Prefer error candidates with no rest parameters over those with

ahejlsberg · ahejlsberg · commit 2e17debbfbf8 · 2018-09-12T13:16:33.000-07:00
diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
@@ -19453,7 +19453,10 @@ namespace ts {
                         checkCandidate = candidate;
                     }
                     if (!checkApplicableSignature(node, args, checkCandidate, relation, excludeArgument, /*reportErrors*/ false)) {
-                        candidateForArgumentError = checkCandidate;
+                        // Give preference to error candidates that have no rest parameters (as they are more specific)
+                        if (!candidateForArgumentError || getEffectiveRestType(candidateForArgumentError) || !getEffectiveRestType(checkCandidate)) {
+                            candidateForArgumentError = checkCandidate;
+                        }
                         continue;
                     }
                     if (excludeArgument) {
@@ -19466,7 +19469,10 @@ namespace ts {
                             checkCandidate = getSignatureInstantiation(candidate, typeArgumentTypes, isInJavaScriptFile(candidate.declaration));
                         }
                         if (!checkApplicableSignature(node, args, checkCandidate, relation, excludeArgument, /*reportErrors*/ false)) {
-                            candidateForArgumentError = checkCandidate;
+                            // Give preference to error candidates that have no rest parameters (as they are more specific)
+                            if (!candidateForArgumentError || getEffectiveRestType(candidateForArgumentError) || !getEffectiveRestType(checkCandidate)) {
+                                candidateForArgumentError = checkCandidate;
+                            }
                             continue;
                         }
                     }

Original file line number	Diff line number	Diff line change
`@@ -19453,7 +19453,10 @@ namespace ts {`
`19453`	`19453`	`checkCandidate = candidate;`
`19454`	`19454`	`}`
`19455`	`19455`	`if (!checkApplicableSignature(node, args, checkCandidate, relation, excludeArgument, /reportErrors/ false)) {`
`19456`		`- candidateForArgumentError = checkCandidate;`
	`19456`	`+ // Give preference to error candidates that have no rest parameters (as they are more specific)`
	`19457`	`+ if (!candidateForArgumentError \|\| getEffectiveRestType(candidateForArgumentError) \|\| !getEffectiveRestType(checkCandidate)) {`
	`19458`	`+ candidateForArgumentError = checkCandidate;`
	`19459`	`+ }`
`19457`	`19460`	`continue;`
`19458`	`19461`	`}`
`19459`	`19462`	`if (excludeArgument) {`
`@@ -19466,7 +19469,10 @@ namespace ts {`
`19466`	`19469`	`checkCandidate = getSignatureInstantiation(candidate, typeArgumentTypes, isInJavaScriptFile(candidate.declaration));`
`19467`	`19470`	`}`
`19468`	`19471`	`if (!checkApplicableSignature(node, args, checkCandidate, relation, excludeArgument, /reportErrors/ false)) {`
`19469`		`- candidateForArgumentError = checkCandidate;`
	`19472`	`+ // Give preference to error candidates that have no rest parameters (as they are more specific)`
	`19473`	`+ if (!candidateForArgumentError \|\| getEffectiveRestType(candidateForArgumentError) \|\| !getEffectiveRestType(checkCandidate)) {`
	`19474`	`+ candidateForArgumentError = checkCandidate;`
	`19475`	`+ }`
`19470`	`19476`	`continue;`
`19471`	`19477`	`}`
`19472`	`19478`	`}`