Merge diagnosticsProducing and nonDiagnosticsProducing checkers into a single checker supporting lazy diagnostics (#36747)

* Merge diagnosticsProducing and nonDiagnosticsProducing checkers into a single checker supporting lazy diagnostics

* Fix lint

Author: weswigham

src/compiler/checker.ts

@@ -1025,8 +1025,7 @@ namespace ts {
         let files: SourceFile[];
         let symlinks: SymlinkCache | undefined;
         let commonSourceDirectory: string;
-        let diagnosticsProducingTypeChecker: TypeChecker;
-        let noDiagnosticsTypeChecker: TypeChecker;
+        let typeChecker: TypeChecker;
         let classifiableNames: Set<__String>;
         const ambientModuleNameToUnmodifiedFileName = new Map<string, string>();
         let fileReasons = createMultiMap<Path, FileIncludeReason>();
@@ -1304,21 +1303,19 @@ namespace ts {
             getProgramDiagnostics,
             getTypeChecker,
             getClassifiableNames,
-            getDiagnosticsProducingTypeChecker,
             getCommonSourceDirectory,
             emit,
             getCurrentDirectory: () => currentDirectory,
-            getNodeCount: () => getDiagnosticsProducingTypeChecker().getNodeCount(),
-            getIdentifierCount: () => getDiagnosticsProducingTypeChecker().getIdentifierCount(),
-            getSymbolCount: () => getDiagnosticsProducingTypeChecker().getSymbolCount(),
-            getTypeCount: () => getDiagnosticsProducingTypeChecker().getTypeCount(),
-            getInstantiationCount: () => getDiagnosticsProducingTypeChecker().getInstantiationCount(),
-            getRelationCacheSizes: () => getDiagnosticsProducingTypeChecker().getRelationCacheSizes(),
+            getNodeCount: () => getTypeChecker().getNodeCount(),
+            getIdentifierCount: () => getTypeChecker().getIdentifierCount(),
+            getSymbolCount: () => getTypeChecker().getSymbolCount(),
+            getTypeCount: () => getTypeChecker().getTypeCount(),
+            getInstantiationCount: () => getTypeChecker().getInstantiationCount(),
+            getRelationCacheSizes: () => getTypeChecker().getRelationCacheSizes(),
             getFileProcessingDiagnostics: () => fileProcessingDiagnostics,
             getResolvedTypeReferenceDirectives: () => resolvedTypeReferenceDirectives,
             isSourceFileFromExternalLibrary,
             isSourceFileDefaultLibrary,
-            dropDiagnosticsProducingTypeChecker,
             getSourceFileFromReference,
             getLibFileFromReference,
             sourceFileToPackageName,
@@ -1980,16 +1977,8 @@ namespace ts {
             }
         }
 
-        function getDiagnosticsProducingTypeChecker() {
-            return diagnosticsProducingTypeChecker || (diagnosticsProducingTypeChecker = createTypeChecker(program, /*produceDiagnostics:*/ true));
-        }
-
-        function dropDiagnosticsProducingTypeChecker() {
-            diagnosticsProducingTypeChecker = undefined!;
-        }
-
         function getTypeChecker() {
-            return noDiagnosticsTypeChecker || (noDiagnosticsTypeChecker = createTypeChecker(program, /*produceDiagnostics:*/ false));
+            return typeChecker || (typeChecker = createTypeChecker(program));
         }
 
         function emit(sourceFile?: SourceFile, writeFileCallback?: WriteFileCallback, cancellationToken?: CancellationToken, emitOnlyDtsFiles?: boolean, transformers?: CustomTransformers, forceDtsEmit?: boolean): EmitResult {
@@ -2017,7 +2006,7 @@ namespace ts {
             // This is because in the -out scenario all files need to be emitted, and therefore all
             // files need to be type checked. And the way to specify that all files need to be type
             // checked is to not pass the file to getEmitResolver.
-            const emitResolver = getDiagnosticsProducingTypeChecker().getEmitResolver(outFile(options) ? undefined : sourceFile, cancellationToken);
+            const emitResolver = getTypeChecker().getEmitResolver(outFile(options) ? undefined : sourceFile, cancellationToken);
 
             performance.mark("beforeEmit");
 
@@ -2121,15 +2110,7 @@ namespace ts {
                 if (e instanceof OperationCanceledException) {
                     // We were canceled while performing the operation.  Because our type checker
                     // might be a bad state, we need to throw it away.
-                    //
-                    // Note: we are overly aggressive here.  We do not actually *have* to throw away
-                    // the "noDiagnosticsTypeChecker".  However, for simplicity, i'd like to keep
-                    // the lifetimes of these two TypeCheckers the same.  Also, we generally only
-                    // cancel when the user has made a change anyways.  And, in that case, we (the
-                    // program instance) will get thrown away anyways.  So trying to keep one of
-                    // these type checkers alive doesn't serve much purpose.
-                    noDiagnosticsTypeChecker = undefined!;
-                    diagnosticsProducingTypeChecker = undefined!;
+                    typeChecker = undefined!;
                 }
 
                 throw e;
@@ -2153,7 +2134,7 @@ namespace ts {
                     return emptyArray;
                 }
 
-                const typeChecker = getDiagnosticsProducingTypeChecker();
+                const typeChecker = getTypeChecker();
 
                 Debug.assert(!!sourceFile.bindDiagnostics);
 
@@ -2209,7 +2190,7 @@ namespace ts {
 
         function getSuggestionDiagnostics(sourceFile: SourceFile, cancellationToken: CancellationToken): readonly DiagnosticWithLocation[] {
             return runWithCancellationToken(() => {
-                return getDiagnosticsProducingTypeChecker().getSuggestionDiagnostics(sourceFile, cancellationToken);
+                return getTypeChecker().getSuggestionDiagnostics(sourceFile, cancellationToken);
             });
         }
 
@@ -2446,7 +2427,7 @@ namespace ts {
 
         function getDeclarationDiagnosticsForFileNoCache(sourceFile: SourceFile | undefined, cancellationToken: CancellationToken | undefined): readonly DiagnosticWithLocation[] {
             return runWithCancellationToken(() => {
-                const resolver = getDiagnosticsProducingTypeChecker().getEmitResolver(sourceFile, cancellationToken);
+                const resolver = getTypeChecker().getEmitResolver(sourceFile, cancellationToken);
                 // Don't actually write any files since we're just getting diagnostics.
                 return ts.getDeclarationDiagnostics(getEmitHost(noop), resolver, sourceFile) || emptyArray;
             });
@@ -2497,7 +2478,7 @@ namespace ts {
         }
 
         function getGlobalDiagnostics(): SortedReadonlyArray<Diagnostic> {
-            return rootNames.length ? sortAndDeduplicateDiagnostics(getDiagnosticsProducingTypeChecker().getGlobalDiagnostics().slice()) : emptyArray as any as SortedReadonlyArray<Diagnostic>;
+            return rootNames.length ? sortAndDeduplicateDiagnostics(getTypeChecker().getGlobalDiagnostics().slice()) : emptyArray as any as SortedReadonlyArray<Diagnostic>;
         }
 
         function getConfigFileParsingDiagnostics(): readonly Diagnostic[] {

src/compiler/program.ts

@@ -4016,11 +4016,6 @@ namespace ts {
 
         /* @internal */ getCommonSourceDirectory(): string;
 
-        // For testing purposes only.  Should not be used by any other consumers (including the
-        // language service).
-        /* @internal */ getDiagnosticsProducingTypeChecker(): TypeChecker;
-        /* @internal */ dropDiagnosticsProducingTypeChecker(): void;
-
         /* @internal */ getCachedSemanticDiagnostics(sourceFile?: SourceFile): readonly Diagnostic[] | undefined;
 
         /* @internal */ getClassifiableNames(): Set<__String>;

src/compiler/types.ts

@@ -717,7 +717,7 @@ namespace Harness {
             // These types are equivalent, but depend on what order the compiler observed
             // certain parts of the program.
 
-            const fullWalker = new TypeWriterWalker(program, /*fullTypeCheck*/ true, !!hasErrorBaseline);
+            const fullWalker = new TypeWriterWalker(program, !!hasErrorBaseline);
 
             // Produce baselines.  The first gives the types for all expressions.
             // The second gives symbols for all identifiers.

src/harness/harnessIO.ts

@@ -41,12 +41,10 @@ namespace Harness {
 
         private checker: ts.TypeChecker;
 
-        constructor(private program: ts.Program, fullTypeCheck: boolean, private hadErrorBaseline: boolean) {
+        constructor(private program: ts.Program, private hadErrorBaseline: boolean) {
             // Consider getting both the diagnostics checker and the non-diagnostics checker to verify
             // they are consistent.
-            this.checker = fullTypeCheck
-                ? program.getDiagnosticsProducingTypeChecker()
-                : program.getTypeChecker();
+            this.checker = program.getTypeChecker();
         }
 
         public *getSymbols(fileName: string): IterableIterator<TypeWriterSymbolResult> {

src/harness/typeWriter.ts

@@ -13,7 +13,7 @@ namespace ts.codefix {
         errorCodes,
         getCodeActions: function getCodeActionsToAddMissingAsync(context) {
             const { sourceFile, errorCode, cancellationToken, program, span } = context;
-            const diagnostic = find(program.getDiagnosticsProducingTypeChecker().getDiagnostics(sourceFile, cancellationToken), getIsMatchingAsyncError(span, errorCode));
+            const diagnostic = find(program.getTypeChecker().getDiagnostics(sourceFile, cancellationToken), getIsMatchingAsyncError(span, errorCode));
             const directSpan = diagnostic && diagnostic.relatedInformation && find(diagnostic.relatedInformation, r => r.code === Diagnostics.Did_you_mean_to_mark_this_function_as_async.code) as TextSpan | undefined;
 
             const decl = getFixableErrorSpanDeclaration(sourceFile, directSpan);

src/services/codefixes/addMissingAsync.ts

@@ -93,7 +93,7 @@ namespace ts.codefix {
     }
 
     function isMissingAwaitError(sourceFile: SourceFile, errorCode: number, span: TextSpan, cancellationToken: CancellationToken, program: Program) {
-        const checker = program.getDiagnosticsProducingTypeChecker();
+        const checker = program.getTypeChecker();
         const diagnostics = checker.getDiagnostics(sourceFile, cancellationToken);
         return some(diagnostics, ({ start, length, relatedInformation, code }) =>
             isNumber(start) && isNumber(length) && textSpansEqual({ start, length }, span) &&