diff --git a/tests/language/loop/for_in3_test.dart b/tests/language/loop/for_in3_test.dart
index 7de80496e4d..b03e6be81f2 100644
--- a/tests/language/loop/for_in3_test.dart
+++ b/tests/language/loop/for_in3_test.dart
@@ -6,5 +6,8 @@
 
 main() {
   var chars = [];
-  for (var c in "foo") chars.add(c); /*@compile-error=unspecified*/
+  for (var c in "foo") chars.add(c);
+  //            ^^^^^
+  // [analyzer] COMPILE_TIME_ERROR.FOR_IN_OF_INVALID_TYPE
+  // [cfe] The type 'String' used in the 'for' loop must implement 'Iterable<dynamic>'.
 }
diff --git a/tests/language/main/not_a_function_test.dart b/tests/language/main/not_a_function_test.dart
index 62ab4ccb86a..a57fa7f43da 100644
--- a/tests/language/main/not_a_function_test.dart
+++ b/tests/language/main/not_a_function_test.dart
@@ -4,4 +4,9 @@
 
 main() {}
 
-var main; /*@compile-error=unspecified*/
+var main;
+//  ^^^^
+// [analyzer] COMPILE_TIME_ERROR.DUPLICATE_DEFINITION
+// [analyzer] COMPILE_TIME_ERROR.MAIN_IS_NOT_FUNCTION
+// [cfe] 'main' is already declared in this scope.
+// [cfe] The 'main' declaration must be a function declaration.
diff --git a/tests/language/malbounded/type_cast2_test.dart b/tests/language/malbounded/type_cast2_test.dart
index 06940a8e958..2f3a41788f3 100644
--- a/tests/language/malbounded/type_cast2_test.dart
+++ b/tests/language/malbounded/type_cast2_test.dart
@@ -8,7 +8,11 @@ class A<T extends num> {}
 
 class B<T> {
   test() {
-    new A() as A<T>; /*@compile-error=unspecified*/
+    new A() as A<T>;
+    //         ^
+    // [cfe] Type argument 'T' doesn't conform to the bound 'num' of the type variable 'T' on 'A'.
+    //           ^
+    // [analyzer] COMPILE_TIME_ERROR.TYPE_ARGUMENT_NOT_MATCHING_BOUNDS
   }
 }
 
diff --git a/tests/language/malformed/type_test.dart b/tests/language/malformed/type_test.dart
index b464d6eed97..f54cb3fdfce 100644
--- a/tests/language/malformed/type_test.dart
+++ b/tests/language/malformed/type_test.dart
@@ -3,7 +3,11 @@
 // BSD-style license that can be found in the LICENSE file.
 
 null_() => null;
-final Undeclared/*@compile-error=unspecified*/ x = null_();
+final Undeclared x = null_();
+//    ^^^^^^^^^^
+// [analyzer] COMPILE_TIME_ERROR.UNDEFINED_CLASS
+// [cfe] 'Undeclared' isn't a type.
+// [cfe] Type 'Undeclared' not found.
 
 main() {
   print(x);
diff --git a/tests/language/mixin/with_two_implicit_constructors_test.dart b/tests/language/mixin/with_two_implicit_constructors_test.dart
index 198461b9185..8fcf3eaeb72 100644
--- a/tests/language/mixin/with_two_implicit_constructors_test.dart
+++ b/tests/language/mixin/with_two_implicit_constructors_test.dart
@@ -10,11 +10,14 @@ class A {
   A() : field = 2;
 }
 
-class Mixin {}
+mixin Mixin {}
 
 class B extends A with Mixin {}
 
 main() {
   Expect.equals(2, new B().field);
-  new B.bar(); /*@compile-error=unspecified*/
+  new B.bar();
+  //    ^^^
+  // [analyzer] COMPILE_TIME_ERROR.NEW_WITH_UNDEFINED_CONSTRUCTOR
+  // [cfe] Couldn't find constructor 'B.bar'.
 }
diff --git a/tests/language/mixin_declaration/mixin_declaration_inference_invalid_00_test.dart b/tests/language/mixin_declaration/mixin_declaration_inference_invalid_00_test.dart
index 5d99d2f5c24..05eccb65717 100644
--- a/tests/language/mixin_declaration/mixin_declaration_inference_invalid_00_test.dart
+++ b/tests/language/mixin_declaration/mixin_declaration_inference_invalid_00_test.dart
@@ -11,6 +11,11 @@ mixin M0<T> on I<T> {}
 ///////////////////////////////////////////////////////
 
 // Error since class hierarchy is inconsistent
-class A00 extends I with M0<int> {} /*@compile-error=unspecified*/
+class A00 extends I with M0<int> {}
+//    ^
+// [cfe] 'I with M0' can't implement both 'I<dynamic>' and 'I<int>'
+// [cfe] 'I<dynamic>' doesn't implement 'I<int>' so it can't be used with 'M0<int>'.
+//                       ^^
+// [analyzer] COMPILE_TIME_ERROR.MIXIN_APPLICATION_NOT_IMPLEMENTED_INTERFACE
 
-void main() {}
\ No newline at end of file
+void main() {}
diff --git a/tests/language/mixin_declaration/mixin_declaration_inference_invalid_01_test.dart b/tests/language/mixin_declaration/mixin_declaration_inference_invalid_01_test.dart
index 749d8134628..551adec9745 100644
--- a/tests/language/mixin_declaration/mixin_declaration_inference_invalid_01_test.dart
+++ b/tests/language/mixin_declaration/mixin_declaration_inference_invalid_01_test.dart
@@ -13,6 +13,11 @@ mixin M1<T> on I<T> {}
 ///////////////////////////////////////////////////////
 
 // Error since class hierarchy is inconsistent
-class A00 extends I with M0, M1<int> {} /*@compile-error=unspecified*/
+class A00 extends I with M0, M1<int> {}
+//    ^
+// [cfe] 'I with M0, M1' can't implement both 'I<dynamic>' and 'I<int>'
+// [cfe] '_A00&I&M0' doesn't implement 'I<int>' so it can't be used with 'M1<int>'.
+//                           ^^
+// [analyzer] COMPILE_TIME_ERROR.MIXIN_APPLICATION_NOT_IMPLEMENTED_INTERFACE
 
-void main() {}
\ No newline at end of file
+void main() {}
diff --git a/tests/language/mixin_declaration/mixin_declaration_inference_invalid_02_test.dart b/tests/language/mixin_declaration/mixin_declaration_inference_invalid_02_test.dart
index 01ae1ae6688..d08f401b98b 100644
--- a/tests/language/mixin_declaration/mixin_declaration_inference_invalid_02_test.dart
+++ b/tests/language/mixin_declaration/mixin_declaration_inference_invalid_02_test.dart
@@ -13,6 +13,11 @@ mixin M1<T> on I<T> {}
 ///////////////////////////////////////////////////////
 
 // Error since class hierarchy is inconsistent
-class A00 with M0, M1<int> {} /*@compile-error=unspecified*/
+class A00 with M0, M1<int> {}
+//    ^
+// [cfe] 'Object with M0, M1' can't implement both 'I<dynamic>' and 'I<int>'
+// [cfe] '_A00&Object&M0' doesn't implement 'I<int>' so it can't be used with 'M1<int>'.
+//                 ^^
+// [analyzer] COMPILE_TIME_ERROR.MIXIN_APPLICATION_NOT_IMPLEMENTED_INTERFACE
 
-void main() {}
\ No newline at end of file
+void main() {}
diff --git a/tests/language/mixin_declaration/mixin_declaration_inference_invalid_03_test.dart b/tests/language/mixin_declaration/mixin_declaration_inference_invalid_03_test.dart
index 574170024c8..d10d26180a5 100644
--- a/tests/language/mixin_declaration/mixin_declaration_inference_invalid_03_test.dart
+++ b/tests/language/mixin_declaration/mixin_declaration_inference_invalid_03_test.dart
@@ -11,6 +11,9 @@ mixin M0<T> implements I<T> {}
 ///////////////////////////////////////////////////////
 
 // Error since class hierarchy is inconsistent
-class A00 extends Object with M0 implements I<int> {} /*@compile-error=unspecified*/
+class A00 extends Object with M0 implements I<int> {}
+//    ^^^
+// [analyzer] COMPILE_TIME_ERROR.CONFLICTING_GENERIC_INTERFACES
+// [cfe] 'A00' can't implement both 'I<dynamic>' and 'I<int>'
 
-void main() {}
\ No newline at end of file
+void main() {}
diff --git a/tests/language/mixin_declaration/mixin_declaration_inference_invalid_04_test.dart b/tests/language/mixin_declaration/mixin_declaration_inference_invalid_04_test.dart
index 50d017b9e03..29531fc5dff 100644
--- a/tests/language/mixin_declaration/mixin_declaration_inference_invalid_04_test.dart
+++ b/tests/language/mixin_declaration/mixin_declaration_inference_invalid_04_test.dart
@@ -11,6 +11,9 @@ mixin M0<T> implements I<T> {}
 ///////////////////////////////////////////////////////
 
 // Error since class hierarchy is inconsistent
-class A00 with M0 implements I<int> {} /*@compile-error=unspecified*/
+class A00 with M0 implements I<int> {}
+//    ^^^
+// [analyzer] COMPILE_TIME_ERROR.CONFLICTING_GENERIC_INTERFACES
+// [cfe] 'A00' can't implement both 'I<dynamic>' and 'I<int>'
 
-void main() {}
\ No newline at end of file
+void main() {}
diff --git a/tests/language/mixin_declaration/mixin_declaration_inference_invalid_05_test.dart b/tests/language/mixin_declaration/mixin_declaration_inference_invalid_05_test.dart
index 38e681e561b..14986e3806a 100644
--- a/tests/language/mixin_declaration/mixin_declaration_inference_invalid_05_test.dart
+++ b/tests/language/mixin_declaration/mixin_declaration_inference_invalid_05_test.dart
@@ -13,6 +13,9 @@ mixin M1<T> implements I<T> {}
 ///////////////////////////////////////////////////////
 
 // Error since class hierarchy is inconsistent
-class A00 extends I<int> with M0<int>, M1 {} /*@compile-error=unspecified*/
+class A00 extends I<int> with M0<int>, M1 {}
+//    ^^^
+// [analyzer] COMPILE_TIME_ERROR.CONFLICTING_GENERIC_INTERFACES
+// [cfe] 'I with M0, M1' can't implement both 'I<int>' and 'I<dynamic>'
 
-void main() {}
\ No newline at end of file
+void main() {}
diff --git a/tests/language/mixin_declaration/mixin_declaration_inference_invalid_06_test.dart b/tests/language/mixin_declaration/mixin_declaration_inference_invalid_06_test.dart
index 14c2416d92f..7e63c63db10 100644
--- a/tests/language/mixin_declaration/mixin_declaration_inference_invalid_06_test.dart
+++ b/tests/language/mixin_declaration/mixin_declaration_inference_invalid_06_test.dart
@@ -3,6 +3,7 @@
 // BSD-style license that can be found in the LICENSE file.
 
 class I<X> {}
+
 class J<X> {}
 
 mixin M0<S, T> implements I<S>, J<T> {}
@@ -14,10 +15,21 @@ mixin M1<S, T> implements I<S>, J<T> {}
 ///////////////////////////////////////////////////////
 
 class A00 extends I<int> with M0 {}
+//    ^^^
+// [analyzer] COMPILE_TIME_ERROR.CONFLICTING_GENERIC_INTERFACES
+// [cfe] 'I with M0' can't implement both 'I<int>' and 'I<dynamic>'
 
 class A01 extends J<int> with M1 {}
+//    ^^^
+// [analyzer] COMPILE_TIME_ERROR.CONFLICTING_GENERIC_INTERFACES
+// [cfe] 'J with M1' can't implement both 'J<int>' and 'J<dynamic>'
 
 // Error since class hierarchy is inconsistent
-class A02 extends A00 implements A01 {} /*@compile-error=unspecified*/
+class A02 extends A00 implements A01 {}
+//    ^^^
+// [analyzer] COMPILE_TIME_ERROR.CONFLICTING_GENERIC_INTERFACES
+// [analyzer] COMPILE_TIME_ERROR.CONFLICTING_GENERIC_INTERFACES
+// [cfe] 'A02' can't implement both 'I<int>' and 'I<dynamic>'
+// [cfe] 'A02' can't implement both 'J<dynamic>' and 'J<int>'
 
-void main() {}
\ No newline at end of file
+void main() {}
diff --git a/tests/language/mixin_declaration/mixin_declaration_inference_invalid_07_test.dart b/tests/language/mixin_declaration/mixin_declaration_inference_invalid_07_test.dart
index 9b16c66ad89..a3f100978f0 100644
--- a/tests/language/mixin_declaration/mixin_declaration_inference_invalid_07_test.dart
+++ b/tests/language/mixin_declaration/mixin_declaration_inference_invalid_07_test.dart
@@ -14,6 +14,9 @@ class M1 implements I<int> {}
 
 // M0 is inferred as M0<int, Comparable<dynamic>>
 // Error since super-bounded type not allowed
-class A extends M1 with M0 {} /*@compile-error=unspecified*/
+class A extends M1 with M0 {}
+//                      ^^
+// [analyzer] COMPILE_TIME_ERROR.TYPE_ARGUMENT_NOT_MATCHING_BOUNDS
+// [cfe] Inferred type argument 'Comparable<dynamic>' doesn't conform to the bound 'Comparable<Y>' of the type variable 'Y' on 'M0'.
 
-void main() {}
\ No newline at end of file
+void main() {}
diff --git a/tests/language/mixin_declaration/mixin_declaration_inference_invalid_08_test.dart b/tests/language/mixin_declaration/mixin_declaration_inference_invalid_08_test.dart
index 23da50d3057..7dac44808fa 100644
--- a/tests/language/mixin_declaration/mixin_declaration_inference_invalid_08_test.dart
+++ b/tests/language/mixin_declaration/mixin_declaration_inference_invalid_08_test.dart
@@ -12,10 +12,12 @@ mixin M1<T> implements I<String, T> {}
 // Inference is not bi-directional
 ///////////////////////////////////////////////////////
 
-
 // M0<String>, M1<int> is a solution, but we shouldn't find it
 // M0 inferred as M0<dynamic>
 // M1 inferred as M1<dynamic>
-class A with M0, M1 {} /*@compile-error=unspecified*/
+class A with M0, M1 {}
+//    ^
+// [analyzer] COMPILE_TIME_ERROR.CONFLICTING_GENERIC_INTERFACES
+// [cfe] 'Object with M0, M1' can't implement both 'I<dynamic, int>' and 'I<String, dynamic>'
 
-void main() {}
\ No newline at end of file
+void main() {}
diff --git a/tests/language/mixin_declaration/mixin_declaration_inference_invalid_09_test.dart b/tests/language/mixin_declaration/mixin_declaration_inference_invalid_09_test.dart
index 0ebdf97cd4a..8dad7015984 100644
--- a/tests/language/mixin_declaration/mixin_declaration_inference_invalid_09_test.dart
+++ b/tests/language/mixin_declaration/mixin_declaration_inference_invalid_09_test.dart
@@ -18,6 +18,9 @@ mixin M1<T> implements I<List<T>, T> {}
 // U0 = List<U1>
 // U1 = List<U0>
 // which has no finite solution
-class A with M0, M1 {} /*@compile-error=unspecified*/
+class A with M0, M1 {}
+//    ^
+// [analyzer] COMPILE_TIME_ERROR.CONFLICTING_GENERIC_INTERFACES
+// [cfe] 'Object with M0, M1' can't implement both 'I<dynamic, List<dynamic>>' and 'I<List<dynamic>, dynamic>'
 
-void main() {}
\ No newline at end of file
+void main() {}
diff --git a/tests/language/mixin_declaration/mixin_declaration_inference_invalid_10_test.dart b/tests/language/mixin_declaration/mixin_declaration_inference_invalid_10_test.dart
index 00563ef385f..cd7795f734c 100644
--- a/tests/language/mixin_declaration/mixin_declaration_inference_invalid_10_test.dart
+++ b/tests/language/mixin_declaration/mixin_declaration_inference_invalid_10_test.dart
@@ -2,14 +2,21 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-class I<T> {}
-class J<T> {}
+mixin I<T> {}
+
+mixin J<T> {}
+
 mixin M0<T> implements I<T>, J<T> {}
 
 //////////////////////////////////////////////////////
 // Over-constrained results are caught
 ///////////////////////////////////////////////////////
 
-class A with I<int>, J<double>, M0 {} /*@compile-error=unspecified*/
+class A with I<int>, J<double>, M0 {}
+//    ^
+// [analyzer] COMPILE_TIME_ERROR.CONFLICTING_GENERIC_INTERFACES
+// [analyzer] COMPILE_TIME_ERROR.CONFLICTING_GENERIC_INTERFACES
+// [cfe] 'Object with I, J, M0' can't implement both 'I<int>' and 'I<dynamic>'
+// [cfe] 'Object with I, J, M0' can't implement both 'J<double>' and 'J<dynamic>'
 
-void main() {}
\ No newline at end of file
+void main() {}
diff --git a/tests/language/mixin_declaration/mixin_declaration_inference_invalid_11_test.dart b/tests/language/mixin_declaration/mixin_declaration_inference_invalid_11_test.dart
index c7de81ee83c..40a962cb9c6 100644
--- a/tests/language/mixin_declaration/mixin_declaration_inference_invalid_11_test.dart
+++ b/tests/language/mixin_declaration/mixin_declaration_inference_invalid_11_test.dart
@@ -3,6 +3,7 @@
 // BSD-style license that can be found in the LICENSE file.
 
 class I<T> {}
+
 mixin M1<T> on I<T> {}
 
 //////////////////////////////////////////////////////
@@ -10,6 +11,9 @@ mixin M1<T> on I<T> {}
 // the "on" clause of a mixin
 ///////////////////////////////////////////////////////
 
-mixin A00Mixin on I<int>, M1 {} /*@compile-error=unspecified*/
+mixin A00Mixin on I<int>, M1 {}
+//    ^^^^^^^^
+// [analyzer] COMPILE_TIME_ERROR.CONFLICTING_GENERIC_INTERFACES
+// [cfe] 'I with M1' can't implement both 'I<int>' and 'I<dynamic>'
 
-void main() {}
\ No newline at end of file
+void main() {}
diff --git a/tests/language/mixin_legacy/with_two_implicit_constructors_test.dart b/tests/language/mixin_legacy/with_two_implicit_constructors_test.dart
index cf872a2a514..bc21f21630c 100644
--- a/tests/language/mixin_legacy/with_two_implicit_constructors_test.dart
+++ b/tests/language/mixin_legacy/with_two_implicit_constructors_test.dart
@@ -18,5 +18,8 @@ class B extends A with Mixin {}
 
 main() {
   Expect.equals(2, new B().field);
-  new B.bar(); /*@compile-error=unspecified*/
+  new B.bar();
+  //    ^^^
+  // [analyzer] COMPILE_TIME_ERROR.NEW_WITH_UNDEFINED_CONSTRUCTOR
+  // [cfe] Couldn't find constructor 'B.bar'.
 }
diff --git a/tests/language_2/loop/for_in3_test.dart b/tests/language_2/loop/for_in3_test.dart
index 3f38724a335..f64bcc06aa4 100644
--- a/tests/language_2/loop/for_in3_test.dart
+++ b/tests/language_2/loop/for_in3_test.dart
@@ -8,5 +8,8 @@
 
 main() {
   var chars = [];
-  for (var c in "foo") chars.add(c); /*@compile-error=unspecified*/
+  for (var c in "foo") chars.add(c);
+  //            ^^^^^
+  // [analyzer] COMPILE_TIME_ERROR.FOR_IN_OF_INVALID_TYPE
+  // [cfe] The type 'String' used in the 'for' loop must implement 'Iterable<dynamic>'.
 }
diff --git a/tests/language_2/main/not_a_function_test.dart b/tests/language_2/main/not_a_function_test.dart
index ff2b02a32cf..5b5321c59fe 100644
--- a/tests/language_2/main/not_a_function_test.dart
+++ b/tests/language_2/main/not_a_function_test.dart
@@ -6,4 +6,7 @@
 
 main() {}
 
-var main; /*@compile-error=unspecified*/
+var main;
+//  ^^^^
+// [analyzer] COMPILE_TIME_ERROR.DUPLICATE_DEFINITION
+// [cfe] 'main' is already declared in this scope.
diff --git a/tests/language_2/malbounded/type_cast2_test.dart b/tests/language_2/malbounded/type_cast2_test.dart
index e001c815cb2..70d11c2d241 100644
--- a/tests/language_2/malbounded/type_cast2_test.dart
+++ b/tests/language_2/malbounded/type_cast2_test.dart
@@ -10,7 +10,11 @@ class A<T extends num> {}
 
 class B<T> {
   test() {
-    new A() as A<T>; /*@compile-error=unspecified*/
+    new A() as A<T>;
+    //         ^
+    // [cfe] Type argument 'T' doesn't conform to the bound 'num' of the type variable 'T' on 'A'.
+    //           ^
+    // [analyzer] COMPILE_TIME_ERROR.TYPE_ARGUMENT_NOT_MATCHING_BOUNDS
   }
 }
 
diff --git a/tests/language_2/malformed/type_test.dart b/tests/language_2/malformed/type_test.dart
index c68374ce3cf..f86205ab9be 100644
--- a/tests/language_2/malformed/type_test.dart
+++ b/tests/language_2/malformed/type_test.dart
@@ -5,7 +5,11 @@
 // @dart = 2.9
 
 null_() => null;
-final Undeclared/*@compile-error=unspecified*/ x = null_();
+final Undeclared x = null_();
+//    ^^^^^^^^^^
+// [analyzer] COMPILE_TIME_ERROR.UNDEFINED_CLASS
+// [cfe] 'Undeclared' isn't a type.
+// [cfe] Type 'Undeclared' not found.
 
 main() {
   print(x);
diff --git a/tests/language_2/mixin/with_two_implicit_constructors_test.dart b/tests/language_2/mixin/with_two_implicit_constructors_test.dart
index 99ec9256deb..a772cb27159 100644
--- a/tests/language_2/mixin/with_two_implicit_constructors_test.dart
+++ b/tests/language_2/mixin/with_two_implicit_constructors_test.dart
@@ -18,5 +18,8 @@ class B extends A with Mixin {}
 
 main() {
   Expect.equals(2, new B().field);
-  new B.bar(); /*@compile-error=unspecified*/
+  new B.bar();
+  //    ^^^
+  // [analyzer] COMPILE_TIME_ERROR.NEW_WITH_UNDEFINED_CONSTRUCTOR
+  // [cfe] Couldn't find constructor 'B.bar'.
 }
diff --git a/tests/language_2/mixin_declaration/mixin_declaration_inference_invalid_00_test.dart b/tests/language_2/mixin_declaration/mixin_declaration_inference_invalid_00_test.dart
index c9c7c6b657f..2ca0bcae55a 100644
--- a/tests/language_2/mixin_declaration/mixin_declaration_inference_invalid_00_test.dart
+++ b/tests/language_2/mixin_declaration/mixin_declaration_inference_invalid_00_test.dart
@@ -13,6 +13,11 @@ mixin M0<T> on I<T> {}
 ///////////////////////////////////////////////////////
 
 // Error since class hierarchy is inconsistent
-class A00 extends I with M0<int> {} /*@compile-error=unspecified*/
+class A00 extends I with M0<int> {}
+//    ^
+// [cfe] 'I with M0' can't implement both 'I<dynamic>' and 'I<int>'
+// [cfe] 'I<dynamic>' doesn't implement 'I<int>' so it can't be used with 'M0<int>'.
+//                       ^^
+// [analyzer] COMPILE_TIME_ERROR.MIXIN_APPLICATION_NOT_IMPLEMENTED_INTERFACE
 
 void main() {}
diff --git a/tests/language_2/mixin_declaration/mixin_declaration_inference_invalid_01_test.dart b/tests/language_2/mixin_declaration/mixin_declaration_inference_invalid_01_test.dart
index 5d6479f1e6e..794744cb6b8 100644
--- a/tests/language_2/mixin_declaration/mixin_declaration_inference_invalid_01_test.dart
+++ b/tests/language_2/mixin_declaration/mixin_declaration_inference_invalid_01_test.dart
@@ -15,6 +15,11 @@ mixin M1<T> on I<T> {}
 ///////////////////////////////////////////////////////
 
 // Error since class hierarchy is inconsistent
-class A00 extends I with M0, M1<int> {} /*@compile-error=unspecified*/
+class A00 extends I with M0, M1<int> {}
+//    ^
+// [cfe] 'I with M0, M1' can't implement both 'I<dynamic>' and 'I<int>'
+// [cfe] '_A00&I&M0' doesn't implement 'I<int>' so it can't be used with 'M1<int>'.
+//                           ^^
+// [analyzer] COMPILE_TIME_ERROR.MIXIN_APPLICATION_NOT_IMPLEMENTED_INTERFACE
 
 void main() {}
diff --git a/tests/language_2/mixin_declaration/mixin_declaration_inference_invalid_02_test.dart b/tests/language_2/mixin_declaration/mixin_declaration_inference_invalid_02_test.dart
index db71dbd64f2..5a91874d8a8 100644
--- a/tests/language_2/mixin_declaration/mixin_declaration_inference_invalid_02_test.dart
+++ b/tests/language_2/mixin_declaration/mixin_declaration_inference_invalid_02_test.dart
@@ -15,6 +15,11 @@ mixin M1<T> on I<T> {}
 ///////////////////////////////////////////////////////
 
 // Error since class hierarchy is inconsistent
-class A00 with M0, M1<int> {} /*@compile-error=unspecified*/
+class A00 with M0, M1<int> {}
+//    ^
+// [cfe] 'Object with M0, M1' can't implement both 'I<dynamic>' and 'I<int>'
+// [cfe] '_A00&Object&M0' doesn't implement 'I<int>' so it can't be used with 'M1<int>'.
+//                 ^^
+// [analyzer] COMPILE_TIME_ERROR.MIXIN_APPLICATION_NOT_IMPLEMENTED_INTERFACE
 
 void main() {}
diff --git a/tests/language_2/mixin_declaration/mixin_declaration_inference_invalid_03_test.dart b/tests/language_2/mixin_declaration/mixin_declaration_inference_invalid_03_test.dart
index cd7b086868b..3da5db19348 100644
--- a/tests/language_2/mixin_declaration/mixin_declaration_inference_invalid_03_test.dart
+++ b/tests/language_2/mixin_declaration/mixin_declaration_inference_invalid_03_test.dart
@@ -13,6 +13,9 @@ mixin M0<T> implements I<T> {}
 ///////////////////////////////////////////////////////
 
 // Error since class hierarchy is inconsistent
-class A00 extends Object with M0 implements I<int> {} /*@compile-error=unspecified*/
+class A00 extends Object with M0 implements I<int> {}
+//    ^^^
+// [analyzer] COMPILE_TIME_ERROR.CONFLICTING_GENERIC_INTERFACES
+// [cfe] 'A00' can't implement both 'I<dynamic>' and 'I<int>'
 
 void main() {}
diff --git a/tests/language_2/mixin_declaration/mixin_declaration_inference_invalid_04_test.dart b/tests/language_2/mixin_declaration/mixin_declaration_inference_invalid_04_test.dart
index 55e952384fe..8b83d4a479c 100644
--- a/tests/language_2/mixin_declaration/mixin_declaration_inference_invalid_04_test.dart
+++ b/tests/language_2/mixin_declaration/mixin_declaration_inference_invalid_04_test.dart
@@ -13,6 +13,9 @@ mixin M0<T> implements I<T> {}
 ///////////////////////////////////////////////////////
 
 // Error since class hierarchy is inconsistent
-class A00 with M0 implements I<int> {} /*@compile-error=unspecified*/
+class A00 with M0 implements I<int> {}
+//    ^^^
+// [analyzer] COMPILE_TIME_ERROR.CONFLICTING_GENERIC_INTERFACES
+// [cfe] 'A00' can't implement both 'I<dynamic>' and 'I<int>'
 
 void main() {}
diff --git a/tests/language_2/mixin_declaration/mixin_declaration_inference_invalid_05_test.dart b/tests/language_2/mixin_declaration/mixin_declaration_inference_invalid_05_test.dart
index e41b8f7e26e..9e6ca94f790 100644
--- a/tests/language_2/mixin_declaration/mixin_declaration_inference_invalid_05_test.dart
+++ b/tests/language_2/mixin_declaration/mixin_declaration_inference_invalid_05_test.dart
@@ -15,6 +15,9 @@ mixin M1<T> implements I<T> {}
 ///////////////////////////////////////////////////////
 
 // Error since class hierarchy is inconsistent
-class A00 extends I<int> with M0<int>, M1 {} /*@compile-error=unspecified*/
+class A00 extends I<int> with M0<int>, M1 {}
+//    ^^^
+// [analyzer] COMPILE_TIME_ERROR.CONFLICTING_GENERIC_INTERFACES
+// [cfe] 'I with M0, M1' can't implement both 'I<int>' and 'I<dynamic>'
 
 void main() {}
diff --git a/tests/language_2/mixin_declaration/mixin_declaration_inference_invalid_06_test.dart b/tests/language_2/mixin_declaration/mixin_declaration_inference_invalid_06_test.dart
index a3a2934eade..e1e18418a65 100644
--- a/tests/language_2/mixin_declaration/mixin_declaration_inference_invalid_06_test.dart
+++ b/tests/language_2/mixin_declaration/mixin_declaration_inference_invalid_06_test.dart
@@ -5,6 +5,7 @@
 // @dart = 2.9
 
 class I<X> {}
+
 class J<X> {}
 
 mixin M0<S, T> implements I<S>, J<T> {}
@@ -16,10 +17,21 @@ mixin M1<S, T> implements I<S>, J<T> {}
 ///////////////////////////////////////////////////////
 
 class A00 extends I<int> with M0 {}
+//    ^^^
+// [analyzer] COMPILE_TIME_ERROR.CONFLICTING_GENERIC_INTERFACES
+// [cfe] 'I with M0' can't implement both 'I<int>' and 'I<dynamic>'
 
 class A01 extends J<int> with M1 {}
+//    ^^^
+// [analyzer] COMPILE_TIME_ERROR.CONFLICTING_GENERIC_INTERFACES
+// [cfe] 'J with M1' can't implement both 'J<int>' and 'J<dynamic>'
 
 // Error since class hierarchy is inconsistent
-class A02 extends A00 implements A01 {} /*@compile-error=unspecified*/
+class A02 extends A00 implements A01 {}
+//    ^^^
+// [analyzer] COMPILE_TIME_ERROR.CONFLICTING_GENERIC_INTERFACES
+// [analyzer] COMPILE_TIME_ERROR.CONFLICTING_GENERIC_INTERFACES
+// [cfe] 'A02' can't implement both 'I<int>' and 'I<dynamic>'
+// [cfe] 'A02' can't implement both 'J<dynamic>' and 'J<int>'
 
 void main() {}
diff --git a/tests/language_2/mixin_declaration/mixin_declaration_inference_invalid_07_test.dart b/tests/language_2/mixin_declaration/mixin_declaration_inference_invalid_07_test.dart
index 956f20d35fa..fadea9d8d3f 100644
--- a/tests/language_2/mixin_declaration/mixin_declaration_inference_invalid_07_test.dart
+++ b/tests/language_2/mixin_declaration/mixin_declaration_inference_invalid_07_test.dart
@@ -16,6 +16,9 @@ class M1 implements I<int> {}
 
 // M0 is inferred as M0<int, Comparable<dynamic>>
 // Error since super-bounded type not allowed
-class A extends M1 with M0 {} /*@compile-error=unspecified*/
+class A extends M1 with M0 {}
+//                      ^^
+// [analyzer] COMPILE_TIME_ERROR.TYPE_ARGUMENT_NOT_MATCHING_BOUNDS
+// [cfe] Inferred type argument 'Comparable<dynamic>' doesn't conform to the bound 'Comparable<Y>' of the type variable 'Y' on 'M0'.
 
 void main() {}
diff --git a/tests/language_2/mixin_declaration/mixin_declaration_inference_invalid_08_test.dart b/tests/language_2/mixin_declaration/mixin_declaration_inference_invalid_08_test.dart
index c49d34164ea..e6d98491721 100644
--- a/tests/language_2/mixin_declaration/mixin_declaration_inference_invalid_08_test.dart
+++ b/tests/language_2/mixin_declaration/mixin_declaration_inference_invalid_08_test.dart
@@ -14,10 +14,12 @@ mixin M1<T> implements I<String, T> {}
 // Inference is not bi-directional
 ///////////////////////////////////////////////////////
 
-
 // M0<String>, M1<int> is a solution, but we shouldn't find it
 // M0 inferred as M0<dynamic>
 // M1 inferred as M1<dynamic>
-class A with M0, M1 {} /*@compile-error=unspecified*/
+class A with M0, M1 {}
+//    ^
+// [analyzer] COMPILE_TIME_ERROR.CONFLICTING_GENERIC_INTERFACES
+// [cfe] 'Object with M0, M1' can't implement both 'I<dynamic, int>' and 'I<String, dynamic>'
 
 void main() {}
diff --git a/tests/language_2/mixin_declaration/mixin_declaration_inference_invalid_09_test.dart b/tests/language_2/mixin_declaration/mixin_declaration_inference_invalid_09_test.dart
index 245644009a1..e589fb7e08b 100644
--- a/tests/language_2/mixin_declaration/mixin_declaration_inference_invalid_09_test.dart
+++ b/tests/language_2/mixin_declaration/mixin_declaration_inference_invalid_09_test.dart
@@ -20,6 +20,9 @@ mixin M1<T> implements I<List<T>, T> {}
 // U0 = List<U1>
 // U1 = List<U0>
 // which has no finite solution
-class A with M0, M1 {} /*@compile-error=unspecified*/
+class A with M0, M1 {}
+//    ^
+// [analyzer] COMPILE_TIME_ERROR.CONFLICTING_GENERIC_INTERFACES
+// [cfe] 'Object with M0, M1' can't implement both 'I<dynamic, List<dynamic>>' and 'I<List<dynamic>, dynamic>'
 
 void main() {}
diff --git a/tests/language_2/mixin_declaration/mixin_declaration_inference_invalid_10_test.dart b/tests/language_2/mixin_declaration/mixin_declaration_inference_invalid_10_test.dart
index d76c854a95d..9dc67535391 100644
--- a/tests/language_2/mixin_declaration/mixin_declaration_inference_invalid_10_test.dart
+++ b/tests/language_2/mixin_declaration/mixin_declaration_inference_invalid_10_test.dart
@@ -5,13 +5,20 @@
 // @dart = 2.9
 
 class I<T> {}
+
 class J<T> {}
+
 mixin M0<T> implements I<T>, J<T> {}
 
 //////////////////////////////////////////////////////
 // Over-constrained results are caught
 ///////////////////////////////////////////////////////
 
-class A with I<int>, J<double>, M0 {} /*@compile-error=unspecified*/
+class A with I<int>, J<double>, M0 {}
+//    ^
+// [analyzer] COMPILE_TIME_ERROR.CONFLICTING_GENERIC_INTERFACES
+// [analyzer] COMPILE_TIME_ERROR.CONFLICTING_GENERIC_INTERFACES
+// [cfe] 'Object with I, J, M0' can't implement both 'I<int>' and 'I<dynamic>'
+// [cfe] 'Object with I, J, M0' can't implement both 'J<double>' and 'J<dynamic>'
 
 void main() {}
diff --git a/tests/language_2/mixin_declaration/mixin_declaration_inference_invalid_11_test.dart b/tests/language_2/mixin_declaration/mixin_declaration_inference_invalid_11_test.dart
index eca6a978730..90d66d35808 100644
--- a/tests/language_2/mixin_declaration/mixin_declaration_inference_invalid_11_test.dart
+++ b/tests/language_2/mixin_declaration/mixin_declaration_inference_invalid_11_test.dart
@@ -5,6 +5,7 @@
 // @dart = 2.9
 
 class I<T> {}
+
 mixin M1<T> on I<T> {}
 
 //////////////////////////////////////////////////////
@@ -12,6 +13,9 @@ mixin M1<T> on I<T> {}
 // the "on" clause of a mixin
 ///////////////////////////////////////////////////////
 
-mixin A00Mixin on I<int>, M1 {} /*@compile-error=unspecified*/
+mixin A00Mixin on I<int>, M1 {}
+//    ^^^^^^^^
+// [analyzer] COMPILE_TIME_ERROR.CONFLICTING_GENERIC_INTERFACES
+// [cfe] 'I with M1' can't implement both 'I<int>' and 'I<dynamic>'
 
 void main() {}