Fixed Testing

Author: Arthur Ozga

src/compiler/checker.ts

@@ -4763,26 +4763,32 @@ namespace ts {
  let targetSignatures = getSignaturesOfType(target, kind);
  let result = Ternary.True;
  let saveErrorInfo = errorInfo;
- 
+
  // Because the "abstractness" of a class is the same across all construct signatures
  // (internally we are checking the corresponding declaration), it is enough to perform 
  // the check and report an error once over all pairs of source and target construct signatures.
- let sourceErasedSignature = getErasedSignature(s);
- let targetErasedSignature = getErasedSignature(t);
+ let sourceSig = sourceSignatures[0];
+ // Note that in an extends-clause, targetSignatures is stripped, so the check never proceeds.
+ let targetSig = targetSignatures[0];
 
- let sourceReturnType = sourceErasedSignature && getReturnTypeOfSignature(sourceErasedSignature);
- let targetReturnType = targetErasedSignature && getReturnTypeOfSignature(targetErasedSignature);
+ if (sourceSig && targetSig) {
+ let sourceErasedSignature = getErasedSignature(sourceSig);
+ let targetErasedSignature = getErasedSignature(targetSig);
 
- let sourceReturnDecl = sourceReturnType && sourceReturnType.symbol && getDeclarationOfKind(sourceReturnType.symbol, SyntaxKind.ClassDeclaration);
- let targetReturnDecl = targetReturnType && targetReturnType.symbol && getDeclarationOfKind(targetReturnType.symbol, SyntaxKind.ClassDeclaration);
- let sourceIsAbstract = sourceReturnDecl && sourceReturnDecl.flags & NodeFlags.Abstract;
- let targetIsAbstract = targetReturnDecl && targetReturnDecl.flags & NodeFlags.Abstract;
+ let sourceReturnType = sourceErasedSignature && getReturnTypeOfSignature(sourceErasedSignature);
+ let targetReturnType = targetErasedSignature && getReturnTypeOfSignature(targetErasedSignature);
 
- if (sourceIsAbstract && !targetIsAbstract) {
- if (reportErrors) {
- reportError(Diagnostics.Cannot_assign_an_abstract_constructor_type_to_a_non_abstract_constructor_type);
+ let sourceReturnDecl = sourceReturnType && sourceReturnType.symbol && getDeclarationOfKind(sourceReturnType.symbol, SyntaxKind.ClassDeclaration);
+ let targetReturnDecl = targetReturnType && targetReturnType.symbol && getDeclarationOfKind(targetReturnType.symbol, SyntaxKind.ClassDeclaration);
+ let sourceIsAbstract = sourceReturnDecl && sourceReturnDecl.flags & NodeFlags.Abstract;
+ let targetIsAbstract = targetReturnDecl && targetReturnDecl.flags & NodeFlags.Abstract;
+
+ if (sourceIsAbstract && !targetIsAbstract) {
+ if (reportErrors) {
+ reportError(Diagnostics.Cannot_assign_an_abstract_constructor_type_to_a_non_abstract_constructor_type);
+ }
+ return Ternary.False;
  }
- result = Ternary.False;
  }
 
  outer: for (let t of targetSignatures) {