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Add additional error checking

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This commit is contained in:
Anders Hejlsberg 2016-05-17 13:45:40 -07:00
parent e028c0fd3d
commit 88d7f23f10
2 changed files with 9 additions and 2 deletions
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7
src/compiler/checker.ts
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@ -11684,7 +11684,10 @@ namespace ts {
const hasExplicitReturn = func.flags & NodeFlags.HasExplicitReturn;
if (returnType && !hasExplicitReturn) {
if (returnType === neverType) {
error(func.type, Diagnostics.A_function_returning_never_cannot_have_a_reachable_end_point);
}
else if (returnType && !hasExplicitReturn) {
// minimal check: function has syntactic return type annotation and no explicit return statements in the body
// this function does not conform to the specification.
// NOTE: having returnType !== undefined is a precondition for entering this branch so func.type will always be present
@ -14821,7 +14824,7 @@ namespace ts {
if (func) {
const signature = getSignatureFromDeclaration(func);
const returnType = getReturnTypeOfSignature(signature);
if (strictNullChecks || node.expression) {
if (strictNullChecks || node.expression || returnType === neverType) {
const exprType = node.expression ? checkExpressionCached(node.expression) : undefinedType;
if (func.asteriskToken) {

4
src/compiler/diagnosticMessages.json
View file

@ -1751,6 +1751,10 @@
"category": "Error",
"code": 2533
},
"A function returning 'never' cannot have a reachable end point.": {
"category": "Error",
"code": 2534
},
"JSX element attributes type '{0}' may not be a union type.": {
"category": "Error",
"code": 2600