From 4257c2fa040b0c3787c392d76de52f8dcd868716 Mon Sep 17 00:00:00 2001
From: Sheetal Nandi <shkamat@microsoft.com>
Date: Fri, 23 Feb 2018 15:08:18 -0800
Subject: [PATCH] Resolve the .json file only if module name contains the
 extension

---
 src/compiler/checker.ts                       |  2 +-
 src/compiler/commandLineParser.ts             |  3 +-
 src/compiler/core.ts                          | 25 +++-----
 src/compiler/moduleNameResolver.ts            |  7 ++-
 src/compiler/program.ts                       |  4 +-
 src/harness/fourslash.ts                      |  3 +-
 .../unittests/reuseProgramStructure.ts        |  2 -
 src/services/jsTyping.ts                      |  4 +-
 ...sFileCompilationWithMapFileAsJs.errors.txt |  4 +-
 ...hMapFileAsJsWithInlineSourceMap.errors.txt |  4 +-
 ...lutionWithExtensions_unexpected.trace.json |  3 -
 ...utionWithExtensions_unexpected2.trace.json |  2 -
 .../packageJsonMain_isNonRecursive.trace.json |  4 --
 .../baselines/reference/requireOfJsonFile.js  |  4 +-
 .../reference/requireOfJsonFile.symbols       |  2 +-
 .../reference/requireOfJsonFile.types         |  2 +-
 .../reference/requireOfJsonFileNonRelative.js | 33 +++++++++++
 .../requireOfJsonFileNonRelative.symbols      | 47 +++++++++++++++
 .../requireOfJsonFileNonRelative.types        | 58 +++++++++++++++++++
 ...FileNonRelativeWithoutExtension.errors.txt | 29 ++++++++++
 ...reOfJsonFileNonRelativeWithoutExtension.js | 27 +++++++++
 ...sonFileNonRelativeWithoutExtension.symbols |  7 +++
 ...fJsonFileNonRelativeWithoutExtension.types |  7 +++
 ...NonRelativeWithoutExtensionResolvesToTs.js | 23 ++++++++
 ...lativeWithoutExtensionResolvesToTs.symbols | 11 ++++
 ...RelativeWithoutExtensionResolvesToTs.types | 11 ++++
 .../requireOfJsonFileWithEmptyObject.js       |  4 +-
 .../requireOfJsonFileWithEmptyObject.symbols  |  2 +-
 .../requireOfJsonFileWithEmptyObject.types    |  2 +-
 ...onFileWithEmptyObjectWithErrors.errors.txt |  2 +-
 ...uireOfJsonFileWithEmptyObjectWithErrors.js |  4 +-
 ...fJsonFileWithEmptyObjectWithErrors.symbols |  2 +-
 ...eOfJsonFileWithEmptyObjectWithErrors.types |  2 +-
 .../requireOfJsonFileWithNoContent.errors.txt |  2 +-
 .../requireOfJsonFileWithNoContent.js         |  4 +-
 .../requireOfJsonFileWithNoContent.symbols    |  2 +-
 .../requireOfJsonFileWithNoContent.types      |  2 +-
 .../requireOfJsonFileWithoutAllowJs.js        |  9 ++-
 .../requireOfJsonFileWithoutAllowJs.symbols   | 16 ++++-
 .../requireOfJsonFileWithoutAllowJs.types     | 46 +++++++++------
 ...quireOfJsonFileWithoutExtension.errors.txt | 19 ++++++
 .../requireOfJsonFileWithoutExtension.js      | 32 ++++++++++
 .../requireOfJsonFileWithoutExtension.symbols | 34 +++++++++++
 .../requireOfJsonFileWithoutExtension.types   | 45 ++++++++++++++
 ...eOfJsonFileWithoutExtensionResolvesToTs.js | 44 ++++++++++++++
 ...onFileWithoutExtensionResolvesToTs.symbols | 44 ++++++++++++++
 ...JsonFileWithoutExtensionResolvesToTs.types | 53 +++++++++++++++++
 ...mMultipleNodeModulesDirectories.trace.json |  6 --
 ...romNodeModulesInParentDirectory.trace.json |  1 -
 tests/cases/compiler/requireOfJsonFile.ts     |  2 +-
 .../compiler/requireOfJsonFileNonRelative.ts  | 24 ++++++++
 ...reOfJsonFileNonRelativeWithoutExtension.ts | 25 ++++++++
 ...NonRelativeWithoutExtensionResolvesToTs.ts | 16 +++++
 .../requireOfJsonFileWithEmptyObject.ts       |  2 +-
 ...uireOfJsonFileWithEmptyObjectWithErrors.ts |  2 +-
 .../requireOfJsonFileWithNoContent.ts         |  2 +-
 .../requireOfJsonFileWithoutAllowJs.ts        |  2 +-
 .../requireOfJsonFileWithoutExtension.ts      | 18 ++++++
 ...eOfJsonFileWithoutExtensionResolvesToTs.ts | 27 +++++++++
 59 files changed, 733 insertions(+), 92 deletions(-)
 create mode 100644 tests/baselines/reference/requireOfJsonFileNonRelative.js
 create mode 100644 tests/baselines/reference/requireOfJsonFileNonRelative.symbols
 create mode 100644 tests/baselines/reference/requireOfJsonFileNonRelative.types
 create mode 100644 tests/baselines/reference/requireOfJsonFileNonRelativeWithoutExtension.errors.txt
 create mode 100644 tests/baselines/reference/requireOfJsonFileNonRelativeWithoutExtension.js
 create mode 100644 tests/baselines/reference/requireOfJsonFileNonRelativeWithoutExtension.symbols
 create mode 100644 tests/baselines/reference/requireOfJsonFileNonRelativeWithoutExtension.types
 create mode 100644 tests/baselines/reference/requireOfJsonFileNonRelativeWithoutExtensionResolvesToTs.js
 create mode 100644 tests/baselines/reference/requireOfJsonFileNonRelativeWithoutExtensionResolvesToTs.symbols
 create mode 100644 tests/baselines/reference/requireOfJsonFileNonRelativeWithoutExtensionResolvesToTs.types
 create mode 100644 tests/baselines/reference/requireOfJsonFileWithoutExtension.errors.txt
 create mode 100644 tests/baselines/reference/requireOfJsonFileWithoutExtension.js
 create mode 100644 tests/baselines/reference/requireOfJsonFileWithoutExtension.symbols
 create mode 100644 tests/baselines/reference/requireOfJsonFileWithoutExtension.types
 create mode 100644 tests/baselines/reference/requireOfJsonFileWithoutExtensionResolvesToTs.js
 create mode 100644 tests/baselines/reference/requireOfJsonFileWithoutExtensionResolvesToTs.symbols
 create mode 100644 tests/baselines/reference/requireOfJsonFileWithoutExtensionResolvesToTs.types
 create mode 100644 tests/cases/compiler/requireOfJsonFileNonRelative.ts
 create mode 100644 tests/cases/compiler/requireOfJsonFileNonRelativeWithoutExtension.ts
 create mode 100644 tests/cases/compiler/requireOfJsonFileNonRelativeWithoutExtensionResolvesToTs.ts
 create mode 100644 tests/cases/compiler/requireOfJsonFileWithoutExtension.ts
 create mode 100644 tests/cases/compiler/requireOfJsonFileWithoutExtensionResolvesToTs.ts

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 5772e1a2241..977dcc7a8fc 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -2084,7 +2084,7 @@ namespace ts {
             }
 
             // May be an untyped module. If so, ignore resolutionDiagnostic.
-            if (resolvedModule && !extensionIsTypeScript(resolvedModule.extension) && resolutionDiagnostic === undefined || resolutionDiagnostic === Diagnostics.Could_not_find_a_declaration_file_for_module_0_1_implicitly_has_an_any_type) {
+            if (resolvedModule && !resolutionExtensionIsTypeScriptOrJson(resolvedModule.extension) && resolutionDiagnostic === undefined || resolutionDiagnostic === Diagnostics.Could_not_find_a_declaration_file_for_module_0_1_implicitly_has_an_any_type) {
                 if (isForAugmentation) {
                     const diag = Diagnostics.Invalid_module_name_in_augmentation_Module_0_resolves_to_an_untyped_module_at_1_which_cannot_be_augmented;
                     error(errorNode, diag, moduleReference, resolvedModule.resolvedFileName);
diff --git a/src/compiler/commandLineParser.ts b/src/compiler/commandLineParser.ts
index c8e7bf8d19f..eddf40cc94b 100644
--- a/src/compiler/commandLineParser.ts
+++ b/src/compiler/commandLineParser.ts
@@ -2044,8 +2044,7 @@ namespace ts {
 
         // Rather than requery this for each file and filespec, we query the supported extensions
         // once and store it on the expansion context.
-        // When computing file names, do not include json files. Use only module resolution or explicit includes for them
-        const supportedExtensions = getSupportedExtensions(options, extraFileExtensions, /*excludeJson*/ true);
+        const supportedExtensions = getSupportedExtensions(options, extraFileExtensions);
 
         // Literal files are always included verbatim. An "include" or "exclude" specification cannot
         // remove a literal file.
diff --git a/src/compiler/core.ts b/src/compiler/core.ts
index 52358737dcf..00a28dbbbcd 100644
--- a/src/compiler/core.ts
+++ b/src/compiler/core.ts
@@ -2674,21 +2674,14 @@ namespace ts {
     export const supportedTypescriptExtensionsForExtractExtension: ReadonlyArray<Extension> = [Extension.Dts, Extension.Ts, Extension.Tsx];
     export const supportedJavascriptExtensions: ReadonlyArray<Extension> = [Extension.Js, Extension.Jsx];
     const allSupportedExtensions: ReadonlyArray<Extension> = [...supportedTypeScriptExtensions, ...supportedJavascriptExtensions];
-    let allSupportedExtensionsIncludingJson: ReadonlyArray<Extension> | undefined;
-    function getAllSupportedExtensionsIncludingJson() {
-        return allSupportedExtensionsIncludingJson || (allSupportedExtensionsIncludingJson = [...allSupportedExtensions, Extension.Json]);
-    }
 
-    export function getSupportedExtensions(options?: CompilerOptions, extraFileExtensions?: ReadonlyArray<JsFileExtensionInfo>, excludeJson?: boolean): ReadonlyArray<string> {
+    export function getSupportedExtensions(options?: CompilerOptions, extraFileExtensions?: ReadonlyArray<JsFileExtensionInfo>): ReadonlyArray<string> {
         const needAllExtensions = options && options.allowJs;
-        const useJsonExtension = needAllExtensions && !excludeJson && getEmitModuleResolutionKind(options) === ModuleResolutionKind.NodeJs;
         if (!extraFileExtensions || extraFileExtensions.length === 0 || !needAllExtensions) {
-            return useJsonExtension ?
-                getAllSupportedExtensionsIncludingJson() :
-                needAllExtensions ? allSupportedExtensions : supportedTypeScriptExtensions;
+            return needAllExtensions ? allSupportedExtensions : supportedTypeScriptExtensions;
         }
         return deduplicate(
-            [...(useJsonExtension ? getAllSupportedExtensionsIncludingJson() : allSupportedExtensions), ...extraFileExtensions.map(e => e.extension)],
+            [...allSupportedExtensions, ...extraFileExtensions.map(e => e.extension)],
             equateStringsCaseSensitive,
             compareStringsCaseSensitive
         );
@@ -2698,10 +2691,6 @@ namespace ts {
         return forEach(supportedJavascriptExtensions, extension => fileExtensionIs(fileName, extension));
     }
 
-    export function hasJavaScriptOrJsonFileExtension(fileName: string) {
-        return hasJavaScriptFileExtension(fileName) || fileExtensionIs(fileName, Extension.Json);
-    }
-
     export function hasTypeScriptFileExtension(fileName: string) {
         return forEach(supportedTypeScriptExtensions, extension => fileExtensionIs(fileName, extension));
     }
@@ -3102,6 +3091,10 @@ namespace ts {
         return ext === Extension.Ts || ext === Extension.Tsx || ext === Extension.Dts;
     }
 
+    export function resolutionExtensionIsTypeScriptOrJson(ext: Extension) {
+        return extensionIsTypeScript(ext) || ext === Extension.Json;
+    }
+
     /**
      * Gets the extension from a path.
      * Path must have a valid extension.
@@ -3119,9 +3112,7 @@ namespace ts {
     }
 
     export function tryGetExtensionFromPath(path: string): Extension | undefined {
-        return find<Extension>(supportedTypescriptExtensionsForExtractExtension, e => fileExtensionIs(path, e)) ||
-            find(supportedJavascriptExtensions, e => fileExtensionIs(path, e)) ||
-            (fileExtensionIs(path, Extension.Json) ? Extension.Json : undefined);
+        return find<Extension>(supportedTypescriptExtensionsForExtractExtension, e => fileExtensionIs(path, e)) || find(supportedJavascriptExtensions, e => fileExtensionIs(path, e));
     }
 
     // Retrieves any string from the final "." onwards from a base file name.
diff --git a/src/compiler/moduleNameResolver.ts b/src/compiler/moduleNameResolver.ts
index f1d97b68404..7f2578e16df 100644
--- a/src/compiler/moduleNameResolver.ts
+++ b/src/compiler/moduleNameResolver.ts
@@ -882,6 +882,11 @@ namespace ts {
      * in cases when we know upfront that all load attempts will fail (because containing folder does not exists) however we still need to record all failed lookup locations.
      */
     function loadModuleFromFile(extensions: Extensions, candidate: string, failedLookupLocations: Push<string>, onlyRecordFailures: boolean, state: ModuleResolutionState): PathAndExtension | undefined {
+        if (extensions === Extensions.Json) {
+            const extensionLess = tryRemoveExtension(candidate, Extension.Json);
+            return extensionLess && tryAddingExtensions(extensionLess, extensions, failedLookupLocations, onlyRecordFailures, state);
+        }
+
         // First, try adding an extension. An import of "foo" could be matched by a file "foo.ts", or "foo.js" by "foo.js.ts"
         const resolvedByAddingExtension = tryAddingExtensions(candidate, extensions, failedLookupLocations, onlyRecordFailures, state);
         if (resolvedByAddingExtension) {
@@ -890,7 +895,7 @@ namespace ts {
 
         // If that didn't work, try stripping a ".js" or ".jsx" extension and replacing it with a TypeScript one;
         // e.g. "./foo.js" can be matched by "./foo.ts" or "./foo.d.ts"
-        if (hasJavaScriptOrJsonFileExtension(candidate)) {
+        if (hasJavaScriptFileExtension(candidate)) {
             const extensionless = removeFileExtension(candidate);
             if (state.traceEnabled) {
                 const extension = candidate.substring(extensionless.length);
diff --git a/src/compiler/program.ts b/src/compiler/program.ts
index 362aa258bb8..d5664e98fce 100644
--- a/src/compiler/program.ts
+++ b/src/compiler/program.ts
@@ -1975,7 +1975,7 @@ namespace ts {
                     }
 
                     const isFromNodeModulesSearch = resolution.isExternalLibraryImport;
-                    const isJsFile = !extensionIsTypeScript(resolution.extension);
+                    const isJsFile = !resolutionExtensionIsTypeScriptOrJson(resolution.extension);
                     const isJsFileFromNodeModules = isFromNodeModulesSearch && isJsFile;
                     const resolvedFileName = resolution.resolvedFileName;
 
@@ -2405,6 +2405,7 @@ namespace ts {
         switch (extension) {
             case Extension.Ts:
             case Extension.Dts:
+            case Extension.Json:
                 // These are always allowed.
                 return undefined;
             case Extension.Tsx:
@@ -2412,7 +2413,6 @@ namespace ts {
             case Extension.Jsx:
                 return needJsx() || needAllowJs();
             case Extension.Js:
-            case Extension.Json:
                 return needAllowJs();
         }
 
diff --git a/src/harness/fourslash.ts b/src/harness/fourslash.ts
index 1b849f36b3a..7fdbbbc9640 100644
--- a/src/harness/fourslash.ts
+++ b/src/harness/fourslash.ts
@@ -511,9 +511,8 @@ namespace FourSlash {
         }
 
         private getAllDiagnostics(): ts.Diagnostic[] {
-            const options = this.languageService.getProgram().getCompilerOptions();
             return ts.flatMap(this.languageServiceAdapterHost.getFilenames(), fileName =>
-                ts.fileExtensionIsOneOf(fileName, ts.getSupportedExtensions(options)) ? this.getDiagnostics(fileName) : []);
+                ts.isAnySupportedFileExtension(fileName) ? this.getDiagnostics(fileName) : []);
         }
 
         public verifyErrorExistsAfterMarker(markerName: string, shouldExist: boolean, after: boolean) {
diff --git a/src/harness/unittests/reuseProgramStructure.ts b/src/harness/unittests/reuseProgramStructure.ts
index c43fe2f5528..72528e7c71b 100644
--- a/src/harness/unittests/reuseProgramStructure.ts
+++ b/src/harness/unittests/reuseProgramStructure.ts
@@ -473,8 +473,6 @@ namespace ts {
                         "File 'node_modules/a/index.jsx' does not exist.",
                         "Loading module 'a' from 'node_modules' folder, target file type 'Json'.",
                         "File 'node_modules/a/package.json' does not exist.",
-                        "File 'node_modules/a.json' does not exist.",
-                        "File 'node_modules/a/index.json' does not exist.",
                         "======== Module name 'a' was not resolved. ========"
                     ],
                     "initialProgram: execute module resolution normally.");
diff --git a/src/services/jsTyping.ts b/src/services/jsTyping.ts
index a32be9802c2..bd6c2e5cb9f 100644
--- a/src/services/jsTyping.ts
+++ b/src/services/jsTyping.ts
@@ -98,7 +98,7 @@ namespace ts.JsTyping {
         // Only infer typings for .js and .jsx files
         fileNames = mapDefined(fileNames, fileName => {
             const path = normalizePath(fileName);
-            if (hasJavaScriptOrJsonFileExtension(path)) {
+            if (hasJavaScriptFileExtension(path)) {
                 return path;
             }
         });
@@ -193,7 +193,7 @@ namespace ts.JsTyping {
          */
         function getTypingNamesFromSourceFileNames(fileNames: string[]) {
             const fromFileNames = mapDefined(fileNames, j => {
-                if (!hasJavaScriptOrJsonFileExtension(j)) return undefined;
+                if (!hasJavaScriptFileExtension(j)) return undefined;
 
                 const inferredTypingName = removeFileExtension(getBaseFileName(j.toLowerCase()));
                 const cleanedTypingName = removeMinAndVersionNumbers(inferredTypingName);
diff --git a/tests/baselines/reference/jsFileCompilationWithMapFileAsJs.errors.txt b/tests/baselines/reference/jsFileCompilationWithMapFileAsJs.errors.txt
index 5e0ff050c12..f9d88bd2727 100644
--- a/tests/baselines/reference/jsFileCompilationWithMapFileAsJs.errors.txt
+++ b/tests/baselines/reference/jsFileCompilationWithMapFileAsJs.errors.txt
@@ -1,11 +1,11 @@
 error TS5055: Cannot write file 'tests/cases/compiler/b.js' because it would overwrite input file.
   Adding a tsconfig.json file will help organize projects that contain both TypeScript and JavaScript files. Learn more at https://aka.ms/tsconfig.
-error TS6054: File 'tests/cases/compiler/b.js.map' has unsupported extension. The only supported extensions are '.ts', '.tsx', '.d.ts', '.js', '.jsx', '.json'.
+error TS6054: File 'tests/cases/compiler/b.js.map' has unsupported extension. The only supported extensions are '.ts', '.tsx', '.d.ts', '.js', '.jsx'.
 
 
 !!! error TS5055: Cannot write file 'tests/cases/compiler/b.js' because it would overwrite input file.
 !!! error TS5055:   Adding a tsconfig.json file will help organize projects that contain both TypeScript and JavaScript files. Learn more at https://aka.ms/tsconfig.
-!!! error TS6054: File 'tests/cases/compiler/b.js.map' has unsupported extension. The only supported extensions are '.ts', '.tsx', '.d.ts', '.js', '.jsx', '.json'.
+!!! error TS6054: File 'tests/cases/compiler/b.js.map' has unsupported extension. The only supported extensions are '.ts', '.tsx', '.d.ts', '.js', '.jsx'.
 ==== tests/cases/compiler/a.ts (0 errors) ====
     class c {
     }
diff --git a/tests/baselines/reference/jsFileCompilationWithMapFileAsJsWithInlineSourceMap.errors.txt b/tests/baselines/reference/jsFileCompilationWithMapFileAsJsWithInlineSourceMap.errors.txt
index 5e0ff050c12..f9d88bd2727 100644
--- a/tests/baselines/reference/jsFileCompilationWithMapFileAsJsWithInlineSourceMap.errors.txt
+++ b/tests/baselines/reference/jsFileCompilationWithMapFileAsJsWithInlineSourceMap.errors.txt
@@ -1,11 +1,11 @@
 error TS5055: Cannot write file 'tests/cases/compiler/b.js' because it would overwrite input file.
   Adding a tsconfig.json file will help organize projects that contain both TypeScript and JavaScript files. Learn more at https://aka.ms/tsconfig.
-error TS6054: File 'tests/cases/compiler/b.js.map' has unsupported extension. The only supported extensions are '.ts', '.tsx', '.d.ts', '.js', '.jsx', '.json'.
+error TS6054: File 'tests/cases/compiler/b.js.map' has unsupported extension. The only supported extensions are '.ts', '.tsx', '.d.ts', '.js', '.jsx'.
 
 
 !!! error TS5055: Cannot write file 'tests/cases/compiler/b.js' because it would overwrite input file.
 !!! error TS5055:   Adding a tsconfig.json file will help organize projects that contain both TypeScript and JavaScript files. Learn more at https://aka.ms/tsconfig.
-!!! error TS6054: File 'tests/cases/compiler/b.js.map' has unsupported extension. The only supported extensions are '.ts', '.tsx', '.d.ts', '.js', '.jsx', '.json'.
+!!! error TS6054: File 'tests/cases/compiler/b.js.map' has unsupported extension. The only supported extensions are '.ts', '.tsx', '.d.ts', '.js', '.jsx'.
 ==== tests/cases/compiler/a.ts (0 errors) ====
     class c {
     }
diff --git a/tests/baselines/reference/moduleResolutionWithExtensions_unexpected.trace.json b/tests/baselines/reference/moduleResolutionWithExtensions_unexpected.trace.json
index f2cbd45826d..b5d62eb0a25 100644
--- a/tests/baselines/reference/moduleResolutionWithExtensions_unexpected.trace.json
+++ b/tests/baselines/reference/moduleResolutionWithExtensions_unexpected.trace.json
@@ -36,13 +36,10 @@
     "'package.json' does not have a 'types' field.",
     "'package.json' has 'main' field 'normalize.css' that references '/node_modules/normalize.css/normalize.css'.",
     "Found 'package.json' at '/node_modules/normalize.css/package.json'.",
-    "File '/node_modules/normalize.css.json' does not exist.",
     "'package.json' has 'main' field 'normalize.css' that references '/node_modules/normalize.css/normalize.css'.",
     "File '/node_modules/normalize.css/normalize.css' exist - use it as a name resolution result.",
     "File '/node_modules/normalize.css/normalize.css' has an unsupported extension, so skipping it.",
     "Loading module as file / folder, candidate module location '/node_modules/normalize.css/normalize.css', target file type 'Json'.",
-    "File '/node_modules/normalize.css/normalize.css.json' does not exist.",
     "Directory '/node_modules/normalize.css/normalize.css' does not exist, skipping all lookups in it.",
-    "File '/node_modules/normalize.css/index.json' does not exist.",
     "======== Module name 'normalize.css' was not resolved. ========"
 ]
\ No newline at end of file
diff --git a/tests/baselines/reference/moduleResolutionWithExtensions_unexpected2.trace.json b/tests/baselines/reference/moduleResolutionWithExtensions_unexpected2.trace.json
index 3dd0a7861e3..36ef8252cc7 100644
--- a/tests/baselines/reference/moduleResolutionWithExtensions_unexpected2.trace.json
+++ b/tests/baselines/reference/moduleResolutionWithExtensions_unexpected2.trace.json
@@ -38,8 +38,6 @@
     "'package.json' does not have a 'typings' field.",
     "'package.json' has 'types' field 'foo.js' that references '/node_modules/foo/foo.js'.",
     "Found 'package.json' at '/node_modules/foo/package.json'.",
-    "File '/node_modules/foo.json' does not exist.",
     "'package.json' does not have a 'main' field.",
-    "File '/node_modules/foo/index.json' does not exist.",
     "======== Module name 'foo' was not resolved. ========"
 ]
\ No newline at end of file
diff --git a/tests/baselines/reference/packageJsonMain_isNonRecursive.trace.json b/tests/baselines/reference/packageJsonMain_isNonRecursive.trace.json
index 653f224b43a..2ee886f24c7 100644
--- a/tests/baselines/reference/packageJsonMain_isNonRecursive.trace.json
+++ b/tests/baselines/reference/packageJsonMain_isNonRecursive.trace.json
@@ -36,12 +36,8 @@
     "'package.json' does not have a 'types' field.",
     "'package.json' has 'main' field 'oof' that references '/node_modules/foo/oof'.",
     "Found 'package.json' at '/node_modules/foo/package.json'.",
-    "File '/node_modules/foo.json' does not exist.",
     "'package.json' has 'main' field 'oof' that references '/node_modules/foo/oof'.",
     "File '/node_modules/foo/oof' does not exist.",
     "Loading module as file / folder, candidate module location '/node_modules/foo/oof', target file type 'Json'.",
-    "File '/node_modules/foo/oof.json' does not exist.",
-    "File '/node_modules/foo/oof/index.json' does not exist.",
-    "File '/node_modules/foo/index.json' does not exist.",
     "======== Module name 'foo' was not resolved. ========"
 ]
\ No newline at end of file
diff --git a/tests/baselines/reference/requireOfJsonFile.js b/tests/baselines/reference/requireOfJsonFile.js
index 6d6498bf020..ee6cf710045 100644
--- a/tests/baselines/reference/requireOfJsonFile.js
+++ b/tests/baselines/reference/requireOfJsonFile.js
@@ -1,7 +1,7 @@
 //// [tests/cases/compiler/requireOfJsonFile.ts] ////
 
 //// [file1.ts]
-import b1 = require('./b');
+import b1 = require('./b.json');
 let x = b1.a;
 import b2 = require('./b.json');
 if (x) {
@@ -23,7 +23,7 @@ if (x) {
 //// [file1.js]
 "use strict";
 exports.__esModule = true;
-var b1 = require("./b");
+var b1 = require("./b.json");
 var x = b1.a;
 var b2 = require("./b.json");
 if (x) {
diff --git a/tests/baselines/reference/requireOfJsonFile.symbols b/tests/baselines/reference/requireOfJsonFile.symbols
index 803c02e016a..a8f82b6b145 100644
--- a/tests/baselines/reference/requireOfJsonFile.symbols
+++ b/tests/baselines/reference/requireOfJsonFile.symbols
@@ -1,5 +1,5 @@
 === tests/cases/compiler/file1.ts ===
-import b1 = require('./b');
+import b1 = require('./b.json');
 >b1 : Symbol(b1, Decl(file1.ts, 0, 0))
 
 let x = b1.a;
diff --git a/tests/baselines/reference/requireOfJsonFile.types b/tests/baselines/reference/requireOfJsonFile.types
index 7911e2eb1ab..c718c429408 100644
--- a/tests/baselines/reference/requireOfJsonFile.types
+++ b/tests/baselines/reference/requireOfJsonFile.types
@@ -1,5 +1,5 @@
 === tests/cases/compiler/file1.ts ===
-import b1 = require('./b');
+import b1 = require('./b.json');
 >b1 : { "a": boolean; "b": string; }
 
 let x = b1.a;
diff --git a/tests/baselines/reference/requireOfJsonFileNonRelative.js b/tests/baselines/reference/requireOfJsonFileNonRelative.js
new file mode 100644
index 00000000000..0b78328c707
--- /dev/null
+++ b/tests/baselines/reference/requireOfJsonFileNonRelative.js
@@ -0,0 +1,33 @@
+//// [tests/cases/compiler/requireOfJsonFileNonRelative.ts] ////
+
+//// [file1.ts]
+import b1 = require('b.json');
+let x = b1.a;
+import b2 = require('c.json');
+if (x) {
+    let b = b2.b;
+    x = (b1.b === b);
+}
+
+//// [b.json]
+{
+    "a": true,
+    "b": "hello"
+}
+
+//// [c.json]
+{
+    "a": true,
+    "b": "hello"
+}
+
+//// [file1.js]
+"use strict";
+exports.__esModule = true;
+var b1 = require("b.json");
+var x = b1.a;
+var b2 = require("c.json");
+if (x) {
+    var b = b2.b;
+    x = (b1.b === b);
+}
diff --git a/tests/baselines/reference/requireOfJsonFileNonRelative.symbols b/tests/baselines/reference/requireOfJsonFileNonRelative.symbols
new file mode 100644
index 00000000000..4a381206204
--- /dev/null
+++ b/tests/baselines/reference/requireOfJsonFileNonRelative.symbols
@@ -0,0 +1,47 @@
+=== /src/projects/file1.ts ===
+import b1 = require('b.json');
+>b1 : Symbol(b1, Decl(file1.ts, 0, 0))
+
+let x = b1.a;
+>x : Symbol(x, Decl(file1.ts, 1, 3))
+>b1.a : Symbol("a", Decl(b.json, 0, 1))
+>b1 : Symbol(b1, Decl(file1.ts, 0, 0))
+>a : Symbol("a", Decl(b.json, 0, 1))
+
+import b2 = require('c.json');
+>b2 : Symbol(b2, Decl(file1.ts, 1, 13))
+
+if (x) {
+>x : Symbol(x, Decl(file1.ts, 1, 3))
+
+    let b = b2.b;
+>b : Symbol(b, Decl(file1.ts, 4, 7))
+>b2.b : Symbol("b", Decl(c.json, 1, 14))
+>b2 : Symbol(b2, Decl(file1.ts, 1, 13))
+>b : Symbol("b", Decl(c.json, 1, 14))
+
+    x = (b1.b === b);
+>x : Symbol(x, Decl(file1.ts, 1, 3))
+>b1.b : Symbol("b", Decl(b.json, 1, 14))
+>b1 : Symbol(b1, Decl(file1.ts, 0, 0))
+>b : Symbol("b", Decl(b.json, 1, 14))
+>b : Symbol(b, Decl(file1.ts, 4, 7))
+}
+
+=== /src/projects/node_modules/b.json ===
+{
+    "a": true,
+>"a" : Symbol("a", Decl(b.json, 0, 1))
+
+    "b": "hello"
+>"b" : Symbol("b", Decl(b.json, 1, 14))
+}
+
+=== /src/node_modules/c.json ===
+{
+    "a": true,
+>"a" : Symbol("a", Decl(c.json, 0, 1))
+
+    "b": "hello"
+>"b" : Symbol("b", Decl(c.json, 1, 14))
+}
diff --git a/tests/baselines/reference/requireOfJsonFileNonRelative.types b/tests/baselines/reference/requireOfJsonFileNonRelative.types
new file mode 100644
index 00000000000..8f15e2282d9
--- /dev/null
+++ b/tests/baselines/reference/requireOfJsonFileNonRelative.types
@@ -0,0 +1,58 @@
+=== /src/projects/file1.ts ===
+import b1 = require('b.json');
+>b1 : { "a": boolean; "b": string; }
+
+let x = b1.a;
+>x : boolean
+>b1.a : boolean
+>b1 : { "a": boolean; "b": string; }
+>a : boolean
+
+import b2 = require('c.json');
+>b2 : { "a": boolean; "b": string; }
+
+if (x) {
+>x : boolean
+
+    let b = b2.b;
+>b : string
+>b2.b : string
+>b2 : { "a": boolean; "b": string; }
+>b : string
+
+    x = (b1.b === b);
+>x = (b1.b === b) : boolean
+>x : boolean
+>(b1.b === b) : boolean
+>b1.b === b : boolean
+>b1.b : string
+>b1 : { "a": boolean; "b": string; }
+>b : string
+>b : string
+}
+
+=== /src/projects/node_modules/b.json ===
+{
+>{    "a": true,    "b": "hello"} : { "a": boolean; "b": string; }
+
+    "a": true,
+>"a" : boolean
+>true : true
+
+    "b": "hello"
+>"b" : string
+>"hello" : "hello"
+}
+
+=== /src/node_modules/c.json ===
+{
+>{    "a": true,    "b": "hello"} : { "a": boolean; "b": string; }
+
+    "a": true,
+>"a" : boolean
+>true : true
+
+    "b": "hello"
+>"b" : string
+>"hello" : "hello"
+}
diff --git a/tests/baselines/reference/requireOfJsonFileNonRelativeWithoutExtension.errors.txt b/tests/baselines/reference/requireOfJsonFileNonRelativeWithoutExtension.errors.txt
new file mode 100644
index 00000000000..13660f8b836
--- /dev/null
+++ b/tests/baselines/reference/requireOfJsonFileNonRelativeWithoutExtension.errors.txt
@@ -0,0 +1,29 @@
+/src/projects/file1.ts(1,20): error TS2307: Cannot find module 'd.json'.
+/src/projects/file1.ts(2,20): error TS2307: Cannot find module 'e'.
+
+
+==== /src/projects/file1.ts (2 errors) ====
+    import d = require("d.json"); // Should fail
+                       ~~~~~~~~
+!!! error TS2307: Cannot find module 'd.json'.
+    import e = require("e"); // Should fail
+                       ~~~
+!!! error TS2307: Cannot find module 'e'.
+    
+==== /src/projects/node_modules/b.json (0 errors) ====
+    {
+        "a": true,
+        "b": "hello"
+    }
+    
+==== /src/projects/node_modules/e.json (0 errors) ====
+    {
+        "a": true,
+        "b": "hello"
+    }
+    
+==== /src/node_modules/c.json (0 errors) ====
+    {
+        "a": true,
+        "b": "hello"
+    }
\ No newline at end of file
diff --git a/tests/baselines/reference/requireOfJsonFileNonRelativeWithoutExtension.js b/tests/baselines/reference/requireOfJsonFileNonRelativeWithoutExtension.js
new file mode 100644
index 00000000000..c476d43efc1
--- /dev/null
+++ b/tests/baselines/reference/requireOfJsonFileNonRelativeWithoutExtension.js
@@ -0,0 +1,27 @@
+//// [tests/cases/compiler/requireOfJsonFileNonRelativeWithoutExtension.ts] ////
+
+//// [file1.ts]
+import d = require("d.json"); // Should fail
+import e = require("e"); // Should fail
+
+//// [b.json]
+{
+    "a": true,
+    "b": "hello"
+}
+
+//// [e.json]
+{
+    "a": true,
+    "b": "hello"
+}
+
+//// [c.json]
+{
+    "a": true,
+    "b": "hello"
+}
+
+//// [file1.js]
+"use strict";
+exports.__esModule = true;
diff --git a/tests/baselines/reference/requireOfJsonFileNonRelativeWithoutExtension.symbols b/tests/baselines/reference/requireOfJsonFileNonRelativeWithoutExtension.symbols
new file mode 100644
index 00000000000..0eedb44c3dc
--- /dev/null
+++ b/tests/baselines/reference/requireOfJsonFileNonRelativeWithoutExtension.symbols
@@ -0,0 +1,7 @@
+=== /src/projects/file1.ts ===
+import d = require("d.json"); // Should fail
+>d : Symbol(d, Decl(file1.ts, 0, 0))
+
+import e = require("e"); // Should fail
+>e : Symbol(e, Decl(file1.ts, 0, 29))
+
diff --git a/tests/baselines/reference/requireOfJsonFileNonRelativeWithoutExtension.types b/tests/baselines/reference/requireOfJsonFileNonRelativeWithoutExtension.types
new file mode 100644
index 00000000000..ec891ba6280
--- /dev/null
+++ b/tests/baselines/reference/requireOfJsonFileNonRelativeWithoutExtension.types
@@ -0,0 +1,7 @@
+=== /src/projects/file1.ts ===
+import d = require("d.json"); // Should fail
+>d : any
+
+import e = require("e"); // Should fail
+>e : any
+
diff --git a/tests/baselines/reference/requireOfJsonFileNonRelativeWithoutExtensionResolvesToTs.js b/tests/baselines/reference/requireOfJsonFileNonRelativeWithoutExtensionResolvesToTs.js
new file mode 100644
index 00000000000..b4b8a449b2e
--- /dev/null
+++ b/tests/baselines/reference/requireOfJsonFileNonRelativeWithoutExtensionResolvesToTs.js
@@ -0,0 +1,23 @@
+//// [tests/cases/compiler/requireOfJsonFileNonRelativeWithoutExtensionResolvesToTs.ts] ////
+
+//// [file1.ts]
+import f = require("f"); // should work to f.ts
+let fnumber: number = f;
+
+//// [f.json]
+{
+    "a": true,
+    "b": "hello"
+}
+
+//// [f.ts]
+export = 10;
+
+//// [f.js]
+"use strict";
+module.exports = 10;
+//// [file1.js]
+"use strict";
+exports.__esModule = true;
+var f = require("f"); // should work to f.ts
+var fnumber = f;
diff --git a/tests/baselines/reference/requireOfJsonFileNonRelativeWithoutExtensionResolvesToTs.symbols b/tests/baselines/reference/requireOfJsonFileNonRelativeWithoutExtensionResolvesToTs.symbols
new file mode 100644
index 00000000000..cf903d2fcfb
--- /dev/null
+++ b/tests/baselines/reference/requireOfJsonFileNonRelativeWithoutExtensionResolvesToTs.symbols
@@ -0,0 +1,11 @@
+=== /src/projects/file1.ts ===
+import f = require("f"); // should work to f.ts
+>f : Symbol(f, Decl(file1.ts, 0, 0))
+
+let fnumber: number = f;
+>fnumber : Symbol(fnumber, Decl(file1.ts, 1, 3))
+>f : Symbol(f, Decl(file1.ts, 0, 0))
+
+=== /src/node_modules/f.ts ===
+export = 10;
+No type information for this code.
\ No newline at end of file
diff --git a/tests/baselines/reference/requireOfJsonFileNonRelativeWithoutExtensionResolvesToTs.types b/tests/baselines/reference/requireOfJsonFileNonRelativeWithoutExtensionResolvesToTs.types
new file mode 100644
index 00000000000..75c2db9bae9
--- /dev/null
+++ b/tests/baselines/reference/requireOfJsonFileNonRelativeWithoutExtensionResolvesToTs.types
@@ -0,0 +1,11 @@
+=== /src/projects/file1.ts ===
+import f = require("f"); // should work to f.ts
+>f : 10
+
+let fnumber: number = f;
+>fnumber : number
+>f : 10
+
+=== /src/node_modules/f.ts ===
+export = 10;
+No type information for this code.
\ No newline at end of file
diff --git a/tests/baselines/reference/requireOfJsonFileWithEmptyObject.js b/tests/baselines/reference/requireOfJsonFileWithEmptyObject.js
index 12c912195d4..851a914d30e 100644
--- a/tests/baselines/reference/requireOfJsonFileWithEmptyObject.js
+++ b/tests/baselines/reference/requireOfJsonFileWithEmptyObject.js
@@ -1,7 +1,7 @@
 //// [tests/cases/compiler/requireOfJsonFileWithEmptyObject.ts] ////
 
 //// [file1.ts]
-import b1 = require('./b');
+import b1 = require('./b.json');
 let x = b1;
 import b2 = require('./b.json');
 if (x) {
@@ -17,7 +17,7 @@ if (x) {
 //// [file1.js]
 "use strict";
 exports.__esModule = true;
-var b1 = require("./b");
+var b1 = require("./b.json");
 var x = b1;
 var b2 = require("./b.json");
 if (x) {
diff --git a/tests/baselines/reference/requireOfJsonFileWithEmptyObject.symbols b/tests/baselines/reference/requireOfJsonFileWithEmptyObject.symbols
index 4edf64ef720..84f4cc98c5b 100644
--- a/tests/baselines/reference/requireOfJsonFileWithEmptyObject.symbols
+++ b/tests/baselines/reference/requireOfJsonFileWithEmptyObject.symbols
@@ -1,5 +1,5 @@
 === tests/cases/compiler/file1.ts ===
-import b1 = require('./b');
+import b1 = require('./b.json');
 >b1 : Symbol(b1, Decl(file1.ts, 0, 0))
 
 let x = b1;
diff --git a/tests/baselines/reference/requireOfJsonFileWithEmptyObject.types b/tests/baselines/reference/requireOfJsonFileWithEmptyObject.types
index 6a8bad1793b..5cbc36a7e54 100644
--- a/tests/baselines/reference/requireOfJsonFileWithEmptyObject.types
+++ b/tests/baselines/reference/requireOfJsonFileWithEmptyObject.types
@@ -1,5 +1,5 @@
 === tests/cases/compiler/file1.ts ===
-import b1 = require('./b');
+import b1 = require('./b.json');
 >b1 : {}
 
 let x = b1;
diff --git a/tests/baselines/reference/requireOfJsonFileWithEmptyObjectWithErrors.errors.txt b/tests/baselines/reference/requireOfJsonFileWithEmptyObjectWithErrors.errors.txt
index 258c4dd60b0..0f10e81f814 100644
--- a/tests/baselines/reference/requireOfJsonFileWithEmptyObjectWithErrors.errors.txt
+++ b/tests/baselines/reference/requireOfJsonFileWithEmptyObjectWithErrors.errors.txt
@@ -4,7 +4,7 @@ tests/cases/compiler/file1.ts(6,13): error TS2339: Property 'b' does not exist o
 
 
 ==== tests/cases/compiler/file1.ts (3 errors) ====
-    import b1 = require('./b');
+    import b1 = require('./b.json');
     let x = b1.a;
                ~
 !!! error TS2339: Property 'a' does not exist on type '{}'.
diff --git a/tests/baselines/reference/requireOfJsonFileWithEmptyObjectWithErrors.js b/tests/baselines/reference/requireOfJsonFileWithEmptyObjectWithErrors.js
index 996f0d4d2db..57122096da0 100644
--- a/tests/baselines/reference/requireOfJsonFileWithEmptyObjectWithErrors.js
+++ b/tests/baselines/reference/requireOfJsonFileWithEmptyObjectWithErrors.js
@@ -1,7 +1,7 @@
 //// [tests/cases/compiler/requireOfJsonFileWithEmptyObjectWithErrors.ts] ////
 
 //// [file1.ts]
-import b1 = require('./b');
+import b1 = require('./b.json');
 let x = b1.a;
 import b2 = require('./b.json');
 if (x) {
@@ -18,7 +18,7 @@ if (x) {
 //// [file1.js]
 "use strict";
 exports.__esModule = true;
-var b1 = require("./b");
+var b1 = require("./b.json");
 var x = b1.a;
 var b2 = require("./b.json");
 if (x) {
diff --git a/tests/baselines/reference/requireOfJsonFileWithEmptyObjectWithErrors.symbols b/tests/baselines/reference/requireOfJsonFileWithEmptyObjectWithErrors.symbols
index b9edfe487ad..819d0c1aabd 100644
--- a/tests/baselines/reference/requireOfJsonFileWithEmptyObjectWithErrors.symbols
+++ b/tests/baselines/reference/requireOfJsonFileWithEmptyObjectWithErrors.symbols
@@ -1,5 +1,5 @@
 === tests/cases/compiler/file1.ts ===
-import b1 = require('./b');
+import b1 = require('./b.json');
 >b1 : Symbol(b1, Decl(file1.ts, 0, 0))
 
 let x = b1.a;
diff --git a/tests/baselines/reference/requireOfJsonFileWithEmptyObjectWithErrors.types b/tests/baselines/reference/requireOfJsonFileWithEmptyObjectWithErrors.types
index 510acba9357..b0eb30cd307 100644
--- a/tests/baselines/reference/requireOfJsonFileWithEmptyObjectWithErrors.types
+++ b/tests/baselines/reference/requireOfJsonFileWithEmptyObjectWithErrors.types
@@ -1,5 +1,5 @@
 === tests/cases/compiler/file1.ts ===
-import b1 = require('./b');
+import b1 = require('./b.json');
 >b1 : {}
 
 let x = b1.a;
diff --git a/tests/baselines/reference/requireOfJsonFileWithNoContent.errors.txt b/tests/baselines/reference/requireOfJsonFileWithNoContent.errors.txt
index c1d050bdaad..e08b474466c 100644
--- a/tests/baselines/reference/requireOfJsonFileWithNoContent.errors.txt
+++ b/tests/baselines/reference/requireOfJsonFileWithNoContent.errors.txt
@@ -4,7 +4,7 @@ tests/cases/compiler/file1.ts(6,13): error TS2339: Property 'b' does not exist o
 
 
 ==== tests/cases/compiler/file1.ts (3 errors) ====
-    import b1 = require('./b');
+    import b1 = require('./b.json');
     let x = b1.a;
                ~
 !!! error TS2339: Property 'a' does not exist on type '{}'.
diff --git a/tests/baselines/reference/requireOfJsonFileWithNoContent.js b/tests/baselines/reference/requireOfJsonFileWithNoContent.js
index 2deed5a2d43..754e616ae49 100644
--- a/tests/baselines/reference/requireOfJsonFileWithNoContent.js
+++ b/tests/baselines/reference/requireOfJsonFileWithNoContent.js
@@ -1,7 +1,7 @@
 //// [tests/cases/compiler/requireOfJsonFileWithNoContent.ts] ////
 
 //// [file1.ts]
-import b1 = require('./b');
+import b1 = require('./b.json');
 let x = b1.a;
 import b2 = require('./b.json');
 if (x) {
@@ -16,7 +16,7 @@ if (x) {
 //// [file1.js]
 "use strict";
 exports.__esModule = true;
-var b1 = require("./b");
+var b1 = require("./b.json");
 var x = b1.a;
 var b2 = require("./b.json");
 if (x) {
diff --git a/tests/baselines/reference/requireOfJsonFileWithNoContent.symbols b/tests/baselines/reference/requireOfJsonFileWithNoContent.symbols
index 6a7a1ebbc51..07d1466a57d 100644
--- a/tests/baselines/reference/requireOfJsonFileWithNoContent.symbols
+++ b/tests/baselines/reference/requireOfJsonFileWithNoContent.symbols
@@ -1,5 +1,5 @@
 === tests/cases/compiler/file1.ts ===
-import b1 = require('./b');
+import b1 = require('./b.json');
 >b1 : Symbol(b1, Decl(file1.ts, 0, 0))
 
 let x = b1.a;
diff --git a/tests/baselines/reference/requireOfJsonFileWithNoContent.types b/tests/baselines/reference/requireOfJsonFileWithNoContent.types
index 5ead1cfc834..e23845e073e 100644
--- a/tests/baselines/reference/requireOfJsonFileWithNoContent.types
+++ b/tests/baselines/reference/requireOfJsonFileWithNoContent.types
@@ -1,5 +1,5 @@
 === tests/cases/compiler/file1.ts ===
-import b1 = require('./b');
+import b1 = require('./b.json');
 >b1 : {}
 
 let x = b1.a;
diff --git a/tests/baselines/reference/requireOfJsonFileWithoutAllowJs.js b/tests/baselines/reference/requireOfJsonFileWithoutAllowJs.js
index ab52cbb1494..eadcd2532f9 100644
--- a/tests/baselines/reference/requireOfJsonFileWithoutAllowJs.js
+++ b/tests/baselines/reference/requireOfJsonFileWithoutAllowJs.js
@@ -1,7 +1,7 @@
 //// [tests/cases/compiler/requireOfJsonFileWithoutAllowJs.ts] ////
 
 //// [file1.ts]
-import b1 = require('./b');
+import b1 = require('./b.json');
 let x = b1.a;
 import b2 = require('./b.json');
 if (x) {
@@ -15,10 +15,15 @@ if (x) {
     "b": "hello"
 }
 
+//// [b.json]
+{
+    "a": true,
+    "b": "hello"
+}
 //// [file1.js]
 "use strict";
 exports.__esModule = true;
-var b1 = require("./b");
+var b1 = require("./b.json");
 var x = b1.a;
 var b2 = require("./b.json");
 if (x) {
diff --git a/tests/baselines/reference/requireOfJsonFileWithoutAllowJs.symbols b/tests/baselines/reference/requireOfJsonFileWithoutAllowJs.symbols
index 1729461ef07..a8f82b6b145 100644
--- a/tests/baselines/reference/requireOfJsonFileWithoutAllowJs.symbols
+++ b/tests/baselines/reference/requireOfJsonFileWithoutAllowJs.symbols
@@ -1,10 +1,12 @@
 === tests/cases/compiler/file1.ts ===
-import b1 = require('./b');
+import b1 = require('./b.json');
 >b1 : Symbol(b1, Decl(file1.ts, 0, 0))
 
 let x = b1.a;
 >x : Symbol(x, Decl(file1.ts, 1, 3))
+>b1.a : Symbol("a", Decl(b.json, 0, 1))
 >b1 : Symbol(b1, Decl(file1.ts, 0, 0))
+>a : Symbol("a", Decl(b.json, 0, 1))
 
 import b2 = require('./b.json');
 >b2 : Symbol(b2, Decl(file1.ts, 1, 13))
@@ -14,11 +16,23 @@ if (x) {
 
     let b = b2.b;
 >b : Symbol(b, Decl(file1.ts, 4, 7))
+>b2.b : Symbol("b", Decl(b.json, 1, 14))
 >b2 : Symbol(b2, Decl(file1.ts, 1, 13))
+>b : Symbol("b", Decl(b.json, 1, 14))
 
     x = (b1.b === b);
 >x : Symbol(x, Decl(file1.ts, 1, 3))
+>b1.b : Symbol("b", Decl(b.json, 1, 14))
 >b1 : Symbol(b1, Decl(file1.ts, 0, 0))
+>b : Symbol("b", Decl(b.json, 1, 14))
 >b : Symbol(b, Decl(file1.ts, 4, 7))
 }
 
+=== tests/cases/compiler/b.json ===
+{
+    "a": true,
+>"a" : Symbol("a", Decl(b.json, 0, 1))
+
+    "b": "hello"
+>"b" : Symbol("b", Decl(b.json, 1, 14))
+}
diff --git a/tests/baselines/reference/requireOfJsonFileWithoutAllowJs.types b/tests/baselines/reference/requireOfJsonFileWithoutAllowJs.types
index 7984743550d..c718c429408 100644
--- a/tests/baselines/reference/requireOfJsonFileWithoutAllowJs.types
+++ b/tests/baselines/reference/requireOfJsonFileWithoutAllowJs.types
@@ -1,33 +1,45 @@
 === tests/cases/compiler/file1.ts ===
-import b1 = require('./b');
->b1 : any
+import b1 = require('./b.json');
+>b1 : { "a": boolean; "b": string; }
 
 let x = b1.a;
->x : any
->b1.a : any
->b1 : any
->a : any
+>x : boolean
+>b1.a : boolean
+>b1 : { "a": boolean; "b": string; }
+>a : boolean
 
 import b2 = require('./b.json');
->b2 : any
+>b2 : { "a": boolean; "b": string; }
 
 if (x) {
->x : any
+>x : boolean
 
     let b = b2.b;
->b : any
->b2.b : any
->b2 : any
->b : any
+>b : string
+>b2.b : string
+>b2 : { "a": boolean; "b": string; }
+>b : string
 
     x = (b1.b === b);
 >x = (b1.b === b) : boolean
->x : any
+>x : boolean
 >(b1.b === b) : boolean
 >b1.b === b : boolean
->b1.b : any
->b1 : any
->b : any
->b : any
+>b1.b : string
+>b1 : { "a": boolean; "b": string; }
+>b : string
+>b : string
 }
 
+=== tests/cases/compiler/b.json ===
+{
+>{    "a": true,    "b": "hello"} : { "a": boolean; "b": string; }
+
+    "a": true,
+>"a" : boolean
+>true : true
+
+    "b": "hello"
+>"b" : string
+>"hello" : "hello"
+}
diff --git a/tests/baselines/reference/requireOfJsonFileWithoutExtension.errors.txt b/tests/baselines/reference/requireOfJsonFileWithoutExtension.errors.txt
new file mode 100644
index 00000000000..799b78c26ee
--- /dev/null
+++ b/tests/baselines/reference/requireOfJsonFileWithoutExtension.errors.txt
@@ -0,0 +1,19 @@
+tests/cases/compiler/file1.ts(1,21): error TS2307: Cannot find module './b'.
+
+
+==== tests/cases/compiler/file1.ts (1 errors) ====
+    import b1 = require('./b'); // This should not resolve
+                        ~~~~~
+!!! error TS2307: Cannot find module './b'.
+    let x = b1.a;
+    import b2 = require('./b.json');
+    if (x) {
+        let b = b2.b;
+        x = (b1.b === b);
+    }
+    
+==== tests/cases/compiler/b.json (0 errors) ====
+    {
+        "a": true,
+        "b": "hello"
+    }
\ No newline at end of file
diff --git a/tests/baselines/reference/requireOfJsonFileWithoutExtension.js b/tests/baselines/reference/requireOfJsonFileWithoutExtension.js
new file mode 100644
index 00000000000..4e9bea900b8
--- /dev/null
+++ b/tests/baselines/reference/requireOfJsonFileWithoutExtension.js
@@ -0,0 +1,32 @@
+//// [tests/cases/compiler/requireOfJsonFileWithoutExtension.ts] ////
+
+//// [file1.ts]
+import b1 = require('./b'); // This should not resolve
+let x = b1.a;
+import b2 = require('./b.json');
+if (x) {
+    let b = b2.b;
+    x = (b1.b === b);
+}
+
+//// [b.json]
+{
+    "a": true,
+    "b": "hello"
+}
+
+//// [b.json]
+{
+    "a": true,
+    "b": "hello"
+}
+//// [file1.js]
+"use strict";
+exports.__esModule = true;
+var b1 = require("./b"); // This should not resolve
+var x = b1.a;
+var b2 = require("./b.json");
+if (x) {
+    var b = b2.b;
+    x = (b1.b === b);
+}
diff --git a/tests/baselines/reference/requireOfJsonFileWithoutExtension.symbols b/tests/baselines/reference/requireOfJsonFileWithoutExtension.symbols
new file mode 100644
index 00000000000..34125a48dd6
--- /dev/null
+++ b/tests/baselines/reference/requireOfJsonFileWithoutExtension.symbols
@@ -0,0 +1,34 @@
+=== tests/cases/compiler/file1.ts ===
+import b1 = require('./b'); // This should not resolve
+>b1 : Symbol(b1, Decl(file1.ts, 0, 0))
+
+let x = b1.a;
+>x : Symbol(x, Decl(file1.ts, 1, 3))
+>b1 : Symbol(b1, Decl(file1.ts, 0, 0))
+
+import b2 = require('./b.json');
+>b2 : Symbol(b2, Decl(file1.ts, 1, 13))
+
+if (x) {
+>x : Symbol(x, Decl(file1.ts, 1, 3))
+
+    let b = b2.b;
+>b : Symbol(b, Decl(file1.ts, 4, 7))
+>b2.b : Symbol("b", Decl(b.json, 1, 14))
+>b2 : Symbol(b2, Decl(file1.ts, 1, 13))
+>b : Symbol("b", Decl(b.json, 1, 14))
+
+    x = (b1.b === b);
+>x : Symbol(x, Decl(file1.ts, 1, 3))
+>b1 : Symbol(b1, Decl(file1.ts, 0, 0))
+>b : Symbol(b, Decl(file1.ts, 4, 7))
+}
+
+=== tests/cases/compiler/b.json ===
+{
+    "a": true,
+>"a" : Symbol("a", Decl(b.json, 0, 1))
+
+    "b": "hello"
+>"b" : Symbol("b", Decl(b.json, 1, 14))
+}
diff --git a/tests/baselines/reference/requireOfJsonFileWithoutExtension.types b/tests/baselines/reference/requireOfJsonFileWithoutExtension.types
new file mode 100644
index 00000000000..5c09cd9063d
--- /dev/null
+++ b/tests/baselines/reference/requireOfJsonFileWithoutExtension.types
@@ -0,0 +1,45 @@
+=== tests/cases/compiler/file1.ts ===
+import b1 = require('./b'); // This should not resolve
+>b1 : any
+
+let x = b1.a;
+>x : any
+>b1.a : any
+>b1 : any
+>a : any
+
+import b2 = require('./b.json');
+>b2 : { "a": boolean; "b": string; }
+
+if (x) {
+>x : any
+
+    let b = b2.b;
+>b : string
+>b2.b : string
+>b2 : { "a": boolean; "b": string; }
+>b : string
+
+    x = (b1.b === b);
+>x = (b1.b === b) : boolean
+>x : any
+>(b1.b === b) : boolean
+>b1.b === b : boolean
+>b1.b : any
+>b1 : any
+>b : any
+>b : string
+}
+
+=== tests/cases/compiler/b.json ===
+{
+>{    "a": true,    "b": "hello"} : { "a": boolean; "b": string; }
+
+    "a": true,
+>"a" : boolean
+>true : true
+
+    "b": "hello"
+>"b" : string
+>"hello" : "hello"
+}
diff --git a/tests/baselines/reference/requireOfJsonFileWithoutExtensionResolvesToTs.js b/tests/baselines/reference/requireOfJsonFileWithoutExtensionResolvesToTs.js
new file mode 100644
index 00000000000..e6908a72a76
--- /dev/null
+++ b/tests/baselines/reference/requireOfJsonFileWithoutExtensionResolvesToTs.js
@@ -0,0 +1,44 @@
+//// [tests/cases/compiler/requireOfJsonFileWithoutExtensionResolvesToTs.ts] ////
+
+//// [file1.ts]
+import c1 = require('./c'); // resolves to c.ts 
+let x2 = c1.a;
+import c2 = require('./c.json'); // resolves to c.json
+if (x2) {
+    let b = c2.b;
+    let x = (c1.b === b);
+}
+
+//// [b.json]
+{
+    "a": true,
+    "b": "hello"
+}
+
+//// [c.json]
+{
+    "a": true,
+    "b": "hello"
+}
+
+//// [c.ts]
+export = { a: true, b: "hello" };
+
+//// [c.js]
+"use strict";
+module.exports = { a: true, b: "hello" };
+//// [c.json]
+{
+    "a": true,
+    "b": "hello"
+}
+//// [file1.js]
+"use strict";
+exports.__esModule = true;
+var c1 = require("./c"); // resolves to c.ts 
+var x2 = c1.a;
+var c2 = require("./c.json"); // resolves to c.json
+if (x2) {
+    var b = c2.b;
+    var x = (c1.b === b);
+}
diff --git a/tests/baselines/reference/requireOfJsonFileWithoutExtensionResolvesToTs.symbols b/tests/baselines/reference/requireOfJsonFileWithoutExtensionResolvesToTs.symbols
new file mode 100644
index 00000000000..fc45f789eac
--- /dev/null
+++ b/tests/baselines/reference/requireOfJsonFileWithoutExtensionResolvesToTs.symbols
@@ -0,0 +1,44 @@
+=== tests/cases/compiler/file1.ts ===
+import c1 = require('./c'); // resolves to c.ts 
+>c1 : Symbol(c1, Decl(file1.ts, 0, 0))
+
+let x2 = c1.a;
+>x2 : Symbol(x2, Decl(file1.ts, 1, 3))
+>c1.a : Symbol(a, Decl(c.ts, 0, 10))
+>c1 : Symbol(c1, Decl(file1.ts, 0, 0))
+>a : Symbol(a, Decl(c.ts, 0, 10))
+
+import c2 = require('./c.json'); // resolves to c.json
+>c2 : Symbol(c2, Decl(file1.ts, 1, 14))
+
+if (x2) {
+>x2 : Symbol(x2, Decl(file1.ts, 1, 3))
+
+    let b = c2.b;
+>b : Symbol(b, Decl(file1.ts, 4, 7))
+>c2.b : Symbol("b", Decl(c.json, 1, 14))
+>c2 : Symbol(c2, Decl(file1.ts, 1, 14))
+>b : Symbol("b", Decl(c.json, 1, 14))
+
+    let x = (c1.b === b);
+>x : Symbol(x, Decl(file1.ts, 5, 7))
+>c1.b : Symbol(b, Decl(c.ts, 0, 19))
+>c1 : Symbol(c1, Decl(file1.ts, 0, 0))
+>b : Symbol(b, Decl(c.ts, 0, 19))
+>b : Symbol(b, Decl(file1.ts, 4, 7))
+}
+
+=== tests/cases/compiler/c.json ===
+{
+    "a": true,
+>"a" : Symbol("a", Decl(c.json, 0, 1))
+
+    "b": "hello"
+>"b" : Symbol("b", Decl(c.json, 1, 14))
+}
+
+=== tests/cases/compiler/c.ts ===
+export = { a: true, b: "hello" };
+>a : Symbol(a, Decl(c.ts, 0, 10))
+>b : Symbol(b, Decl(c.ts, 0, 19))
+
diff --git a/tests/baselines/reference/requireOfJsonFileWithoutExtensionResolvesToTs.types b/tests/baselines/reference/requireOfJsonFileWithoutExtensionResolvesToTs.types
new file mode 100644
index 00000000000..a2faa9c834e
--- /dev/null
+++ b/tests/baselines/reference/requireOfJsonFileWithoutExtensionResolvesToTs.types
@@ -0,0 +1,53 @@
+=== tests/cases/compiler/file1.ts ===
+import c1 = require('./c'); // resolves to c.ts 
+>c1 : { a: boolean; b: string; }
+
+let x2 = c1.a;
+>x2 : boolean
+>c1.a : boolean
+>c1 : { a: boolean; b: string; }
+>a : boolean
+
+import c2 = require('./c.json'); // resolves to c.json
+>c2 : { "a": boolean; "b": string; }
+
+if (x2) {
+>x2 : boolean
+
+    let b = c2.b;
+>b : string
+>c2.b : string
+>c2 : { "a": boolean; "b": string; }
+>b : string
+
+    let x = (c1.b === b);
+>x : boolean
+>(c1.b === b) : boolean
+>c1.b === b : boolean
+>c1.b : string
+>c1 : { a: boolean; b: string; }
+>b : string
+>b : string
+}
+
+=== tests/cases/compiler/c.json ===
+{
+>{    "a": true,    "b": "hello"} : { "a": boolean; "b": string; }
+
+    "a": true,
+>"a" : boolean
+>true : true
+
+    "b": "hello"
+>"b" : string
+>"hello" : "hello"
+}
+
+=== tests/cases/compiler/c.ts ===
+export = { a: true, b: "hello" };
+>{ a: true, b: "hello" } : { a: boolean; b: string; }
+>a : boolean
+>true : true
+>b : string
+>"hello" : "hello"
+
diff --git a/tests/baselines/reference/typeRootsFromMultipleNodeModulesDirectories.trace.json b/tests/baselines/reference/typeRootsFromMultipleNodeModulesDirectories.trace.json
index bee93e5be25..277b27adb32 100644
--- a/tests/baselines/reference/typeRootsFromMultipleNodeModulesDirectories.trace.json
+++ b/tests/baselines/reference/typeRootsFromMultipleNodeModulesDirectories.trace.json
@@ -19,8 +19,6 @@
     "File '/node_modules/xyz.jsx' does not exist.",
     "Loading module 'xyz' from 'node_modules' folder, target file type 'Json'.",
     "Directory '/foo/bar/node_modules' does not exist, skipping all lookups in it.",
-    "File '/foo/node_modules/xyz.json' does not exist.",
-    "File '/node_modules/xyz.json' does not exist.",
     "======== Module name 'xyz' was not resolved. ========",
     "======== Resolving module 'pdq' from '/foo/bar/a.ts'. ========",
     "Module resolution kind is not specified, using 'NodeJs'.",
@@ -42,8 +40,6 @@
     "File '/node_modules/pdq.jsx' does not exist.",
     "Loading module 'pdq' from 'node_modules' folder, target file type 'Json'.",
     "Directory '/foo/bar/node_modules' does not exist, skipping all lookups in it.",
-    "File '/foo/node_modules/pdq.json' does not exist.",
-    "File '/node_modules/pdq.json' does not exist.",
     "======== Module name 'pdq' was not resolved. ========",
     "======== Resolving module 'abc' from '/foo/bar/a.ts'. ========",
     "Module resolution kind is not specified, using 'NodeJs'.",
@@ -65,8 +61,6 @@
     "File '/node_modules/abc.jsx' does not exist.",
     "Loading module 'abc' from 'node_modules' folder, target file type 'Json'.",
     "Directory '/foo/bar/node_modules' does not exist, skipping all lookups in it.",
-    "File '/foo/node_modules/abc.json' does not exist.",
-    "File '/node_modules/abc.json' does not exist.",
     "======== Module name 'abc' was not resolved. ========",
     "======== Resolving type reference directive 'grumpy', containing file '/foo/bar/__inferred type names__.ts', root directory '/foo/node_modules/@types,/node_modules/@types'. ========",
     "Resolving with primary search path '/foo/node_modules/@types, /node_modules/@types'.",
diff --git a/tests/baselines/reference/typeRootsFromNodeModulesInParentDirectory.trace.json b/tests/baselines/reference/typeRootsFromNodeModulesInParentDirectory.trace.json
index 95fdca59f94..4a16a8e7afa 100644
--- a/tests/baselines/reference/typeRootsFromNodeModulesInParentDirectory.trace.json
+++ b/tests/baselines/reference/typeRootsFromNodeModulesInParentDirectory.trace.json
@@ -13,7 +13,6 @@
     "File '/node_modules/xyz.jsx' does not exist.",
     "Loading module 'xyz' from 'node_modules' folder, target file type 'Json'.",
     "Directory '/src/node_modules' does not exist, skipping all lookups in it.",
-    "File '/node_modules/xyz.json' does not exist.",
     "======== Module name 'xyz' was not resolved. ========",
     "======== Resolving type reference directive 'foo', containing file '/src/__inferred type names__.ts', root directory '/node_modules/@types'. ========",
     "Resolving with primary search path '/node_modules/@types'.",
diff --git a/tests/cases/compiler/requireOfJsonFile.ts b/tests/cases/compiler/requireOfJsonFile.ts
index 016c0795620..6c10279aa6f 100644
--- a/tests/cases/compiler/requireOfJsonFile.ts
+++ b/tests/cases/compiler/requireOfJsonFile.ts
@@ -3,7 +3,7 @@
 // @allowJs: true
 
 // @Filename: file1.ts
-import b1 = require('./b');
+import b1 = require('./b.json');
 let x = b1.a;
 import b2 = require('./b.json');
 if (x) {
diff --git a/tests/cases/compiler/requireOfJsonFileNonRelative.ts b/tests/cases/compiler/requireOfJsonFileNonRelative.ts
new file mode 100644
index 00000000000..f769f04282a
--- /dev/null
+++ b/tests/cases/compiler/requireOfJsonFileNonRelative.ts
@@ -0,0 +1,24 @@
+// @module: commonjs
+// @outdir: out/
+// @allowJs: true
+
+// @Filename: /src/projects/file1.ts
+import b1 = require('b.json');
+let x = b1.a;
+import b2 = require('c.json');
+if (x) {
+    let b = b2.b;
+    x = (b1.b === b);
+}
+
+// @Filename: /src/projects/node_modules/b.json
+{
+    "a": true,
+    "b": "hello"
+}
+
+// @Filename: /src/node_modules/c.json
+{
+    "a": true,
+    "b": "hello"
+}
\ No newline at end of file
diff --git a/tests/cases/compiler/requireOfJsonFileNonRelativeWithoutExtension.ts b/tests/cases/compiler/requireOfJsonFileNonRelativeWithoutExtension.ts
new file mode 100644
index 00000000000..4e4b4dda6eb
--- /dev/null
+++ b/tests/cases/compiler/requireOfJsonFileNonRelativeWithoutExtension.ts
@@ -0,0 +1,25 @@
+// @module: commonjs
+// @outdir: out/
+// @allowJs: true
+
+// @Filename: /src/projects/file1.ts
+import d = require("d.json"); // Should fail
+import e = require("e"); // Should fail
+
+// @Filename: /src/projects/node_modules/b.json
+{
+    "a": true,
+    "b": "hello"
+}
+
+// @Filename: /src/projects/node_modules/e.json
+{
+    "a": true,
+    "b": "hello"
+}
+
+// @Filename: /src/node_modules/c.json
+{
+    "a": true,
+    "b": "hello"
+}
\ No newline at end of file
diff --git a/tests/cases/compiler/requireOfJsonFileNonRelativeWithoutExtensionResolvesToTs.ts b/tests/cases/compiler/requireOfJsonFileNonRelativeWithoutExtensionResolvesToTs.ts
new file mode 100644
index 00000000000..27126a14545
--- /dev/null
+++ b/tests/cases/compiler/requireOfJsonFileNonRelativeWithoutExtensionResolvesToTs.ts
@@ -0,0 +1,16 @@
+// @module: commonjs
+// @outdir: out/
+// @allowJs: true
+
+// @Filename: /src/projects/file1.ts
+import f = require("f"); // should work to f.ts
+let fnumber: number = f;
+
+// @Filename: /src/node_modules/f.json
+{
+    "a": true,
+    "b": "hello"
+}
+
+// @Filename: /src/node_modules/f.ts
+export = 10;
\ No newline at end of file
diff --git a/tests/cases/compiler/requireOfJsonFileWithEmptyObject.ts b/tests/cases/compiler/requireOfJsonFileWithEmptyObject.ts
index 05f1d2d637c..030ddf16a8b 100644
--- a/tests/cases/compiler/requireOfJsonFileWithEmptyObject.ts
+++ b/tests/cases/compiler/requireOfJsonFileWithEmptyObject.ts
@@ -3,7 +3,7 @@
 // @allowJs: true
 
 // @Filename: file1.ts
-import b1 = require('./b');
+import b1 = require('./b.json');
 let x = b1;
 import b2 = require('./b.json');
 if (x) {
diff --git a/tests/cases/compiler/requireOfJsonFileWithEmptyObjectWithErrors.ts b/tests/cases/compiler/requireOfJsonFileWithEmptyObjectWithErrors.ts
index 31ab0ea0a7c..6d8edd2c0cb 100644
--- a/tests/cases/compiler/requireOfJsonFileWithEmptyObjectWithErrors.ts
+++ b/tests/cases/compiler/requireOfJsonFileWithEmptyObjectWithErrors.ts
@@ -3,7 +3,7 @@
 // @allowJs: true
 
 // @Filename: file1.ts
-import b1 = require('./b');
+import b1 = require('./b.json');
 let x = b1.a;
 import b2 = require('./b.json');
 if (x) {
diff --git a/tests/cases/compiler/requireOfJsonFileWithNoContent.ts b/tests/cases/compiler/requireOfJsonFileWithNoContent.ts
index 4d3c63c6ffa..0f9bbbb28fb 100644
--- a/tests/cases/compiler/requireOfJsonFileWithNoContent.ts
+++ b/tests/cases/compiler/requireOfJsonFileWithNoContent.ts
@@ -3,7 +3,7 @@
 // @allowJs: true
 
 // @Filename: file1.ts
-import b1 = require('./b');
+import b1 = require('./b.json');
 let x = b1.a;
 import b2 = require('./b.json');
 if (x) {
diff --git a/tests/cases/compiler/requireOfJsonFileWithoutAllowJs.ts b/tests/cases/compiler/requireOfJsonFileWithoutAllowJs.ts
index d214bcda450..9043be7d44c 100644
--- a/tests/cases/compiler/requireOfJsonFileWithoutAllowJs.ts
+++ b/tests/cases/compiler/requireOfJsonFileWithoutAllowJs.ts
@@ -2,7 +2,7 @@
 // @outdir: out/
 
 // @Filename: file1.ts
-import b1 = require('./b');
+import b1 = require('./b.json');
 let x = b1.a;
 import b2 = require('./b.json');
 if (x) {
diff --git a/tests/cases/compiler/requireOfJsonFileWithoutExtension.ts b/tests/cases/compiler/requireOfJsonFileWithoutExtension.ts
new file mode 100644
index 00000000000..7739b1eb7ce
--- /dev/null
+++ b/tests/cases/compiler/requireOfJsonFileWithoutExtension.ts
@@ -0,0 +1,18 @@
+// @module: commonjs
+// @outdir: out/
+// @allowJs: true
+
+// @Filename: file1.ts
+import b1 = require('./b'); // This should not resolve
+let x = b1.a;
+import b2 = require('./b.json');
+if (x) {
+    let b = b2.b;
+    x = (b1.b === b);
+}
+
+// @Filename: b.json
+{
+    "a": true,
+    "b": "hello"
+}
\ No newline at end of file
diff --git a/tests/cases/compiler/requireOfJsonFileWithoutExtensionResolvesToTs.ts b/tests/cases/compiler/requireOfJsonFileWithoutExtensionResolvesToTs.ts
new file mode 100644
index 00000000000..a3974eaf282
--- /dev/null
+++ b/tests/cases/compiler/requireOfJsonFileWithoutExtensionResolvesToTs.ts
@@ -0,0 +1,27 @@
+// @module: commonjs
+// @outdir: out/
+// @allowJs: true
+
+// @Filename: file1.ts
+import c1 = require('./c'); // resolves to c.ts 
+let x2 = c1.a;
+import c2 = require('./c.json'); // resolves to c.json
+if (x2) {
+    let b = c2.b;
+    let x = (c1.b === b);
+}
+
+// @Filename: b.json
+{
+    "a": true,
+    "b": "hello"
+}
+
+// @Filename: c.json
+{
+    "a": true,
+    "b": "hello"
+}
+
+// @Filename: c.ts
+export = { a: true, b: "hello" };
\ No newline at end of file