Fix subtype relationship for 'never' type

ahejlsberg · ahejlsberg · commit 99fd6dcb3e96 · 2016-05-21T11:17:30.000-07:00
diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
@@ -5859,7 +5859,7 @@ namespace ts {
                 }
 
                 if (!(target.flags & TypeFlags.Never)) {
-                    if (target.flags & TypeFlags.Any) return Ternary.True;
+                    if (target.flags & TypeFlags.Any || source.flags & TypeFlags.Never) return Ternary.True;
                     if (source.flags & TypeFlags.Undefined) {
                         if (!strictNullChecks || target.flags & (TypeFlags.Undefined | TypeFlags.Void) || source === emptyArrayElementType) return Ternary.True;
                     }
@@ -5874,7 +5874,7 @@ namespace ts {
                     }
                     if (source.flags & TypeFlags.StringLiteral && target === stringType) return Ternary.True;
                     if (relation === assignableRelation || relation === comparableRelation) {
-                        if (source.flags & (TypeFlags.Any | TypeFlags.Never)) return Ternary.True;
+                        if (source.flags & TypeFlags.Any) return Ternary.True;
                         if (source === numberType && target.flags & TypeFlags.Enum) return Ternary.True;
                     }
                     if (source.flags & TypeFlags.Boolean && target.flags & TypeFlags.Boolean) {

Original file line number	Diff line number	Diff line change
`@@ -5859,7 +5859,7 @@ namespace ts {`
`5859`	`5859`	`}`
`5860`	`5860`
`5861`	`5861`	`if (!(target.flags & TypeFlags.Never)) {`
`5862`		`- if (target.flags & TypeFlags.Any) return Ternary.True;`
	`5862`	`+ if (target.flags & TypeFlags.Any \|\| source.flags & TypeFlags.Never) return Ternary.True;`
`5863`	`5863`	`if (source.flags & TypeFlags.Undefined) {`
`5864`	`5864`	`if (!strictNullChecks \|\| target.flags & (TypeFlags.Undefined \| TypeFlags.Void) \|\| source === emptyArrayElementType) return Ternary.True;`
`5865`	`5865`	`}`
`@@ -5874,7 +5874,7 @@ namespace ts {`
`5874`	`5874`	`}`
`5875`	`5875`	`if (source.flags & TypeFlags.StringLiteral && target === stringType) return Ternary.True;`
`5876`	`5876`	`if (relation === assignableRelation \|\| relation === comparableRelation) {`
`5877`		`- if (source.flags & (TypeFlags.Any \| TypeFlags.Never)) return Ternary.True;`
	`5877`	`+ if (source.flags & TypeFlags.Any) return Ternary.True;`
`5878`	`5878`	`if (source === numberType && target.flags & TypeFlags.Enum) return Ternary.True;`
`5879`	`5879`	`}`
`5880`	`5880`	`if (source.flags & TypeFlags.Boolean && target.flags & TypeFlags.Boolean) {`