diff --git a/src/compiler/program.ts b/src/compiler/program.ts
index a9c64f3ecbe3a..b7830653c861d 100644
--- a/src/compiler/program.ts
+++ b/src/compiler/program.ts
@@ -725,6 +725,14 @@ namespace ts {
         }
 
         function getSyntacticDiagnosticsForFile(sourceFile: SourceFile): Diagnostic[] {
+            // For JavaScript files, we report semantic errors for using TypeScript-only
+            // constructs from within a JavaScript file as syntactic errors.
+            if (isSourceFileJavaScript(sourceFile)) {
+                if (!sourceFile.additionalSyntacticDiagnostics) {
+                    sourceFile.additionalSyntacticDiagnostics = getJavaScriptSyntacticDiagnosticsForFile(sourceFile);
+                }
+                return concatenate(sourceFile.additionalSyntacticDiagnostics, sourceFile.parseDiagnostics);
+            }
             return sourceFile.parseDiagnostics;
         }
 
@@ -757,12 +765,10 @@ namespace ts {
 
                 Debug.assert(!!sourceFile.bindDiagnostics);
                 const bindDiagnostics = sourceFile.bindDiagnostics;
-                // For JavaScript files, we don't want to report the normal typescript semantic errors.
-                // Instead, we just report errors for using TypeScript-only constructs from within a
-                // JavaScript file.
-                const checkDiagnostics = isSourceFileJavaScript(sourceFile) ?
-                    getJavaScriptSemanticDiagnosticsForFile(sourceFile) :
-                    typeChecker.getDiagnostics(sourceFile, cancellationToken);
+                // 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 checkDiagnostics = isSourceFileJavaScript(sourceFile) ? [] : typeChecker.getDiagnostics(sourceFile, cancellationToken);
                 const fileProcessingDiagnosticsInFile = fileProcessingDiagnostics.getDiagnostics(sourceFile.fileName);
                 const programDiagnosticsInFile = programDiagnostics.getDiagnostics(sourceFile.fileName);
 
@@ -770,7 +776,7 @@ namespace ts {
             });
         }
 
-        function getJavaScriptSemanticDiagnosticsForFile(sourceFile: SourceFile): Diagnostic[] {
+        function getJavaScriptSyntacticDiagnosticsForFile(sourceFile: SourceFile): Diagnostic[] {
             return runWithCancellationToken(() => {
                 const diagnostics: Diagnostic[] = [];
                 walk(sourceFile);
diff --git a/src/compiler/types.ts b/src/compiler/types.ts
index f9ec3e9f268cc..ff0ba2fde867b 100644
--- a/src/compiler/types.ts
+++ b/src/compiler/types.ts
@@ -2024,6 +2024,9 @@ namespace ts {
         // as well as code diagnostics).
         /* @internal */ parseDiagnostics: Diagnostic[];
 
+        // Stores additional file level diagnostics reported by the program
+        /* @internal */ additionalSyntacticDiagnostics?: Diagnostic[];
+
         // File level diagnostics reported by the binder.
         /* @internal */ bindDiagnostics: Diagnostic[];
 
diff --git a/tests/cases/fourslash/getJavaScriptSemanticDiagnostics1.ts b/tests/cases/fourslash/getJavaScriptSyntacticDiagnostics1.ts
similarity index 83%
rename from tests/cases/fourslash/getJavaScriptSemanticDiagnostics1.ts
rename to tests/cases/fourslash/getJavaScriptSyntacticDiagnostics1.ts
index a94318c84fde9..8c151742b752b 100644
--- a/tests/cases/fourslash/getJavaScriptSemanticDiagnostics1.ts
+++ b/tests/cases/fourslash/getJavaScriptSyntacticDiagnostics1.ts
@@ -4,7 +4,7 @@
 // @Filename: a.js
 //// import a = b;
 
-verify.getSemanticDiagnostics(`[
+verify.getSyntacticDiagnostics(`[
   {
     "message": "'import ... =' can only be used in a .ts file.",
     "start": 0,
diff --git a/tests/cases/fourslash/getJavaScriptSemanticDiagnostics10.ts b/tests/cases/fourslash/getJavaScriptSyntacticDiagnostics10.ts
similarity index 84%
rename from tests/cases/fourslash/getJavaScriptSemanticDiagnostics10.ts
rename to tests/cases/fourslash/getJavaScriptSyntacticDiagnostics10.ts
index 957357fc2c110..206c1a6e2cfc0 100644
--- a/tests/cases/fourslash/getJavaScriptSemanticDiagnostics10.ts
+++ b/tests/cases/fourslash/getJavaScriptSyntacticDiagnostics10.ts
@@ -4,7 +4,7 @@
 // @Filename: a.js
 //// function F<T>() { }
 
-verify.getSemanticDiagnostics(`[
+verify.getSyntacticDiagnostics(`[
   {
     "message": "'type parameter declarations' can only be used in a .ts file.",
     "start": 11,
diff --git a/tests/cases/fourslash/getJavaScriptSemanticDiagnostics11.ts b/tests/cases/fourslash/getJavaScriptSyntacticDiagnostics11.ts
similarity index 84%
rename from tests/cases/fourslash/getJavaScriptSemanticDiagnostics11.ts
rename to tests/cases/fourslash/getJavaScriptSyntacticDiagnostics11.ts
index d9c16fca65164..d9b1d35b5c65b 100644
--- a/tests/cases/fourslash/getJavaScriptSemanticDiagnostics11.ts
+++ b/tests/cases/fourslash/getJavaScriptSyntacticDiagnostics11.ts
@@ -4,7 +4,7 @@
 // @Filename: a.js
 //// function F(): number { }
 
-verify.getSemanticDiagnostics(`[
+verify.getSyntacticDiagnostics(`[
   {
     "message": "'types' can only be used in a .ts file.",
     "start": 14,
diff --git a/tests/cases/fourslash/getJavaScriptSemanticDiagnostics12.ts b/tests/cases/fourslash/getJavaScriptSyntacticDiagnostics12.ts
similarity index 83%
rename from tests/cases/fourslash/getJavaScriptSemanticDiagnostics12.ts
rename to tests/cases/fourslash/getJavaScriptSyntacticDiagnostics12.ts
index b4dcf07674323..cf244f7cfa25f 100644
--- a/tests/cases/fourslash/getJavaScriptSemanticDiagnostics12.ts
+++ b/tests/cases/fourslash/getJavaScriptSyntacticDiagnostics12.ts
@@ -4,7 +4,7 @@
 // @Filename: a.js
 //// declare var v;
 
-verify.getSemanticDiagnostics(`[
+verify.getSyntacticDiagnostics(`[
   {
     "message": "'declare' can only be used in a .ts file.",
     "start": 0,
diff --git a/tests/cases/fourslash/getJavaScriptSemanticDiagnostics13.ts b/tests/cases/fourslash/getJavaScriptSyntacticDiagnostics13.ts
similarity index 83%
rename from tests/cases/fourslash/getJavaScriptSemanticDiagnostics13.ts
rename to tests/cases/fourslash/getJavaScriptSyntacticDiagnostics13.ts
index a20bccc088763..aaf3289fcfe4c 100644
--- a/tests/cases/fourslash/getJavaScriptSemanticDiagnostics13.ts
+++ b/tests/cases/fourslash/getJavaScriptSyntacticDiagnostics13.ts
@@ -4,7 +4,7 @@
 // @Filename: a.js
 //// var v: () => number;
 
-verify.getSemanticDiagnostics(`[
+verify.getSyntacticDiagnostics(`[
   {
     "message": "'types' can only be used in a .ts file.",
     "start": 7,
diff --git a/tests/cases/fourslash/getJavaScriptSemanticDiagnostics14.ts b/tests/cases/fourslash/getJavaScriptSyntacticDiagnostics14.ts
similarity index 83%
rename from tests/cases/fourslash/getJavaScriptSemanticDiagnostics14.ts
rename to tests/cases/fourslash/getJavaScriptSyntacticDiagnostics14.ts
index 4f7673be38455..a41d88dd6757f 100644
--- a/tests/cases/fourslash/getJavaScriptSemanticDiagnostics14.ts
+++ b/tests/cases/fourslash/getJavaScriptSyntacticDiagnostics14.ts
@@ -4,7 +4,7 @@
 // @Filename: a.js
 //// Foo<number>();
 
-verify.getSemanticDiagnostics(`[
+verify.getSyntacticDiagnostics(`[
   {
     "message": "'type arguments' can only be used in a .ts file.",
     "start": 4,
diff --git a/tests/cases/fourslash/getJavaScriptSemanticDiagnostics15.ts b/tests/cases/fourslash/getJavaScriptSyntacticDiagnostics15.ts
similarity index 84%
rename from tests/cases/fourslash/getJavaScriptSemanticDiagnostics15.ts
rename to tests/cases/fourslash/getJavaScriptSyntacticDiagnostics15.ts
index f7cd4db362621..93430a9a004d6 100644
--- a/tests/cases/fourslash/getJavaScriptSemanticDiagnostics15.ts
+++ b/tests/cases/fourslash/getJavaScriptSyntacticDiagnostics15.ts
@@ -4,7 +4,7 @@
 // @Filename: a.js
 //// function F(public p) { }
 
-verify.getSemanticDiagnostics(`[
+verify.getSyntacticDiagnostics(`[
   {
     "message": "'parameter modifiers' can only be used in a .ts file.",
     "start": 11,
diff --git a/tests/cases/fourslash/getJavaScriptSemanticDiagnostics16.ts b/tests/cases/fourslash/getJavaScriptSyntacticDiagnostics16.ts
similarity index 83%
rename from tests/cases/fourslash/getJavaScriptSemanticDiagnostics16.ts
rename to tests/cases/fourslash/getJavaScriptSyntacticDiagnostics16.ts
index cd19bd580cc25..60e0684b10628 100644
--- a/tests/cases/fourslash/getJavaScriptSemanticDiagnostics16.ts
+++ b/tests/cases/fourslash/getJavaScriptSyntacticDiagnostics16.ts
@@ -4,7 +4,7 @@
 // @Filename: a.js
 //// function F(p?) { }
 
-verify.getSemanticDiagnostics(`[
+verify.getSyntacticDiagnostics(`[
   {
     "message": "'?' can only be used in a .ts file.",
     "start": 12,
diff --git a/tests/cases/fourslash/getJavaScriptSemanticDiagnostics17.ts b/tests/cases/fourslash/getJavaScriptSyntacticDiagnostics17.ts
similarity index 84%
rename from tests/cases/fourslash/getJavaScriptSemanticDiagnostics17.ts
rename to tests/cases/fourslash/getJavaScriptSyntacticDiagnostics17.ts
index 5a1ec6d92cf24..3a57917b2ac56 100644
--- a/tests/cases/fourslash/getJavaScriptSemanticDiagnostics17.ts
+++ b/tests/cases/fourslash/getJavaScriptSyntacticDiagnostics17.ts
@@ -4,7 +4,7 @@
 // @Filename: a.js
 //// function F(a: number) { }
 
-verify.getSemanticDiagnostics(`[
+verify.getSyntacticDiagnostics(`[
   {
     "message": "'types' can only be used in a .ts file.",
     "start": 14,
diff --git a/tests/cases/fourslash/getJavaScriptSemanticDiagnostics18.ts b/tests/cases/fourslash/getJavaScriptSyntacticDiagnostics18.ts
similarity index 86%
rename from tests/cases/fourslash/getJavaScriptSemanticDiagnostics18.ts
rename to tests/cases/fourslash/getJavaScriptSyntacticDiagnostics18.ts
index 707d1537fc5c7..d253cb636114d 100644
--- a/tests/cases/fourslash/getJavaScriptSemanticDiagnostics18.ts
+++ b/tests/cases/fourslash/getJavaScriptSyntacticDiagnostics18.ts
@@ -9,7 +9,7 @@
 ////}
 
 goTo.file("a.js");
-verify.getSemanticDiagnostics(`[
+verify.getSyntacticDiagnostics(`[
   {
     "message": "\'public\' can only be used in a .ts file.",
     "start": 93,
@@ -25,7 +25,7 @@ verify.getSemanticDiagnostics(`[
 ////}
 
 goTo.file("b.js");
-verify.getSemanticDiagnostics(`[
+verify.getSyntacticDiagnostics(`[
   {
     "message": "'types' can only be used in a .ts file.",
     "start": 17,
diff --git a/tests/cases/fourslash/getJavaScriptSemanticDiagnostics19.ts b/tests/cases/fourslash/getJavaScriptSyntacticDiagnostics19.ts
similarity index 83%
rename from tests/cases/fourslash/getJavaScriptSemanticDiagnostics19.ts
rename to tests/cases/fourslash/getJavaScriptSyntacticDiagnostics19.ts
index a7fbe3e0ecc64..7729a6ea47020 100644
--- a/tests/cases/fourslash/getJavaScriptSemanticDiagnostics19.ts
+++ b/tests/cases/fourslash/getJavaScriptSyntacticDiagnostics19.ts
@@ -4,7 +4,7 @@
 // @Filename: a.js
 //// enum E { }
 
-verify.getSemanticDiagnostics(`[
+verify.getSyntacticDiagnostics(`[
   {
     "message": "'enum declarations' can only be used in a .ts file.",
     "start": 5,
diff --git a/tests/cases/fourslash/getJavaScriptSemanticDiagnostics2.ts b/tests/cases/fourslash/getJavaScriptSyntacticDiagnostics2.ts
similarity index 83%
rename from tests/cases/fourslash/getJavaScriptSemanticDiagnostics2.ts
rename to tests/cases/fourslash/getJavaScriptSyntacticDiagnostics2.ts
index 9ab29b417984b..74e6a9ab089b6 100644
--- a/tests/cases/fourslash/getJavaScriptSemanticDiagnostics2.ts
+++ b/tests/cases/fourslash/getJavaScriptSyntacticDiagnostics2.ts
@@ -4,7 +4,7 @@
 // @Filename: a.js
 //// export = b;
 
-verify.getSemanticDiagnostics(`[
+verify.getSyntacticDiagnostics(`[
   {
     "message": "'export=' can only be used in a .ts file.",
     "start": 0,
diff --git a/tests/cases/fourslash/getJavaScriptSemanticDiagnostics21.ts b/tests/cases/fourslash/getJavaScriptSyntacticDiagnostics21.ts
similarity index 100%
rename from tests/cases/fourslash/getJavaScriptSemanticDiagnostics21.ts
rename to tests/cases/fourslash/getJavaScriptSyntacticDiagnostics21.ts
diff --git a/tests/cases/fourslash/getJavaScriptSemanticDiagnostics22.ts b/tests/cases/fourslash/getJavaScriptSyntacticDiagnostics22.ts
similarity index 100%
rename from tests/cases/fourslash/getJavaScriptSemanticDiagnostics22.ts
rename to tests/cases/fourslash/getJavaScriptSyntacticDiagnostics22.ts
diff --git a/tests/cases/fourslash/getJavaScriptSemanticDiagnostics23.ts b/tests/cases/fourslash/getJavaScriptSyntacticDiagnostics23.ts
similarity index 100%
rename from tests/cases/fourslash/getJavaScriptSemanticDiagnostics23.ts
rename to tests/cases/fourslash/getJavaScriptSyntacticDiagnostics23.ts
diff --git a/tests/cases/fourslash/getJavaScriptSemanticDiagnostics24.ts b/tests/cases/fourslash/getJavaScriptSyntacticDiagnostics24.ts
similarity index 100%
rename from tests/cases/fourslash/getJavaScriptSemanticDiagnostics24.ts
rename to tests/cases/fourslash/getJavaScriptSyntacticDiagnostics24.ts
diff --git a/tests/cases/fourslash/getJavaScriptSemanticDiagnostics3.ts b/tests/cases/fourslash/getJavaScriptSyntacticDiagnostics3.ts
similarity index 84%
rename from tests/cases/fourslash/getJavaScriptSemanticDiagnostics3.ts
rename to tests/cases/fourslash/getJavaScriptSyntacticDiagnostics3.ts
index 3aff51d881b09..3528f33332975 100644
--- a/tests/cases/fourslash/getJavaScriptSemanticDiagnostics3.ts
+++ b/tests/cases/fourslash/getJavaScriptSyntacticDiagnostics3.ts
@@ -4,7 +4,7 @@
 // @Filename: a.js
 //// class C<T> { }
 
-verify.getSemanticDiagnostics(`[
+verify.getSyntacticDiagnostics(`[
   {
     "message": "'type parameter declarations' can only be used in a .ts file.",
     "start": 8,
diff --git a/tests/cases/fourslash/getJavaScriptSemanticDiagnostics4.ts b/tests/cases/fourslash/getJavaScriptSyntacticDiagnostics4.ts
similarity index 83%
rename from tests/cases/fourslash/getJavaScriptSemanticDiagnostics4.ts
rename to tests/cases/fourslash/getJavaScriptSyntacticDiagnostics4.ts
index 99319b047e63c..3b849b08ae070 100644
--- a/tests/cases/fourslash/getJavaScriptSemanticDiagnostics4.ts
+++ b/tests/cases/fourslash/getJavaScriptSyntacticDiagnostics4.ts
@@ -4,7 +4,7 @@
 // @Filename: a.js
 //// public class C { }
 
-verify.getSemanticDiagnostics(`[
+verify.getSyntacticDiagnostics(`[
   {
     "message": "'public' can only be used in a .ts file.",
     "start": 0,
diff --git a/tests/cases/fourslash/getJavaScriptSemanticDiagnostics5.ts b/tests/cases/fourslash/getJavaScriptSyntacticDiagnostics5.ts
similarity index 84%
rename from tests/cases/fourslash/getJavaScriptSemanticDiagnostics5.ts
rename to tests/cases/fourslash/getJavaScriptSyntacticDiagnostics5.ts
index 18df3500bd975..985e3284025d8 100644
--- a/tests/cases/fourslash/getJavaScriptSemanticDiagnostics5.ts
+++ b/tests/cases/fourslash/getJavaScriptSyntacticDiagnostics5.ts
@@ -4,7 +4,7 @@
 // @Filename: a.js
 //// class C implements D { }
 
-verify.getSemanticDiagnostics(`[
+verify.getSyntacticDiagnostics(`[
   {
     "message": "'implements clauses' can only be used in a .ts file.",
     "start": 8,
diff --git a/tests/cases/fourslash/getJavaScriptSemanticDiagnostics6.ts b/tests/cases/fourslash/getJavaScriptSyntacticDiagnostics6.ts
similarity index 84%
rename from tests/cases/fourslash/getJavaScriptSemanticDiagnostics6.ts
rename to tests/cases/fourslash/getJavaScriptSyntacticDiagnostics6.ts
index e18f8f9be52c4..a0042a0529b7d 100644
--- a/tests/cases/fourslash/getJavaScriptSemanticDiagnostics6.ts
+++ b/tests/cases/fourslash/getJavaScriptSyntacticDiagnostics6.ts
@@ -4,7 +4,7 @@
 // @Filename: a.js
 //// interface I { }
 
-verify.getSemanticDiagnostics(`[
+verify.getSyntacticDiagnostics(`[
   {
     "message": "'interface declarations' can only be used in a .ts file.",
     "start": 10,
diff --git a/tests/cases/fourslash/getJavaScriptSemanticDiagnostics7.ts b/tests/cases/fourslash/getJavaScriptSyntacticDiagnostics7.ts
similarity index 84%
rename from tests/cases/fourslash/getJavaScriptSemanticDiagnostics7.ts
rename to tests/cases/fourslash/getJavaScriptSyntacticDiagnostics7.ts
index 32cad0e5a07bf..64216d1e36488 100644
--- a/tests/cases/fourslash/getJavaScriptSemanticDiagnostics7.ts
+++ b/tests/cases/fourslash/getJavaScriptSyntacticDiagnostics7.ts
@@ -4,7 +4,7 @@
 // @Filename: a.js
 //// module M { }
 
-verify.getSemanticDiagnostics(`[
+verify.getSyntacticDiagnostics(`[
   {
     "message": "'module declarations' can only be used in a .ts file.",
     "start": 7,
diff --git a/tests/cases/fourslash/getJavaScriptSemanticDiagnostics8.ts b/tests/cases/fourslash/getJavaScriptSyntacticDiagnostics8.ts
similarity index 83%
rename from tests/cases/fourslash/getJavaScriptSemanticDiagnostics8.ts
rename to tests/cases/fourslash/getJavaScriptSyntacticDiagnostics8.ts
index 562f42124aeae..296f4f7445e76 100644
--- a/tests/cases/fourslash/getJavaScriptSemanticDiagnostics8.ts
+++ b/tests/cases/fourslash/getJavaScriptSyntacticDiagnostics8.ts
@@ -4,7 +4,7 @@
 // @Filename: a.js
 //// type a = b;
 
-verify.getSemanticDiagnostics(`[
+verify.getSyntacticDiagnostics(`[
   {
     "message": "'type aliases' can only be used in a .ts file.",
     "start": 5,
diff --git a/tests/cases/fourslash/getJavaScriptSemanticDiagnostics9.ts b/tests/cases/fourslash/getJavaScriptSyntacticDiagnostics9.ts
similarity index 84%
rename from tests/cases/fourslash/getJavaScriptSemanticDiagnostics9.ts
rename to tests/cases/fourslash/getJavaScriptSyntacticDiagnostics9.ts
index 4c531b5255b92..f2c20a52ee971 100644
--- a/tests/cases/fourslash/getJavaScriptSemanticDiagnostics9.ts
+++ b/tests/cases/fourslash/getJavaScriptSyntacticDiagnostics9.ts
@@ -4,7 +4,7 @@
 // @Filename: a.js
 //// public function F() { }
 
-verify.getSemanticDiagnostics(`[
+verify.getSyntacticDiagnostics(`[
   {
     "message": "'public' can only be used in a .ts file.",
     "start": 0,
diff --git a/tests/cases/fourslash/server/getJavaScriptSyntacticDiagnostics02.ts b/tests/cases/fourslash/server/getJavaScriptSyntacticDiagnostics02.ts
new file mode 100644
index 0000000000000..dd9becad10b70
--- /dev/null
+++ b/tests/cases/fourslash/server/getJavaScriptSyntacticDiagnostics02.ts
@@ -0,0 +1,40 @@
+/// <reference path="../fourslash.ts" />
+
+// @allowJs: true
+// @Filename: b.js
+//// var a = "a";
+//// var b: boolean = true;
+//// function foo(): string { }
+//// var var = "c";
+
+verify.getSyntacticDiagnostics(`[
+  {
+    "message": "\'types\' can only be used in a .ts file.",
+    "start": 20,
+    "length": 7,
+    "category": "error",
+    "code": 8010
+  },
+  {
+    "message": "Variable declaration expected.",
+    "start": 67,
+    "length": 3,
+    "category": "error",
+    "code": 1134
+  },
+  {
+    "message": "Variable declaration expected.",
+    "start": 71,
+    "length": 1,
+    "category": "error",
+    "code": 1134
+  },
+  {
+    "message": "Variable declaration expected.",
+    "start": 73,
+    "length": 3,
+    "category": "error",
+    "code": 1134
+  }
+]`);
+verify.getSemanticDiagnostics(`[]`);
\ No newline at end of file