Add missing type relationship for conditional types

ahejlsberg · ahejlsberg · commit 8750bb8949ee · 2018-03-25T11:29:58.000-07:00
diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
@@ -10205,10 +10205,13 @@ namespace ts {
                             if (result = isRelatedTo(getTrueTypeFromConditionalType(<ConditionalType>source), getTrueTypeFromConditionalType(<ConditionalType>target), reportErrors)) {
                                 result &= isRelatedTo(getFalseTypeFromConditionalType(<ConditionalType>source), getFalseTypeFromConditionalType(<ConditionalType>target), reportErrors);
                             }
-                            if (result) {
-                                errorInfo = saveErrorInfo;
-                                return result;
-                            }
+                        }
+                        else {
+                            result = isRelatedTo(getDefaultConstraintOfConditionalType(<ConditionalType>source), getDefaultConstraintOfConditionalType(<ConditionalType>target), reportErrors);
+                        }
+                        if (result) {
+                            errorInfo = saveErrorInfo;
+                            return result;
                         }
                     }
                     else if (relation !== definitelyAssignableRelation) {

Original file line number	Diff line number	Diff line change
`@@ -10205,10 +10205,13 @@ namespace ts {`
`10205`	`10205`	`if (result = isRelatedTo(getTrueTypeFromConditionalType(<ConditionalType>source), getTrueTypeFromConditionalType(<ConditionalType>target), reportErrors)) {`
`10206`	`10206`	`result &= isRelatedTo(getFalseTypeFromConditionalType(<ConditionalType>source), getFalseTypeFromConditionalType(<ConditionalType>target), reportErrors);`
`10207`	`10207`	`}`
`10208`		`- if (result) {`
`10209`		`- errorInfo = saveErrorInfo;`
`10210`		`- return result;`
`10211`		`- }`
	`10208`	`+ }`
	`10209`	`+ else {`
	`10210`	`+ result = isRelatedTo(getDefaultConstraintOfConditionalType(<ConditionalType>source), getDefaultConstraintOfConditionalType(<ConditionalType>target), reportErrors);`
	`10211`	`+ }`
	`10212`	`+ if (result) {`
	`10213`	`+ errorInfo = saveErrorInfo;`
	`10214`	`+ return result;`
`10212`	`10215`	`}`
`10213`	`10216`	`}`
`10214`	`10217`	`else if (relation !== definitelyAssignableRelation) {`