Fix 'this' parameter handling in getUnionSignatures

ahejlsberg · ahejlsberg · commit c78a6a5cad6a · 2017-12-19T19:48:30.000-08:00
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);

Original file line number	Diff line number	Diff line change
`@@ -5936,7 +5936,7 @@ namespace ts {`
`5936`	`5936`	`if (unionSignatures.length > 1) {`
`5937`	`5937`	`let thisParameter = signature.thisParameter;`
`5938`	`5938`	`if (forEach(unionSignatures, sig => sig.thisParameter)) {`
`5939`		`- const thisType = getUnionType(map(unionSignatures, sig => getTypeOfSymbol(sig.thisParameter) \|\| anyType), UnionReduction.Subtype);`
	`5939`	`+ const thisType = getUnionType(map(unionSignatures, sig => sig.thisParameter ? getTypeOfSymbol(sig.thisParameter) : anyType), UnionReduction.Subtype);`
`5940`	`5940`	`thisParameter = createSymbolWithType(signature.thisParameter, thisType);`
`5941`	`5941`	`}`
`5942`	`5942`	`s = cloneSignature(signature);`