microsoft · ahejlsberg · Sep 6, 2014 · Sep 6, 2014
diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
@@ -4330,8 +4330,8 @@ module ts {
             var targetType = getTypeFromTypeNode(node.type);
             if (fullTypeCheck && targetType !== unknownType) {
                 var widenedType = getWidenedType(exprType);
-                if (!(isTypeAssignableTo(exprType, targetType) || isTypeAssignableTo(targetType, widenedType))) {
-                    checkTypeAssignableTo(targetType, widenedType, node, Diagnostics.Neither_type_0_nor_type_1_is_assignable_to_the_other_Colon, Diagnostics.Neither_type_0_nor_type_1_is_assignable_to_the_other);
+                if (!(isTypeAssignableTo(targetType, widenedType))) {
+                    checkTypeAssignableTo(exprType, targetType, node, Diagnostics.Neither_type_0_nor_type_1_is_assignable_to_the_other_Colon, Diagnostics.Neither_type_0_nor_type_1_is_assignable_to_the_other);
                 }
             }
             return targetType;

diff --git a/tests/baselines/reference/arrayCast.errors.txt b/tests/baselines/reference/arrayCast.errors.txt
@@ -3,8 +3,9 @@
     // has type { foo: string }[], which is not assignable to { id: number }[].
     <{ id: number; }[]>[{ foo: "s" }];
     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-!!! Neither type '{ id: number; }[]' nor type '{ foo: string; }[]' is assignable to the other:
-!!!   Type '{ id: number; }' is not assignable to type '{ foo: string; }'.
+!!! Neither type '{ foo: string; }[]' nor type '{ id: number; }[]' is assignable to the other:
+!!!   Type '{ foo: string; }' is not assignable to type '{ id: number; }':
+!!!     Property 'id' is missing in type '{ foo: string; }'.
 
     // Should succeed, as the {} element causes the type of the array to be {}[]
     <{ id: number; }[]>[{ foo: "s" }, {}]; 
diff --git a/tests/baselines/reference/contextualTyping39.errors.txt b/tests/baselines/reference/contextualTyping39.errors.txt
@@ -1,4 +1,5 @@
 ==== tests/cases/compiler/contextualTyping39.ts (1 errors) ====
     var foo = <{ (): number; }> function() { return "err"; };
               ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-!!! Neither type '() => number' nor type '() => string' is assignable to the other.
+!!! Neither type '() => string' nor type '() => number' is assignable to the other:
+!!!   Type 'string' is not assignable to type 'number'.
diff --git a/tests/baselines/reference/contextualTyping41.errors.txt b/tests/baselines/reference/contextualTyping41.errors.txt
@@ -1,4 +1,5 @@
 ==== tests/cases/compiler/contextualTyping41.ts (1 errors) ====
     var foo = <{():number; (i:number):number; }> (function(){return "err";});
               ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-!!! Neither type '{ (): number; (i: number): number; }' nor type '() => string' is assignable to the other.
+!!! Neither type '() => string' nor type '{ (): number; (i: number): number; }' is assignable to the other:
+!!!   Type 'string' is not assignable to type 'number'.
diff --git a/tests/baselines/reference/defaultArgsInFunctionExpressions.errors.txt b/tests/baselines/reference/defaultArgsInFunctionExpressions.errors.txt
@@ -22,7 +22,7 @@
     // Contextually type the default arg with the type annotation
     var f3 = function (a: (s: string) => any = (s) => <number>s) { };
                                                       ~~~~~~~~~
-!!! Neither type 'number' nor type 'string' is assignable to the other.
+!!! Neither type 'string' nor type 'number' is assignable to the other.
 
     // Type check using the function's contextual type
     var f4: (a: number) => void = function (a = "") { };
@@ -32,7 +32,7 @@
     // Contextually type the default arg using the function's contextual type
     var f5: (a: (s: string) => any) => void = function (a = s => <number>s) { };
                                                                  ~~~~~~~~~
-!!! Neither type 'number' nor type 'string' is assignable to the other.
+!!! Neither type 'string' nor type 'number' is assignable to the other.
 
     // Instantiated module
     module T { }

diff --git a/tests/baselines/reference/fuzzy.errors.txt b/tests/baselines/reference/fuzzy.errors.txt
@@ -32,7 +32,8 @@
             worksToo():R {
                 return <R>({ oneI: this });
                        ~~~~~~~~~~~~~~~~~~~
-!!! Neither type 'R' nor type '{ oneI: C; }' is assignable to the other.
+!!! Neither type '{ oneI: C; }' nor type 'R' is assignable to the other:
+!!!   Property 'anything' is missing in type '{ oneI: C; }'.
             }
         }
     }

diff --git a/tests/baselines/reference/genericTypeAssertions1.errors.txt b/tests/baselines/reference/genericTypeAssertions1.errors.txt
@@ -10,5 +10,6 @@
 !!! Type 'A<A<number>>' is not assignable to type 'A<number>':
 !!!   Type 'A<number>' is not assignable to type 'number'.
                         ~~~~~~~~~~~~~~~~~
-!!! Neither type 'A<A<number>>' nor type 'A<number>' is assignable to the other:
-!!!   Type 'A<number>' is not assignable to type 'number'.
+!!! Neither type 'A<number>' nor type 'A<A<number>>' is assignable to the other:
+!!!   Type 'number' is not assignable to type 'A<number>':
+!!!     Property 'foo' is missing in type 'Number'.
diff --git a/tests/baselines/reference/genericTypeAssertions2.errors.txt b/tests/baselines/reference/genericTypeAssertions2.errors.txt
@@ -22,4 +22,5 @@
     var r4: A<number> = <A<number>>new A();
     var r5: A<number> = <A<number>>[]; // error
                         ~~~~~~~~~~~~~
-!!! Neither type 'A<number>' nor type 'any[]' is assignable to the other.
+!!! Neither type 'undefined[]' nor type 'A<number>' is assignable to the other:
+!!!   Property 'foo' is missing in type 'undefined[]'.
diff --git a/tests/baselines/reference/genericTypeAssertions4.errors.txt b/tests/baselines/reference/genericTypeAssertions4.errors.txt
@@ -29,8 +29,8 @@
         y = <T>a;
         y = <T>b; // error: cannot convert B to T
             ~~~~
-!!! Neither type 'T' nor type 'B' is assignable to the other.
+!!! Neither type 'B' nor type 'T' is assignable to the other.
         y = <T>c; // error: cannot convert C to T
             ~~~~
-!!! Neither type 'T' nor type 'C' is assignable to the other.
+!!! Neither type 'C' nor type 'T' is assignable to the other.
     }
diff --git a/tests/baselines/reference/genericTypeAssertions5.errors.txt b/tests/baselines/reference/genericTypeAssertions5.errors.txt
@@ -29,8 +29,8 @@
         y = <T>a;
         y = <T>b; // error: cannot convert B to T
             ~~~~
-!!! Neither type 'T' nor type 'B' is assignable to the other.
+!!! Neither type 'B' nor type 'T' is assignable to the other.
         y = <T>c; // error: cannot convert C to T
             ~~~~
-!!! Neither type 'T' nor type 'C' is assignable to the other.
+!!! Neither type 'C' nor type 'T' is assignable to the other.
     }
diff --git a/tests/baselines/reference/genericTypeAssertions6.errors.txt b/tests/baselines/reference/genericTypeAssertions6.errors.txt
@@ -8,10 +8,10 @@
         f(x: T, y: U) {
             x = <T>y;
                 ~~~~
-!!! Neither type 'T' nor type 'U' is assignable to the other.
+!!! Neither type 'U' nor type 'T' is assignable to the other.
             y = <U>x;
                 ~~~~
-!!! Neither type 'U' nor type 'T' is assignable to the other.
+!!! Neither type 'T' nor type 'U' is assignable to the other.
         }
     }
 
@@ -23,7 +23,7 @@
             var d = <U>new Date();
             var e = <T><U>new Date();
                     ~~~~~~~~~~~~~~~~
-!!! Neither type 'T' nor type 'U' is assignable to the other.
+!!! Neither type 'U' nor type 'T' is assignable to the other.
         }
     }
 

diff --git a/tests/baselines/reference/intTypeCheck.errors.txt b/tests/baselines/reference/intTypeCheck.errors.txt
@@ -315,7 +315,7 @@
     var obj69: i7 = new obj66;
     var obj70: i7 = <i7>new Base;
                     ~~~~~~~~~~~~
-!!! Neither type 'i7' nor type 'Base' is assignable to the other.
+!!! Neither type 'Base' nor type 'i7' is assignable to the other.
     var obj71: i7 = null;
     var obj72: i7 = function () { };
         ~~~~~

diff --git a/tests/baselines/reference/literals-negative.errors.txt b/tests/baselines/reference/literals-negative.errors.txt
@@ -5,7 +5,7 @@
     var s = <string>(null);
     var b = <boolean>(n);
             ~~~~~~~~~~~~
-!!! Neither type 'boolean' nor type 'number' is assignable to the other.
+!!! Neither type 'number' nor type 'boolean' is assignable to the other.
 
     function isVoid() : void { }
 

diff --git a/tests/baselines/reference/typeAssertions.errors.txt b/tests/baselines/reference/typeAssertions.errors.txt
@@ -33,20 +33,22 @@
     someBase = <SomeBase>someBase;
     someBase = <SomeBase>someOther; // Error
                ~~~~~~~~~~~~~~~~~~~
-!!! Neither type 'SomeBase' nor type 'SomeOther' is assignable to the other.
+!!! Neither type 'SomeOther' nor type 'SomeBase' is assignable to the other:
+!!!   Property 'p' is missing in type 'SomeOther'.
 
     someDerived = <SomeDerived>someDerived;
     someDerived = <SomeDerived>someBase;
     someDerived = <SomeDerived>someOther; // Error
                   ~~~~~~~~~~~~~~~~~~~~~~
-!!! Neither type 'SomeDerived' nor type 'SomeOther' is assignable to the other.
+!!! Neither type 'SomeOther' nor type 'SomeDerived' is assignable to the other:
+!!!   Property 'x' is missing in type 'SomeOther'.
 
     someOther = <SomeOther>someDerived; // Error
                 ~~~~~~~~~~~~~~~~~~~~~~
-!!! Neither type 'SomeOther' nor type 'SomeDerived' is assignable to the other.
+!!! Neither type 'SomeDerived' nor type 'SomeOther' is assignable to the other.
     someOther = <SomeOther>someBase; // Error
                 ~~~~~~~~~~~~~~~~~~~
-!!! Neither type 'SomeOther' nor type 'SomeBase' is assignable to the other.
+!!! Neither type 'SomeBase' nor type 'SomeOther' is assignable to the other.
     someOther = <SomeOther>someOther;