Merge pull request #16633 from Microsoft/release-2.4_fixIncrementalParsing

[Release 2.4] Port fix incremental parsing PR

Author: yuit

src/compiler/parser.ts

@@ -3700,7 +3700,7 @@ 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

src/compiler/program.ts

@@ -802,6 +802,10 @@ 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

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.

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 ;

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.

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 = ;

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';

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';

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);

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);