Remove symbol chain cache

Author: dbaeumer

src/compiler/checker.ts

@@ -375,9 +375,6 @@ namespace ts {
         // extra cost of calling `getParseTreeNode` when calling these functions from inside the
         // checker.
         const checker: TypeChecker = {
-            setSymbolChainCache: (cache: SymbolChainCache | undefined): void => {
-                nodeBuilder.setSymbolChainCache(cache);
-            },
             getNodeCount: () => sum(host.getSourceFiles(), "nodeCount"),
             getIdentifierCount: () => sum(host.getSourceFiles(), "identifierCount"),
             getSymbolCount: () => sum(host.getSourceFiles(), "symbolCount") + symbolCount,
@@ -4497,9 +4494,7 @@ namespace ts {
         }
 
         function createNodeBuilder() {
-            let symbolChainCache: SymbolChainCache | undefined;
             return {
-                setSymbolChainCache: (cache: SymbolChainCache | undefined): void => { symbolChainCache = cache },
                 typeToTypeNode: (type: Type, enclosingDeclaration?: Node, flags?: NodeBuilderFlags, tracker?: SymbolTracker) =>
                     withContext(enclosingDeclaration, flags, tracker, context => typeToTypeNodeHelper(type, context)),
                 indexInfoToIndexSignatureDeclaration: (indexInfo: IndexInfo, enclosingDeclaration?: Node, flags?: NodeBuilderFlags, tracker?: SymbolTracker) =>
@@ -4537,7 +4532,6 @@ namespace ts {
                         fileExists: fileName => host.fileExists(fileName),
                         getFileIncludeReasons: () => host.getFileIncludeReasons(),
                     } : undefined },
-                    cache: symbolChainCache,
                     encounteredError: false,
                     reportedDiagnostic: false,
                     visitedTypes: undefined,
@@ -5626,30 +5620,6 @@ namespace ts {
 
                 /** @param endOfChain Set to false for recursive calls; non-recursive calls should always output something. */
                 function getSymbolChain(symbol: Symbol, meaning: SymbolFlags, endOfChain: boolean): Symbol[] | undefined {
-                    let key: SymbolChainCacheKey | undefined;
-                    let result: Symbol[] | undefined;
-                    if (context.cache) {
-                        key = {
-                            symbol,
-                            enclosingDeclaration: context.enclosingDeclaration,
-                            flags: context.flags,
-                            meaning: meaning,
-                            yieldModuleSymbol: yieldModuleSymbol,
-                            endOfChain: endOfChain
-                        }
-                        result = context.cache.lookup(key);
-                        if (result) {
-                            return result;
-                        }
-                    }
-                    result = doGetSymbolChain(symbol, meaning, endOfChain);
-                    if (result && key && context.cache) {
-                        context.cache.cache(key, result);
-                    }
-                    return result;
-                }
-
-                function doGetSymbolChain(symbol: Symbol, meaning: SymbolFlags, endOfChain: boolean): Symbol[] | undefined {
                     let accessibleSymbolChain = getAccessibleSymbolChain(symbol, context.enclosingDeclaration, meaning, !!(context.flags & NodeBuilderFlags.UseOnlyExternalAliasing));
                     let parentSpecifiers: (string | undefined)[];
                     if (!accessibleSymbolChain ||
@@ -7863,7 +7833,6 @@ namespace ts {
             enclosingDeclaration: Node | undefined;
             flags: NodeBuilderFlags;
             tracker: SymbolTracker;
-            cache: SymbolChainCache | undefined;
 
             // State
             encounteredError: boolean;

src/compiler/types.ts

@@ -4096,22 +4096,7 @@ namespace ts {
         readonly redirectTargetsMap: RedirectTargetsMap;
     }
 
-    export interface SymbolChainCacheKey {
-        symbol: Symbol;
-        enclosingDeclaration?: Node;
-        flags: NodeBuilderFlags;
-        meaning: SymbolFlags;
-        yieldModuleSymbol?: boolean;
-        endOfChain: boolean;
-    }
-
-    export interface SymbolChainCache {
-        lookup(key: SymbolChainCacheKey): Symbol[] | undefined;
-        cache(key: SymbolChainCacheKey, value: Symbol[]): void;
-    }
-
     export interface TypeChecker {
-        setSymbolChainCache(cache: SymbolChainCache | undefined): void;
         getTypeOfSymbolAtLocation(symbol: Symbol, node: Node): Type;
         getDeclaredTypeOfSymbol(symbol: Symbol): Type;
         getPropertiesOfType(type: Type): Symbol[];