Allow @check directives to switch on/off checking in a file

Author: mhegazy

src/compiler/parser.ts

@@ -5817,7 +5817,7 @@ namespace ts {
             const typeReferenceDirectives: FileReference[] = [];
             const amdDependencies: { path: string; name: string }[] = [];
             let amdModuleName: string;
-            let hasCheckDirective = false;
+            let checkJsDirective: CheckJsDirective = undefined;
 
             // Keep scanning all the leading trivia in the file until we get to something that
             // isn't trivia.  Any single line comment will be analyzed to see if it is a
@@ -5880,16 +5880,23 @@ namespace ts {
                         }
                     }
 
-                    const checkDirectiveRegEx = /^\/\/\s*@check\s*/gim;
-                    hasCheckDirective = hasCheckDirective || !!checkDirectiveRegEx.exec(comment);
+                    const checkJsDirectiveRegEx = /^\/\/\/?\s*@check(\s+(true|false))?/gim;
+                    const checkJsDirectiveMatchResult = checkJsDirectiveRegEx.exec(comment);
+                    if (checkJsDirectiveMatchResult) {
+                        checkJsDirective = {
+                            enabled: compareStrings(checkJsDirectiveMatchResult[2], "false", /*ignoreCase*/ true) !== Comparison.EqualTo,
+                            end: range.end,
+                            pos: range.pos
+                        };
+                    }
                 }
             }
 
             sourceFile.referencedFiles = referencedFiles;
             sourceFile.typeReferenceDirectives = typeReferenceDirectives;
             sourceFile.amdDependencies = amdDependencies;
             sourceFile.moduleName = amdModuleName;
-            sourceFile.hasCheckDirective = hasCheckDirective;
+            sourceFile.checkJsDirective = checkJsDirective;
         }
 
         function setExternalModuleIndicator(sourceFile: SourceFile) {

src/compiler/program.ts

@@ -904,10 +904,9 @@ namespace ts {
 
                 Debug.assert(!!sourceFile.bindDiagnostics);
                 const bindDiagnostics = sourceFile.bindDiagnostics;
-                // For JavaScript files, we don't want to report semantic errors.
-                // Instead, we'll report errors for using TypeScript-only constructs from within a
-                // JavaScript file when we get syntactic diagnostics for the file.
-                const includeCheckDiagnostics = options.checkJsFiles || sourceFile.hasCheckDirective || !isSourceFileJavaScript(sourceFile);
+                // For JavaScript files, we don't want to report semantic errors unless ecplicitlly requested.
+                const includeCheckDiagnostics = !isSourceFileJavaScript(sourceFile) ||
+                    (sourceFile.checkJsDirective ? sourceFile.checkJsDirective.enabled : options.checkJsFiles);
                 const checkDiagnostics = includeCheckDiagnostics ? typeChecker.getDiagnostics(sourceFile, cancellationToken) : [];
                 const fileProcessingDiagnosticsInFile = fileProcessingDiagnostics.getDiagnostics(sourceFile.fileName);
                 const programDiagnosticsInFile = programDiagnostics.getDiagnostics(sourceFile.fileName);

src/compiler/types.ts

@@ -1940,6 +1940,10 @@
         fileName: string;
     }
 
+    export interface CheckJsDirective extends TextRange {
+        enabled: boolean;
+    }
+
     export type CommentKind = SyntaxKind.SingleLineCommentTrivia | SyntaxKind.MultiLineCommentTrivia;
 
     export interface CommentRange extends TextRange {
@@ -2272,7 +2276,7 @@
         /* @internal */ moduleAugmentations: LiteralExpression[];
         /* @internal */ patternAmbientModules?: PatternAmbientModule[];
         /* @internal */ ambientModuleNames: string[];
-        /* @internal */ hasCheckDirective: boolean;
+        /* @internal */ checkJsDirective: CheckJsDirective | undefined;
     }
 
     export interface Bundle extends Node {

src/harness/harness.ts

@@ -202,7 +202,7 @@ namespace Utils {
             for (const childName in node) {
                 if (childName === "parent" || childName === "nextContainer" || childName === "modifiers" || childName === "externalModuleIndicator" ||
                     // for now ignore jsdoc comments
-                    childName === "jsDocComment") {
+                    childName === "jsDocComment" || childName === "checkJsDirective") {
                     continue;
                 }
                 const child = (<any>node)[childName];

src/services/services.ts

@@ -473,7 +473,7 @@ namespace ts {
         public moduleAugmentations: LiteralExpression[];
         private namedDeclarations: Map<Declaration[]>;
         public ambientModuleNames: string[];
-        public hasCheckDirective: boolean;
+        public checkJsDirective: CheckJsDirective | undefined;
 
         constructor(kind: SyntaxKind, pos: number, end: number) {
             super(kind, pos, end);

tests/baselines/reference/checkJsFiles4.errors.txt

@@ -0,0 +1,10 @@
+tests/cases/compiler/a.js(4,1): error TS2322: Type '0' is not assignable to type 'string'.
+
+
+==== tests/cases/compiler/a.js (1 errors) ====
+    
+    // @check true
+    var x = "string";
+    x = 0;
+    ~
+!!! error TS2322: Type '0' is not assignable to type 'string'.

tests/baselines/reference/checkJsFiles5.symbols

@@ -0,0 +1,9 @@
+=== tests/cases/compiler/a.js ===
+
+// @check false
+var x = "string";
+>x : Symbol(x, Decl(a.js, 2, 3))
+
+x = 0;
+>x : Symbol(x, Decl(a.js, 2, 3))
+

tests/baselines/reference/checkJsFiles5.types

@@ -0,0 +1,12 @@
+=== tests/cases/compiler/a.js ===
+
+// @check false
+var x = "string";
+>x : string
+>"string" : "string"
+
+x = 0;
+>x = 0 : 0
+>x : string
+>0 : 0
+

tests/cases/compiler/checkJsFiles4.ts

@@ -0,0 +1,8 @@
+// @allowJs: true
+// @checkJsFiles: false
+// @noEmit: true
+
+// @fileName: a.js
+// @check true
+var x = "string";
+x = 0;

tests/cases/compiler/checkJsFiles5.ts

@@ -0,0 +1,8 @@
+// @allowJs: true
+// @checkJsFiles: true
+// @noEmit: true
+
+// @fileName: a.js
+// @check false
+var x = "string";
+x = 0;