Remove null and undefined from contextual 'this' type

ahejlsberg · ahejlsberg · commit fa02c808d1f3 · 2017-03-07T09:07:34.000-08:00
diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
@@ -11601,7 +11601,7 @@ namespace ts {
                     }
                 }
             }
-            if (compilerOptions.noImplicitThis) {
+            if (noImplicitThis) {
                 const containingLiteral = getContainingObjectLiteral(func);
                 if (containingLiteral) {
                     // We have an object literal method. Check if the containing object literal has a contextual type
@@ -11622,9 +11622,9 @@ namespace ts {
                         type = getApparentTypeOfContextualType(literal);
                     }
                     // There was no contextual ThisType<T> for the containing object literal, so the contextual type
-                    // for 'this' is the contextual type for the containing object literal or the type of the object
-                    // literal itself.
-                    return contextualType || checkExpressionCached(containingLiteral);
+                    // for 'this' is the non-null form of the contextual type for the containing object literal or
+                    // the type of the object literal itself.
+                    return contextualType ? getNonNullableType(contextualType) : checkExpressionCached(containingLiteral);
                 }
                 // In an assignment of the form 'obj.xxx = function(...)' or 'obj[xxx] = function(...)', the
                 // contextual type for 'this' is 'obj'.

Original file line number	Diff line number	Diff line change
`@@ -11601,7 +11601,7 @@ namespace ts {`
`11601`	`11601`	`}`
`11602`	`11602`	`}`
`11603`	`11603`	`}`
`11604`		`- if (compilerOptions.noImplicitThis) {`
	`11604`	`+ if (noImplicitThis) {`
`11605`	`11605`	`const containingLiteral = getContainingObjectLiteral(func);`
`11606`	`11606`	`if (containingLiteral) {`
`11607`	`11607`	`// We have an object literal method. Check if the containing object literal has a contextual type`
`@@ -11622,9 +11622,9 @@ namespace ts {`
`11622`	`11622`	`type = getApparentTypeOfContextualType(literal);`
`11623`	`11623`	`}`
`11624`	`11624`	`// There was no contextual ThisType<T> for the containing object literal, so the contextual type`
`11625`		`- // for 'this' is the contextual type for the containing object literal or the type of the object`
`11626`		`- // literal itself.`
`11627`		`- return contextualType \|\| checkExpressionCached(containingLiteral);`
	`11625`	`+ // for 'this' is the non-null form of the contextual type for the containing object literal or`
	`11626`	`+ // the type of the object literal itself.`
	`11627`	`+ return contextualType ? getNonNullableType(contextualType) : checkExpressionCached(containingLiteral);`
`11628`	`11628`	`}`
`11629`	`11629`	`// In an assignment of the form 'obj.xxx = function(...)' or 'obj[xxx] = function(...)', the`
`11630`	`11630`	`// contextual type for 'this' is 'obj'.`