ones.
-                    return symbols.SelectAsArray(s =>
-                        SymbolResult.Create(s.Name, nameNode, s, weight: s.Name == name ? 0 : 1));
-                }
+                    var symbols = await FindDeclarationsAsync(name, filter, query).ConfigureAwait(false);
 
-                // TODO(cyrusn): It's a shame we have to compute this twice.  However, there's no
-                // great way to store the original value we compute because it happens deep in the 
-                // compiler bowels when we call FindDeclarations.
-                var similarityChecker = WordSimilarityChecker.Allocate(name, substringsAreSimilar: false);
+                    if (Exact)
+                    {
+                        // We did an exact, case insensitive, search.  Case sensitive matches should
+                        // be preferred though over insensitive ones.
+                        return symbols.SelectAsArray(s =>
+                            SymbolResult.Create(s.Name, nameNode, s, weight: s.Name == name ? 0 : 1));
+                    }
 
-                var result = symbols.SelectAsArray(s =>
-                {
-                    var areSimilar = similarityChecker.AreSimilar(s.Name, out var matchCost);
+                    // TODO(cyrusn): It's a shame we have to compute this twice.  However, there's no
+                    // great way to store the original value we compute because it happens deep in the 
+                    // compiler bowels when we call FindDeclarations.
+                    var similarityChecker = WordSimilarityChecker.Allocate(name, substringsAreSimilar: false);
 
-                    Debug.Assert(areSimilar);
-                    return SymbolResult.Create(s.Name, nameNode, s, matchCost);
-                });
+                    var result = symbols.SelectAsArray(s =>
+                    {
+                        var areSimilar = similarityChecker.AreSimilar(s.Name, out var matchCost);
 
-                similarityChecker.Free();
+                        Debug.Assert(areSimilar);
+                        return SymbolResult.Create(s.Name, nameNode, s, matchCost);
+                    });
 
-                return result;
+                    similarityChecker.Free();
+
+                    return result;
+                }
             }
         }
     }

src/Workspaces/Core/Portable/FindSymbols/Declarations/DeclarationFinder_SourceDeclarations.cs

@@ -183,26 +183,31 @@ internal static partial class DeclarationFinder
         internal static async Task<ImmutableArray<SymbolAndProjectId>> FindSourceDeclarationsWithNormalQueryInCurrentProcessAsync(
             Solution solution, string name, bool ignoreCase, SymbolFilter criteria, CancellationToken cancellationToken)
         {
-            var query = SearchQuery.Create(name, ignoreCase);
-            var result = ArrayBuilder<SymbolAndProjectId>.GetInstance();
-            foreach (var projectId in solution.ProjectIds)
+            using (var query = SearchQuery.Create(name, ignoreCase))
             {
-                var project = solution.GetProject(projectId);
-                await AddCompilationDeclarationsWithNormalQueryAsync(
-                    project, query, criteria, result, cancellationToken).ConfigureAwait(false);
-            }
+                var result = ArrayBuilder<SymbolAndProjectId>.GetInstance();
+                foreach (var projectId in solution.ProjectIds)
+                {
+                    var project = solution.GetProject(projectId);
+                    await AddCompilationDeclarationsWithNormalQueryAsync(
+                        project, query, criteria, result, cancellationToken).ConfigureAwait(false);
+                }
 
-            return result.ToImmutableAndFree();
+                return result.ToImmutableAndFree();
+            }
         }
 
         internal static async Task<ImmutableArray<SymbolAndProjectId>> FindSourceDeclarationsWithNormalQueryInCurrentProcessAsync(
             Project project, string name, bool ignoreCase, SymbolFilter filter, CancellationToken cancellationToken)
         {
             var list = ArrayBuilder<SymbolAndProjectId>.GetInstance();
-            await AddCompilationDeclarationsWithNormalQueryAsync(
-                project, SearchQuery.Create(name, ignoreCase),
-                filter, list, cancellationToken).ConfigureAwait(false);
-            return list.ToImmutableAndFree();
+
+            using (var query = SearchQuery.Create(name, ignoreCase))
+            {
+                await AddCompilationDeclarationsWithNormalQueryAsync(
+                    project, query, filter, list, cancellationToken).ConfigureAwait(false);
+                return list.ToImmutableAndFree();
+            }
         }
 
         internal static async Task<ImmutableArray<SymbolAndProjectId>> FindSourceDeclarationsWithPatternInCurrentProcessAsync(
@@ -215,36 +220,38 @@ internal static partial class DeclarationFinder
             // we only want to check the 'WL' portion.  Then, after we get all the candidate symbols
             // we'll check if the full name matches the full pattern.
             var patternMatcher = new PatternMatcher(pattern);
-            var query = SearchQuery.CreateCustom(
-                k => !patternMatcher.GetMatchesForLastSegmentOfPattern(k).IsDefaultOrEmpty);
-
-            var symbolAndProjectIds = await SymbolFinder.FindSourceDeclarationsWithCustomQueryAsync(
-                project, query, criteria, cancellationToken).ConfigureAwait(false);
-
-            var result = ArrayBuilder<SymbolAndProjectId>.GetInstance();
-
-            // Now see if the symbols the compiler returned actually match the full pattern.
-            foreach (var symbolAndProjectId in symbolAndProjectIds)
+            using (var query = SearchQuery.CreateCustom(
+                k => !patternMatcher.GetMatchesForLastSegmentOfPattern(k).IsDefaultOrEmpty))
             {
-                var symbol = symbolAndProjectId.Symbol;
 
-                // As an optimization, don't bother getting the container for this symbol if this
-                // isn't a dotted pattern.  Getting the container could cause lots of string 
-                // allocations that we don't if we're never going to check it.
-                var matches = !patternMatcher.IsDottedPattern
-                    ? new PatternMatches(patternMatcher.GetMatches(GetSearchName(symbol)))
-                    : patternMatcher.GetMatches(GetSearchName(symbol), GetContainer(symbol));
+                var symbolAndProjectIds = await SymbolFinder.FindSourceDeclarationsWithCustomQueryAsync(
+                    project, query, criteria, cancellationToken).ConfigureAwait(false);
+
+                var result = ArrayBuilder<SymbolAndProjectId>.GetInstance();
 
-                if (matches.IsEmpty)
+                // Now see if the symbols the compiler returned actually match the full pattern.
+                foreach (var symbolAndProjectId in symbolAndProjectIds)
                 {
-                    // Didn't actually match the full pattern, ignore it.
-                    continue;
+                    var symbol = symbolAndProjectId.Symbol;
+
+                    // As an optimization, don't bother getting the container for this symbol if this
+                    // isn't a dotted pattern.  Getting the container could cause lots of string 
+                    // allocations that we don't if we're never going to check it.
+                    var matches = !patternMatcher.IsDottedPattern
+                        ? new PatternMatches(patternMatcher.GetMatches(GetSearchName(symbol)))
+                        : patternMatcher.GetMatches(GetSearchName(symbol), GetContainer(symbol));
+
+                    if (matches.IsEmpty)
+                    {
+                        // Didn't actually match the full pattern, ignore it.
+                        continue;
+                    }
+
+                    result.Add(symbolAndProjectId);
                 }
 
-                result.Add(symbolAndProjectId);
+                return result.ToImmutableAndFree();
             }
-
-            return result.ToImmutableAndFree();
         }
 
         private static string GetSearchName(ISymbol symbol)

src/Workspaces/Core/Portable/FindSymbols/SearchQuery.cs

@@ -5,7 +5,7 @@
 
 namespace Microsoft.CodeAnalysis.FindSymbols
 {
-    internal class SearchQuery
+    internal class SearchQuery : IDisposable
     {
         /// <summary>The name being searched for.  Is null in the case of custom predicate searching..  But 
         /// can be used for faster index based searching when it is available.</summary> 
@@ -18,6 +18,8 @@ internal class SearchQuery
         ///<summary>The predicate to fall back on if faster index searching is not possible.</summary>
         private readonly Func<string, bool> _predicate;
 
+        private readonly WordSimilarityChecker _wordSimilarityChecker;
+
         private SearchQuery(string name, SearchKind kind)
         {
             Name = name ?? throw new ArgumentNullException(nameof(name));
@@ -36,8 +38,8 @@ private SearchQuery(string name, SearchKind kind)
                     // its 'AreSimilar' method. That way we only create the WordSimilarityChecker
                     // once and it can cache all the information it needs while it does the AreSimilar
                     // check against all the possible candidates.
-                    var editDistance = WordSimilarityChecker.Allocate(name, substringsAreSimilar: false);
-                    _predicate = editDistance.AreSimilar;
+                    _wordSimilarityChecker = WordSimilarityChecker.Allocate(name, substringsAreSimilar: false);
+                    _predicate = _wordSimilarityChecker.AreSimilar;
                     break;
                 default:
                     throw ExceptionUtilities.UnexpectedValue(kind);
@@ -50,6 +52,11 @@ private SearchQuery(Func<string, bool> predicate)
             _predicate = predicate ?? throw new ArgumentNullException(nameof(predicate));
         }
 
+        public void Dispose()
+        {
+            _wordSimilarityChecker?.Free();
+        }
+
         public static SearchQuery Create(string name, SearchKind kind)
             => new SearchQuery(name, kind);
 

src/Workspaces/Core/Portable/FindSymbols/SymbolFinder_Declarations_AllDeclarations.cs

@@ -14,9 +14,12 @@ public static partial class SymbolFinder
         public static async Task<IEnumerable<ISymbol>> FindDeclarationsAsync(
             Project project, string name, bool ignoreCase, CancellationToken cancellationToken = default(CancellationToken))
         {
-            var declarations = await DeclarationFinder.FindAllDeclarationsWithNormalQueryAsync(
-                project, SearchQuery.Create(name, ignoreCase), SymbolFilter.All, cancellationToken).ConfigureAwait(false);
-            return declarations.SelectAsArray(t => t.Symbol);
+            using (var query = SearchQuery.Create(name, ignoreCase))
+            {
+                var declarations = await DeclarationFinder.FindAllDeclarationsWithNormalQueryAsync(
+                    project, query, SymbolFilter.All, cancellationToken).ConfigureAwait(false);
+                return declarations.SelectAsArray(t => t.Symbol);
+            }
         }
 
         /// <summary>
@@ -25,9 +28,12 @@ public static partial class SymbolFinder
         public static async Task<IEnumerable<ISymbol>> FindDeclarationsAsync(
             Project project, string name, bool ignoreCase, SymbolFilter filter, CancellationToken cancellationToken = default(CancellationToken))
         {
-            var declarations = await DeclarationFinder.FindAllDeclarationsWithNormalQueryAsync(
-                project, SearchQuery.Create(name, ignoreCase), filter, cancellationToken).ConfigureAwait(false);
-            return declarations.SelectAsArray(t => t.Symbol);
+            using (var query = SearchQuery.Create(name, ignoreCase))
+            {
+                var declarations = await DeclarationFinder.FindAllDeclarationsWithNormalQueryAsync(
+                    project, query, filter, cancellationToken).ConfigureAwait(false);
+                return declarations.SelectAsArray(t => t.Symbol);
+            }
         }
     }
 }
\ No newline at end of file

src/Workspaces/Core/Portable/FindSymbols/SymbolFinder_Declarations_CustomQueries.cs

@@ -30,10 +30,13 @@ public static Task<IEnumerable<ISymbol>> FindSourceDeclarationsAsync(Solution so
         /// </summary>
         public static async Task<IEnumerable<ISymbol>> FindSourceDeclarationsAsync(Solution solution, Func<string, bool> predicate, SymbolFilter filter, CancellationToken cancellationToken = default(CancellationToken))
         {
-            var declarations = await FindSourceDeclarationsWithCustomQueryAsync(
-                solution, SearchQuery.CreateCustom(predicate), filter, cancellationToken).ConfigureAwait(false);
+            using (var query = SearchQuery.CreateCustom(predicate))
+            {
+                var declarations = await FindSourceDeclarationsWithCustomQueryAsync(
+                    solution, query, filter, cancellationToken).ConfigureAwait(false);
 
-            return declarations.SelectAsArray(d => d.Symbol);
+                return declarations.SelectAsArray(d => d.Symbol);
+            }
         }
 
         private static async Task<ImmutableArray<SymbolAndProjectId>> FindSourceDeclarationsWithCustomQueryAsync(
@@ -74,10 +77,13 @@ public static Task<IEnumerable<ISymbol>> FindSourceDeclarationsAsync(Project pro
         /// </summary>
         public static async Task<IEnumerable<ISymbol>> FindSourceDeclarationsAsync(Project project, Func<string, bool> predicate, SymbolFilter filter, CancellationToken cancellationToken = default(CancellationToken))
         {
-            var declarations = await FindSourceDeclarationsWithCustomQueryAsync(
-                project, SearchQuery.CreateCustom(predicate), filter, cancellationToken).ConfigureAwait(false);
+            using (var query = SearchQuery.CreateCustom(predicate))
+            {
+                var declarations = await FindSourceDeclarationsWithCustomQueryAsync(
+                    project, query, filter, cancellationToken).ConfigureAwait(false);
 
-            return declarations.SelectAsArray(d => d.Symbol);
+                return declarations.SelectAsArray(d => d.Symbol);
+            }
         }
 
         internal static async Task<ImmutableArray<SymbolAndProjectId>> FindSourceDeclarationsWithCustomQueryAsync(

src/Workspaces/Remote/ServiceHub/Services/CodeAnalysisService_SymbolFinder.cs

@@ -50,10 +50,13 @@ public async Task FindLiteralReferencesAsync(object value)
             var solution = await GetSolutionAsync().ConfigureAwait(false);
             var project = solution.GetProject(projectId);
 
-            var result = await DeclarationFinder.FindAllDeclarationsWithNormalQueryInCurrentProcessAsync(
-                project, SearchQuery.Create(name, searchKind), criteria, this.CancellationToken).ConfigureAwait(false);
+            using (var query = SearchQuery.Create(name, searchKind))
+            {
+                var result = await DeclarationFinder.FindAllDeclarationsWithNormalQueryInCurrentProcessAsync(
+                    project, query, criteria, this.CancellationToken).ConfigureAwait(false);
 
-            return result.Select(SerializableSymbolAndProjectId.Dehydrate).ToArray();
+                return result.Select(SerializableSymbolAndProjectId.Dehydrate).ToArray();
+            }
         }
 
         public async Task<SerializableSymbolAndProjectId[]> FindSolutionSourceDeclarationsWithNormalQueryAsync(