diff --git a/src/compiler/commandLineParser.ts b/src/compiler/commandLineParser.ts
index 7b508351aec..0bea9468432 100644
--- a/src/compiler/commandLineParser.ts
+++ b/src/compiler/commandLineParser.ts
@@ -1053,7 +1053,7 @@ namespace ts {
                     errors.push(createDiagnosticForNodeInSourceFile(sourceFile, element.name, extraKeyDiagnosticMessage, keyText));
                 }
                 const value = convertPropertyValueToJson(element.initializer, option);
-                if (typeof keyText !== undefined && typeof value !== undefined) {
+                if (typeof keyText !== "undefined" && typeof value !== "undefined") {
                     result[keyText] = value;
                     // Notify key value set, if user asked for it
                     if (jsonConversionNotifier &&
diff --git a/src/compiler/core.ts b/src/compiler/core.ts
index 8e5bf017924..7c9811c41c8 100644
--- a/src/compiler/core.ts
+++ b/src/compiler/core.ts
@@ -955,7 +955,7 @@ namespace ts {
      * @param map A map-like.
      * @param key A property key.
      */
-    export function hasProperty<T>(map: MapLike<T>, key: string): boolean {
+    export function hasProperty(map: MapLike<any>, key: string): boolean {
         return hasOwnProperty.call(map, key);
     }
 
@@ -2344,7 +2344,7 @@ namespace ts {
 
         export function fail(message?: string, stackCrawlMark?: Function): void {
             debugger;
-            const e = new Error(message ? `Debug Failure. ` : "Debug Failure.");
+            const e = new Error(message ? `Debug Failure. ${message}` : "Debug Failure.");
             if ((<any>Error).captureStackTrace) {
                 (<any>Error).captureStackTrace(e, stackCrawlMark || fail);
             }
diff --git a/src/compiler/parser.ts b/src/compiler/parser.ts
index 0f08d677910..a8234b850e2 100644
--- a/src/compiler/parser.ts
+++ b/src/compiler/parser.ts
@@ -3733,7 +3733,7 @@ namespace ts {
             // 3)we have a MemberExpression which either completes the LeftHandSideExpression,
             // or starts the beginning of the first four CallExpression productions.
             let expression: MemberExpression;
-            if (token() === SyntaxKind.ImportKeyword) {
+            if (token() === SyntaxKind.ImportKeyword && lookAhead(nextTokenIsOpenParenOrLessThan)) {
                 // We don't want to eagerly consume all import keyword as import call expression so we look a head to find "("
                 // For example:
                 //      var foo3 = require("subfolder
diff --git a/src/compiler/program.ts b/src/compiler/program.ts
index bbc0fa09780..2f6b0539872 100644
--- a/src/compiler/program.ts
+++ b/src/compiler/program.ts
@@ -803,6 +803,10 @@ namespace ts {
                         // moduleAugmentations has changed
                         oldProgram.structureIsReused = StructureIsReused.SafeModules;
                     }
+                    if ((oldSourceFile.flags & NodeFlags.PossiblyContainsDynamicImport) !== (newSourceFile.flags & NodeFlags.PossiblyContainsDynamicImport)) {
+                        // dynamicImport has changed
+                        oldProgram.structureIsReused = StructureIsReused.SafeModules;
+                    }
 
                     if (!arrayIsEqualTo(oldSourceFile.typeReferenceDirectives, newSourceFile.typeReferenceDirectives, fileReferenceIsEqualTo)) {
                         // 'types' references has changed
diff --git a/tests/baselines/reference/importCallExpressionIncorrect1.errors.txt b/tests/baselines/reference/importCallExpressionIncorrect1.errors.txt
new file mode 100644
index 00000000000..4b22567454e
--- /dev/null
+++ b/tests/baselines/reference/importCallExpressionIncorrect1.errors.txt
@@ -0,0 +1,11 @@
+tests/cases/conformance/dynamicImport/1.ts(2,1): error TS1109: Expression expected.
+
+
+==== tests/cases/conformance/dynamicImport/0.ts (0 errors) ====
+    export function foo() { return "foo"; }
+    
+==== tests/cases/conformance/dynamicImport/1.ts (1 errors) ====
+    import
+    import { foo } from './0';
+    ~~~~~~
+!!! error TS1109: Expression expected.
\ No newline at end of file
diff --git a/tests/baselines/reference/importCallExpressionIncorrect1.js b/tests/baselines/reference/importCallExpressionIncorrect1.js
new file mode 100644
index 00000000000..c007d1c8c6f
--- /dev/null
+++ b/tests/baselines/reference/importCallExpressionIncorrect1.js
@@ -0,0 +1,13 @@
+//// [tests/cases/conformance/dynamicImport/importCallExpressionIncorrect1.ts] ////
+
+//// [0.ts]
+export function foo() { return "foo"; }
+
+//// [1.ts]
+import
+import { foo } from './0';
+
+//// [0.js]
+export function foo() { return "foo"; }
+//// [1.js]
+import ;
diff --git a/tests/baselines/reference/importCallExpressionIncorrect2.errors.txt b/tests/baselines/reference/importCallExpressionIncorrect2.errors.txt
new file mode 100644
index 00000000000..a83f6f9a1f9
--- /dev/null
+++ b/tests/baselines/reference/importCallExpressionIncorrect2.errors.txt
@@ -0,0 +1,10 @@
+tests/cases/conformance/dynamicImport/1.ts(1,9): error TS1109: Expression expected.
+
+
+==== tests/cases/conformance/dynamicImport/0.ts (0 errors) ====
+    export function foo() { return "foo"; }
+    
+==== tests/cases/conformance/dynamicImport/1.ts (1 errors) ====
+    var x = import { foo } from './0';
+            ~~~~~~
+!!! error TS1109: Expression expected.
\ No newline at end of file
diff --git a/tests/baselines/reference/importCallExpressionIncorrect2.js b/tests/baselines/reference/importCallExpressionIncorrect2.js
new file mode 100644
index 00000000000..718bef9b9a8
--- /dev/null
+++ b/tests/baselines/reference/importCallExpressionIncorrect2.js
@@ -0,0 +1,12 @@
+//// [tests/cases/conformance/dynamicImport/importCallExpressionIncorrect2.ts] ////
+
+//// [0.ts]
+export function foo() { return "foo"; }
+
+//// [1.ts]
+var x = import { foo } from './0';
+
+//// [0.js]
+export function foo() { return "foo"; }
+//// [1.js]
+var x = ;
diff --git a/tests/cases/conformance/dynamicImport/importCallExpressionIncorrect1.ts b/tests/cases/conformance/dynamicImport/importCallExpressionIncorrect1.ts
new file mode 100644
index 00000000000..25a96ef30c6
--- /dev/null
+++ b/tests/cases/conformance/dynamicImport/importCallExpressionIncorrect1.ts
@@ -0,0 +1,8 @@
+// @module: esnext
+// @target: esnext
+// @filename: 0.ts
+export function foo() { return "foo"; }
+
+// @filename: 1.ts
+import
+import { foo } from './0';
\ No newline at end of file
diff --git a/tests/cases/conformance/dynamicImport/importCallExpressionIncorrect2.ts b/tests/cases/conformance/dynamicImport/importCallExpressionIncorrect2.ts
new file mode 100644
index 00000000000..01309b71ba2
--- /dev/null
+++ b/tests/cases/conformance/dynamicImport/importCallExpressionIncorrect2.ts
@@ -0,0 +1,7 @@
+// @module: esnext
+// @target: esnext
+// @filename: 0.ts
+export function foo() { return "foo"; }
+
+// @filename: 1.ts
+var x = import { foo } from './0';
\ No newline at end of file
diff --git a/tests/cases/fourslash/incrementalParsingDynamicImport2.ts b/tests/cases/fourslash/incrementalParsingDynamicImport2.ts
new file mode 100644
index 00000000000..f985894c5b0
--- /dev/null
+++ b/tests/cases/fourslash/incrementalParsingDynamicImport2.ts
@@ -0,0 +1,13 @@
+/// <reference path="fourslash.ts"/>
+
+// @lib: es2015
+
+// @Filename: ./foo.ts
+//// export function bar() { return 1; }
+
+// @Filename: ./0.ts
+//// /*1*/ import { bar } from "./foo"
+verify.numberOfErrorsInCurrentFile(0);
+goTo.marker("1");
+edit.insert("var x = ");
+verify.numberOfErrorsInCurrentFile(1);
\ No newline at end of file
diff --git a/tests/cases/fourslash/incrementalParsingDynamicImport3.ts b/tests/cases/fourslash/incrementalParsingDynamicImport3.ts
new file mode 100644
index 00000000000..b3da4c5b538
--- /dev/null
+++ b/tests/cases/fourslash/incrementalParsingDynamicImport3.ts
@@ -0,0 +1,14 @@
+/// <reference path="fourslash.ts"/>
+
+// @lib: es2015
+
+// @Filename: ./foo.ts
+//// export function bar() { return 1; }
+
+// @Filename: ./0.ts
+//// var x = import/*1*/
+
+verify.numberOfErrorsInCurrentFile(0);
+goTo.marker("1");
+edit.insert("(");
+verify.numberOfErrorsInCurrentFile(2);
\ No newline at end of file
diff --git a/tests/cases/fourslash/incrementalParsingDynamicImport4.ts b/tests/cases/fourslash/incrementalParsingDynamicImport4.ts
new file mode 100644
index 00000000000..f4b3960262d
--- /dev/null
+++ b/tests/cases/fourslash/incrementalParsingDynamicImport4.ts
@@ -0,0 +1,15 @@
+/// <reference path="fourslash.ts"/>
+
+// @lib: es2015
+
+// @Filename: ./foo.ts
+//// export function bar() { return 1; }
+
+// @Filename: ./0.ts
+//// /*1*/
+//// import { bar } from "./foo"
+
+verify.numberOfErrorsInCurrentFile(0);
+goTo.marker("1");
+edit.insert("import");
+verify.numberOfErrorsInCurrentFile(1);
\ No newline at end of file