Fix 'this' parameter handling in getUnionSignatures

zfkl · Dec 20, 2017 · c78a6a5 · c78a6a5
1 parent 8173733
commit c78a6a5
Showing 1 changed file with 1 addition and 1 deletion.
diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
@@ -5936,7 +5936,7 @@ namespace ts {
                             if (unionSignatures.length > 1) {
                                 let thisParameter = signature.thisParameter;
                                 if (forEach(unionSignatures, sig => sig.thisParameter)) {
-                                    const thisType = getUnionType(map(unionSignatures, sig => getTypeOfSymbol(sig.thisParameter) || anyType), UnionReduction.Subtype);
+                                    const thisType = getUnionType(map(unionSignatures, sig => sig.thisParameter ? getTypeOfSymbol(sig.thisParameter) : anyType), UnionReduction.Subtype);
                                     thisParameter = createSymbolWithType(signature.thisParameter, thisType);
                                 }
                                 s = cloneSignature(signature);