assignContextualParameterTypes handles arguments object

sandersn · sandersn · commit 2fdb5b8659bb · 2017-09-11T11:16:01.000-07:00
Previously, it would crash &amp;mdash; the arguments object is a transient
symbol with no declaration, and `getEffectiveTypeAnnotationNode`
does not accept `undefined`.
diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
@@ -16665,8 +16665,9 @@ namespace ts {
                 }
             }
             if (signature.hasRestParameter && isRestParameterIndex(context, signature.parameters.length - 1)) {
+                // parameter might be a transient symbol generated by use of `arguments` in the function body.
                 const parameter = lastOrUndefined(signature.parameters);
-                if (!getEffectiveTypeAnnotationNode(<ParameterDeclaration>parameter.valueDeclaration)) {
+                if (isTransientSymbol(parameter) || !getEffectiveTypeAnnotationNode(<ParameterDeclaration>parameter.valueDeclaration)) {
                     const contextualParameterType = getTypeOfSymbol(lastOrUndefined(context.parameters));
                     assignTypeToParameterAndFixTypeParameters(parameter, contextualParameterType);
                 }

Original file line number	Diff line number	Diff line change
`@@ -16665,8 +16665,9 @@ namespace ts {`
`16665`	`16665`	`}`
`16666`	`16666`	`}`
`16667`	`16667`	`if (signature.hasRestParameter && isRestParameterIndex(context, signature.parameters.length - 1)) {`
	`16668`	+ // parameter might be a transient symbol generated by use of `arguments` in the function body.
`16668`	`16669`	`const parameter = lastOrUndefined(signature.parameters);`
`16669`		`- if (!getEffectiveTypeAnnotationNode(<ParameterDeclaration>parameter.valueDeclaration)) {`
	`16670`	`+ if (isTransientSymbol(parameter) \|\| !getEffectiveTypeAnnotationNode(<ParameterDeclaration>parameter.valueDeclaration)) {`
`16670`	`16671`	`const contextualParameterType = getTypeOfSymbol(lastOrUndefined(context.parameters));`
`16671`	`16672`	`assignTypeToParameterAndFixTypeParameters(parameter, contextualParameterType);`
`16672`	`16673`	`}`