Address PR: don't early exit when there are grammar errors

Author: Yui T

src/compiler/checker.ts

@@ -16099,15 +16099,22 @@ namespace ts {
 
         function checkImportCallExpression(node: ImportCall): Type {
             // Check grammar of dynamic import
-            if (checkGrammarArguments(node, node.arguments) || checkGrammarImportCallExpression(node)) {
+            checkGrammarArguments(node, node.arguments) || checkGrammarImportCallExpression(node);
+
+            if (node.arguments.length === 0) {
                 return createPromiseReturnType(node, anyType);
             }
-
             const specifier = node.arguments[0];
-            const specifierType = checkNonNullExpression(specifier);
-            if (!isTypeAssignableTo(specifierType, stringType)) {
+            const specifierType = checkExpressionCached(specifier);
+            // Even though multiple arugments is grammatically incorrect, type-check extra arguments for completion
+            for (let i = 1; i < node.arguments.length; ++i) {
+                checkExpressionCached(node.arguments[i]);
+            }
+
+            if (specifierType.flags & TypeFlags.Undefined || specifierType.flags & TypeFlags.Null || !isTypeAssignableTo(specifierType, stringType)) {
                 error(specifier, Diagnostics.Dynamic_import_s_specifier_must_be_of_type_string_but_here_has_type_0, typeToString(specifierType));
             }
+
             // resolveExternalModuleName will return undefined if the moduleReferenceExpression is not a string literal
             const moduleSymbol = resolveExternalModuleName(node, specifier);
             if (moduleSymbol) {

tests/baselines/reference/importCallExpression5ES2018.errors.txt

@@ -1,7 +1,7 @@
-tests/cases/conformance/es2018/dynamicImport/2.ts(3,23): error TS2532: Object is possibly 'undefined'.
-tests/cases/conformance/es2018/dynamicImport/2.ts(4,24): error TS2532: Object is possibly 'undefined'.
-tests/cases/conformance/es2018/dynamicImport/2.ts(5,24): error TS2531: Object is possibly 'null'.
-tests/cases/conformance/es2018/dynamicImport/2.ts(6,24): error TS2531: Object is possibly 'null'.
+tests/cases/conformance/es2018/dynamicImport/2.ts(3,23): error TS7036: Dynamic import's specifier must be of type 'string', but here has type '"./0" | undefined'.
+tests/cases/conformance/es2018/dynamicImport/2.ts(4,24): error TS7036: Dynamic import's specifier must be of type 'string', but here has type 'undefined'.
+tests/cases/conformance/es2018/dynamicImport/2.ts(5,24): error TS7036: Dynamic import's specifier must be of type 'string', but here has type '"./1" | null'.
+tests/cases/conformance/es2018/dynamicImport/2.ts(6,24): error TS7036: Dynamic import's specifier must be of type 'string', but here has type 'null'.
 
 
 ==== tests/cases/conformance/es2018/dynamicImport/0.ts (0 errors) ====
@@ -19,13 +19,13 @@ tests/cases/conformance/es2018/dynamicImport/2.ts(6,24): error TS2531: Object is
     const specify = bar() ? "./0" : undefined;
     let myModule = import(specify);
                           ~~~~~~~
-!!! error TS2532: Object is possibly 'undefined'.
+!!! error TS7036: Dynamic import's specifier must be of type 'string', but here has type '"./0" | undefined'.
     let myModule1 = import(undefined);
                            ~~~~~~~~~
-!!! error TS2532: Object is possibly 'undefined'.
+!!! error TS7036: Dynamic import's specifier must be of type 'string', but here has type 'undefined'.
     let myModule2 = import(bar() ? "./1" : null);
                            ~~~~~~~~~~~~~~~~~~~~
-!!! error TS2531: Object is possibly 'null'.
+!!! error TS7036: Dynamic import's specifier must be of type 'string', but here has type '"./1" | null'.
     let myModule3 = import(null);
                            ~~~~
-!!! error TS2531: Object is possibly 'null'.
+!!! error TS7036: Dynamic import's specifier must be of type 'string', but here has type 'null'.

tests/baselines/reference/importCallExpression6ES2018.errors.txt

@@ -1,5 +1,5 @@
-tests/cases/conformance/es2018/dynamicImport/2.ts(4,24): error TS2532: Object is possibly 'undefined'.
-tests/cases/conformance/es2018/dynamicImport/2.ts(6,24): error TS2531: Object is possibly 'null'.
+tests/cases/conformance/es2018/dynamicImport/2.ts(4,24): error TS7036: Dynamic import's specifier must be of type 'string', but here has type 'undefined'.
+tests/cases/conformance/es2018/dynamicImport/2.ts(6,24): error TS7036: Dynamic import's specifier must be of type 'string', but here has type 'null'.
 
 
 ==== tests/cases/conformance/es2018/dynamicImport/0.ts (0 errors) ====
@@ -18,8 +18,8 @@ tests/cases/conformance/es2018/dynamicImport/2.ts(6,24): error TS2531: Object is
     let myModule = import(specify);
     let myModule1 = import(undefined);
                            ~~~~~~~~~
-!!! error TS2532: Object is possibly 'undefined'.
+!!! error TS7036: Dynamic import's specifier must be of type 'string', but here has type 'undefined'.
     let myModule2 = import(bar() ? "./1" : null);
     let myModule3 = import(null);
                            ~~~~
-!!! error TS2531: Object is possibly 'null'.
+!!! error TS7036: Dynamic import's specifier must be of type 'string', but here has type 'null'.

tests/baselines/reference/importCallExpressionGrammarError.errors.txt

@@ -2,10 +2,12 @@ tests/cases/conformance/es2018/dynamicImport/importCallExpressionGrammarError.ts
 tests/cases/conformance/es2018/dynamicImport/importCallExpressionGrammarError.ts(7,17): error TS1325: Specifier of dynamic import cannot be spread element.
 tests/cases/conformance/es2018/dynamicImport/importCallExpressionGrammarError.ts(8,12): error TS1324: Dynamic import must have one specifier as an argument.
 tests/cases/conformance/es2018/dynamicImport/importCallExpressionGrammarError.ts(9,19): error TS1135: Argument expression expected.
+tests/cases/conformance/es2018/dynamicImport/importCallExpressionGrammarError.ts(9,19): error TS7036: Dynamic import's specifier must be of type 'string', but here has type 'undefined'.
 tests/cases/conformance/es2018/dynamicImport/importCallExpressionGrammarError.ts(10,12): error TS1324: Dynamic import must have one specifier as an argument.
+tests/cases/conformance/es2018/dynamicImport/importCallExpressionGrammarError.ts(10,19): error TS2307: Cannot find module 'pathToModule'.
 
 
-==== tests/cases/conformance/es2018/dynamicImport/importCallExpressionGrammarError.ts (5 errors) ====
+==== tests/cases/conformance/es2018/dynamicImport/importCallExpressionGrammarError.ts (7 errors) ====
     declare function getSpecifier(): string;
     declare var whatToLoad: boolean;
 
@@ -23,6 +25,10 @@ tests/cases/conformance/es2018/dynamicImport/importCallExpressionGrammarError.ts
     const p3 = import(,);
 
 !!! error TS1135: Argument expression expected.
+                      
+!!! error TS7036: Dynamic import's specifier must be of type 'string', but here has type 'undefined'.
     const p4 = import("pathToModule", "secondModule");
                ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-!!! error TS1324: Dynamic import must have one specifier as an argument.
+!!! error TS1324: Dynamic import must have one specifier as an argument.
+                      ~~~~~~~~~~~~~~
+!!! error TS2307: Cannot find module 'pathToModule'.