Better error message for mistaken import (#40)

Issue number of the reported bug or feature request: microsoft#13601

Author: prime-optimus

src/compiler/checker.ts

@@ -2202,7 +2202,18 @@ namespace ts {
                         ));
                     }
                     else {
-                        error(node.name, Diagnostics.Module_0_has_no_default_export, symbolToString(moduleSymbol));
+                        if (moduleSymbol.exports && moduleSymbol.exports.has(node.symbol.escapedName)) {
+                            error(
+                                node.name,
+                                Diagnostics.Module_0_has_no_default_export_Did_you_mean_to_use_import_1_from_0_instead,
+                                symbolToString(moduleSymbol),
+                                symbolToString(node.symbol),
+                            );
+                        }
+                        else {
+                            error(node.name, Diagnostics.Module_0_has_no_default_export, symbolToString(moduleSymbol));
+                        }
+
                     }
                 }
                 else if (hasSyntheticDefault) {
@@ -2310,7 +2321,17 @@ namespace ts {
                             }
                         }
                         else {
-                            error(name, Diagnostics.Module_0_has_no_exported_member_1, moduleName, declarationName);
+                            if (moduleSymbol.exports && moduleSymbol.exports.has(InternalSymbolName.Default)) {
+                                error(
+                                    name,
+                                    Diagnostics.Module_0_has_no_exported_member_1_Did_you_mean_to_use_import_1_from_0_instead,
+                                    moduleName,
+                                    declarationName
+                                );
+                            }
+                            else {
+                                error(name, Diagnostics.Module_0_has_no_exported_member_1, moduleName, declarationName);
+                            }
                         }
                     }
                     return symbol;

src/compiler/diagnosticMessages.json

@@ -1043,6 +1043,14 @@
         "category": "Error",
         "code": 1358
     },
+    "Module '{0}' has no default export. Did you mean to use 'import { {1} } from {0}' instead?": {
+        "category": "Error",
+        "code": 1359
+    },
+    "Module '{0}' has no exported member '{1}'. Did you mean to use 'import {1} from {0}' instead?": {
+        "category": "Error",
+        "code": 1360
+    },
 
     "The types of '{0}' are incompatible between these types.": {
         "category": "Error",

tests/baselines/reference/decoratorMetadataWithImportDeclarationNameCollision4.errors.txt

@@ -1,4 +1,4 @@
-tests/cases/compiler/service.ts(1,8): error TS1192: Module '"tests/cases/compiler/db"' has no default export.
+tests/cases/compiler/service.ts(1,8): error TS1359: Module '"tests/cases/compiler/db"' has no default export. Did you mean to use 'import { db } from "tests/cases/compiler/db"' instead?
 
 
 ==== tests/cases/compiler/db.ts (0 errors) ====
@@ -10,7 +10,7 @@ tests/cases/compiler/service.ts(1,8): error TS1192: Module '"tests/cases/compile
 ==== tests/cases/compiler/service.ts (1 errors) ====
     import db from './db'; // error no default export
            ~~
-!!! error TS1192: Module '"tests/cases/compiler/db"' has no default export.
+!!! error TS1359: Module '"tests/cases/compiler/db"' has no default export. Did you mean to use 'import { db } from "tests/cases/compiler/db"' instead?
     function someDecorator(target) {
         return target;
     }

tests/baselines/reference/es6ImportDefaultBindingFollowedWithNamedImport1.errors.txt

@@ -1,9 +1,9 @@
-tests/cases/compiler/es6ImportDefaultBindingFollowedWithNamedImport1_1.ts(3,27): error TS2305: Module '"./es6ImportDefaultBindingFollowedWithNamedImport1_0"' has no exported member 'a'.
-tests/cases/compiler/es6ImportDefaultBindingFollowedWithNamedImport1_1.ts(5,27): error TS2305: Module '"./es6ImportDefaultBindingFollowedWithNamedImport1_0"' has no exported member 'a'.
-tests/cases/compiler/es6ImportDefaultBindingFollowedWithNamedImport1_1.ts(7,27): error TS2305: Module '"./es6ImportDefaultBindingFollowedWithNamedImport1_0"' has no exported member 'x'.
-tests/cases/compiler/es6ImportDefaultBindingFollowedWithNamedImport1_1.ts(7,30): error TS2305: Module '"./es6ImportDefaultBindingFollowedWithNamedImport1_0"' has no exported member 'a'.
-tests/cases/compiler/es6ImportDefaultBindingFollowedWithNamedImport1_1.ts(9,27): error TS2305: Module '"./es6ImportDefaultBindingFollowedWithNamedImport1_0"' has no exported member 'x'.
-tests/cases/compiler/es6ImportDefaultBindingFollowedWithNamedImport1_1.ts(11,27): error TS2305: Module '"./es6ImportDefaultBindingFollowedWithNamedImport1_0"' has no exported member 'm'.
+tests/cases/compiler/es6ImportDefaultBindingFollowedWithNamedImport1_1.ts(3,27): error TS1360: Module '"./es6ImportDefaultBindingFollowedWithNamedImport1_0"' has no exported member 'a'. Did you mean to use 'import a from "./es6ImportDefaultBindingFollowedWithNamedImport1_0"' instead?
+tests/cases/compiler/es6ImportDefaultBindingFollowedWithNamedImport1_1.ts(5,27): error TS1360: Module '"./es6ImportDefaultBindingFollowedWithNamedImport1_0"' has no exported member 'a'. Did you mean to use 'import a from "./es6ImportDefaultBindingFollowedWithNamedImport1_0"' instead?
+tests/cases/compiler/es6ImportDefaultBindingFollowedWithNamedImport1_1.ts(7,27): error TS1360: Module '"./es6ImportDefaultBindingFollowedWithNamedImport1_0"' has no exported member 'x'. Did you mean to use 'import x from "./es6ImportDefaultBindingFollowedWithNamedImport1_0"' instead?
+tests/cases/compiler/es6ImportDefaultBindingFollowedWithNamedImport1_1.ts(7,30): error TS1360: Module '"./es6ImportDefaultBindingFollowedWithNamedImport1_0"' has no exported member 'a'. Did you mean to use 'import a from "./es6ImportDefaultBindingFollowedWithNamedImport1_0"' instead?
+tests/cases/compiler/es6ImportDefaultBindingFollowedWithNamedImport1_1.ts(9,27): error TS1360: Module '"./es6ImportDefaultBindingFollowedWithNamedImport1_0"' has no exported member 'x'. Did you mean to use 'import x from "./es6ImportDefaultBindingFollowedWithNamedImport1_0"' instead?
+tests/cases/compiler/es6ImportDefaultBindingFollowedWithNamedImport1_1.ts(11,27): error TS1360: Module '"./es6ImportDefaultBindingFollowedWithNamedImport1_0"' has no exported member 'm'. Did you mean to use 'import m from "./es6ImportDefaultBindingFollowedWithNamedImport1_0"' instead?
 
 
 ==== tests/cases/compiler/es6ImportDefaultBindingFollowedWithNamedImport1_0.ts (0 errors) ====
@@ -15,24 +15,24 @@ tests/cases/compiler/es6ImportDefaultBindingFollowedWithNamedImport1_1.ts(11,27)
     var x1: number = defaultBinding1;
     import defaultBinding2, { a } from "es6ImportDefaultBindingFollowedWithNamedImport1_0";
                               ~
-!!! error TS2305: Module '"./es6ImportDefaultBindingFollowedWithNamedImport1_0"' has no exported member 'a'.
+!!! error TS1360: Module '"./es6ImportDefaultBindingFollowedWithNamedImport1_0"' has no exported member 'a'. Did you mean to use 'import a from "./es6ImportDefaultBindingFollowedWithNamedImport1_0"' instead?
     var x1: number = defaultBinding2;
     import defaultBinding3, { a as b } from "es6ImportDefaultBindingFollowedWithNamedImport1_0";
                               ~
-!!! error TS2305: Module '"./es6ImportDefaultBindingFollowedWithNamedImport1_0"' has no exported member 'a'.
+!!! error TS1360: Module '"./es6ImportDefaultBindingFollowedWithNamedImport1_0"' has no exported member 'a'. Did you mean to use 'import a from "./es6ImportDefaultBindingFollowedWithNamedImport1_0"' instead?
     var x1: number = defaultBinding3;
     import defaultBinding4, { x, a as y } from "es6ImportDefaultBindingFollowedWithNamedImport1_0";
                               ~
-!!! error TS2305: Module '"./es6ImportDefaultBindingFollowedWithNamedImport1_0"' has no exported member 'x'.
+!!! error TS1360: Module '"./es6ImportDefaultBindingFollowedWithNamedImport1_0"' has no exported member 'x'. Did you mean to use 'import x from "./es6ImportDefaultBindingFollowedWithNamedImport1_0"' instead?
                                  ~
-!!! error TS2305: Module '"./es6ImportDefaultBindingFollowedWithNamedImport1_0"' has no exported member 'a'.
+!!! error TS1360: Module '"./es6ImportDefaultBindingFollowedWithNamedImport1_0"' has no exported member 'a'. Did you mean to use 'import a from "./es6ImportDefaultBindingFollowedWithNamedImport1_0"' instead?
     var x1: number = defaultBinding4;
     import defaultBinding5, { x as z,  } from "es6ImportDefaultBindingFollowedWithNamedImport1_0";
                               ~
-!!! error TS2305: Module '"./es6ImportDefaultBindingFollowedWithNamedImport1_0"' has no exported member 'x'.
+!!! error TS1360: Module '"./es6ImportDefaultBindingFollowedWithNamedImport1_0"' has no exported member 'x'. Did you mean to use 'import x from "./es6ImportDefaultBindingFollowedWithNamedImport1_0"' instead?
     var x1: number = defaultBinding5;
     import defaultBinding6, { m,  } from "es6ImportDefaultBindingFollowedWithNamedImport1_0";
                               ~
-!!! error TS2305: Module '"./es6ImportDefaultBindingFollowedWithNamedImport1_0"' has no exported member 'm'.
+!!! error TS1360: Module '"./es6ImportDefaultBindingFollowedWithNamedImport1_0"' has no exported member 'm'. Did you mean to use 'import m from "./es6ImportDefaultBindingFollowedWithNamedImport1_0"' instead?
     var x1: number = defaultBinding6;
 

tests/baselines/reference/es6ImportDefaultBindingFollowedWithNamedImport1InEs5.errors.txt

@@ -1,9 +1,9 @@
-tests/cases/compiler/es6ImportDefaultBindingFollowedWithNamedImport1InEs5_1.ts(3,27): error TS2305: Module '"./es6ImportDefaultBindingFollowedWithNamedImport1InEs5_0"' has no exported member 'a'.
-tests/cases/compiler/es6ImportDefaultBindingFollowedWithNamedImport1InEs5_1.ts(5,27): error TS2305: Module '"./es6ImportDefaultBindingFollowedWithNamedImport1InEs5_0"' has no exported member 'a'.
-tests/cases/compiler/es6ImportDefaultBindingFollowedWithNamedImport1InEs5_1.ts(7,27): error TS2305: Module '"./es6ImportDefaultBindingFollowedWithNamedImport1InEs5_0"' has no exported member 'x'.
-tests/cases/compiler/es6ImportDefaultBindingFollowedWithNamedImport1InEs5_1.ts(7,30): error TS2305: Module '"./es6ImportDefaultBindingFollowedWithNamedImport1InEs5_0"' has no exported member 'a'.
-tests/cases/compiler/es6ImportDefaultBindingFollowedWithNamedImport1InEs5_1.ts(9,27): error TS2305: Module '"./es6ImportDefaultBindingFollowedWithNamedImport1InEs5_0"' has no exported member 'x'.
-tests/cases/compiler/es6ImportDefaultBindingFollowedWithNamedImport1InEs5_1.ts(11,27): error TS2305: Module '"./es6ImportDefaultBindingFollowedWithNamedImport1InEs5_0"' has no exported member 'm'.
+tests/cases/compiler/es6ImportDefaultBindingFollowedWithNamedImport1InEs5_1.ts(3,27): error TS1360: Module '"./es6ImportDefaultBindingFollowedWithNamedImport1InEs5_0"' has no exported member 'a'. Did you mean to use 'import a from "./es6ImportDefaultBindingFollowedWithNamedImport1InEs5_0"' instead?
+tests/cases/compiler/es6ImportDefaultBindingFollowedWithNamedImport1InEs5_1.ts(5,27): error TS1360: Module '"./es6ImportDefaultBindingFollowedWithNamedImport1InEs5_0"' has no exported member 'a'. Did you mean to use 'import a from "./es6ImportDefaultBindingFollowedWithNamedImport1InEs5_0"' instead?
+tests/cases/compiler/es6ImportDefaultBindingFollowedWithNamedImport1InEs5_1.ts(7,27): error TS1360: Module '"./es6ImportDefaultBindingFollowedWithNamedImport1InEs5_0"' has no exported member 'x'. Did you mean to use 'import x from "./es6ImportDefaultBindingFollowedWithNamedImport1InEs5_0"' instead?
+tests/cases/compiler/es6ImportDefaultBindingFollowedWithNamedImport1InEs5_1.ts(7,30): error TS1360: Module '"./es6ImportDefaultBindingFollowedWithNamedImport1InEs5_0"' has no exported member 'a'. Did you mean to use 'import a from "./es6ImportDefaultBindingFollowedWithNamedImport1InEs5_0"' instead?
+tests/cases/compiler/es6ImportDefaultBindingFollowedWithNamedImport1InEs5_1.ts(9,27): error TS1360: Module '"./es6ImportDefaultBindingFollowedWithNamedImport1InEs5_0"' has no exported member 'x'. Did you mean to use 'import x from "./es6ImportDefaultBindingFollowedWithNamedImport1InEs5_0"' instead?
+tests/cases/compiler/es6ImportDefaultBindingFollowedWithNamedImport1InEs5_1.ts(11,27): error TS1360: Module '"./es6ImportDefaultBindingFollowedWithNamedImport1InEs5_0"' has no exported member 'm'. Did you mean to use 'import m from "./es6ImportDefaultBindingFollowedWithNamedImport1InEs5_0"' instead?
 
 
 ==== tests/cases/compiler/es6ImportDefaultBindingFollowedWithNamedImport1InEs5_0.ts (0 errors) ====
@@ -15,24 +15,24 @@ tests/cases/compiler/es6ImportDefaultBindingFollowedWithNamedImport1InEs5_1.ts(1
     var x: number = defaultBinding1;
     import defaultBinding2, { a } from "./es6ImportDefaultBindingFollowedWithNamedImport1InEs5_0";
                               ~
-!!! error TS2305: Module '"./es6ImportDefaultBindingFollowedWithNamedImport1InEs5_0"' has no exported member 'a'.
+!!! error TS1360: Module '"./es6ImportDefaultBindingFollowedWithNamedImport1InEs5_0"' has no exported member 'a'. Did you mean to use 'import a from "./es6ImportDefaultBindingFollowedWithNamedImport1InEs5_0"' instead?
     var x: number = defaultBinding2;
     import defaultBinding3, { a as b } from "./es6ImportDefaultBindingFollowedWithNamedImport1InEs5_0";
                               ~
-!!! error TS2305: Module '"./es6ImportDefaultBindingFollowedWithNamedImport1InEs5_0"' has no exported member 'a'.
+!!! error TS1360: Module '"./es6ImportDefaultBindingFollowedWithNamedImport1InEs5_0"' has no exported member 'a'. Did you mean to use 'import a from "./es6ImportDefaultBindingFollowedWithNamedImport1InEs5_0"' instead?
     var x: number = defaultBinding3;
     import defaultBinding4, { x, a as y } from "./es6ImportDefaultBindingFollowedWithNamedImport1InEs5_0";
                               ~
-!!! error TS2305: Module '"./es6ImportDefaultBindingFollowedWithNamedImport1InEs5_0"' has no exported member 'x'.
+!!! error TS1360: Module '"./es6ImportDefaultBindingFollowedWithNamedImport1InEs5_0"' has no exported member 'x'. Did you mean to use 'import x from "./es6ImportDefaultBindingFollowedWithNamedImport1InEs5_0"' instead?
                                  ~
-!!! error TS2305: Module '"./es6ImportDefaultBindingFollowedWithNamedImport1InEs5_0"' has no exported member 'a'.
+!!! error TS1360: Module '"./es6ImportDefaultBindingFollowedWithNamedImport1InEs5_0"' has no exported member 'a'. Did you mean to use 'import a from "./es6ImportDefaultBindingFollowedWithNamedImport1InEs5_0"' instead?
     var x: number = defaultBinding4;
     import defaultBinding5, { x as z,  } from "./es6ImportDefaultBindingFollowedWithNamedImport1InEs5_0";
                               ~
-!!! error TS2305: Module '"./es6ImportDefaultBindingFollowedWithNamedImport1InEs5_0"' has no exported member 'x'.
+!!! error TS1360: Module '"./es6ImportDefaultBindingFollowedWithNamedImport1InEs5_0"' has no exported member 'x'. Did you mean to use 'import x from "./es6ImportDefaultBindingFollowedWithNamedImport1InEs5_0"' instead?
     var x: number = defaultBinding5;
     import defaultBinding6, { m,  } from "./es6ImportDefaultBindingFollowedWithNamedImport1InEs5_0";
                               ~
-!!! error TS2305: Module '"./es6ImportDefaultBindingFollowedWithNamedImport1InEs5_0"' has no exported member 'm'.
+!!! error TS1360: Module '"./es6ImportDefaultBindingFollowedWithNamedImport1InEs5_0"' has no exported member 'm'. Did you mean to use 'import m from "./es6ImportDefaultBindingFollowedWithNamedImport1InEs5_0"' instead?
     var x: number = defaultBinding6;