gopls/internal/analysis/modernize: prevent conversion of variadic functions to slices.ContainsFunc

Exclude variadic functions from being converted to slices.ContainsFunc to avoid type errors.

Fixes golang/go#73269

Change-Id: I2259d6639515939717305ab75553393485aca8e8
Reviewed-on: https://go-review.googlesource.com/c/tools/+/663436
Reviewed-by: Robert Findley <[email protected]>
Auto-Submit: Alan Donovan <[email protected]>
Reviewed-by: Alan Donovan <[email protected]>
LUCI-TryBot-Result: Go LUCI <[email protected]>

Author: karamaru-alpha

gopls/internal/analysis/modernize/slicescontains.go

@@ -129,6 +129,11 @@ func slicescontains(pass *analysis.Pass) {
 				isSliceElem(cond.Args[0]) &&
 				typeutil.Callee(info, cond) != nil { // not a conversion
 
+				// skip variadic functions
+				if sig, ok := info.TypeOf(cond.Fun).(*types.Signature); ok && sig.Variadic() {
+					return
+				}
+
 				funcName = "ContainsFunc"
 				arg2 = cond.Fun // "if predicate(elem)"
 			}

gopls/internal/analysis/modernize/testdata/src/slicescontains/slicescontains.go

@@ -146,3 +146,26 @@ func nopeNeedleHaystackDifferentTypes2(x error, args []any) {
 		}
 	}
 }
+
+func nopeVariadicNamedContainsFunc(slice []int) bool {
+	for _, elem := range slice {
+		if variadicPredicate(elem) {
+			return true
+		}
+	}
+	return false
+}
+
+func variadicPredicate(int, ...any) bool
+
+func nopeVariadicContainsFunc(slice []int) bool {
+	f := func(int, ...any) bool {
+		return true
+	}
+	for _, elem := range slice {
+		if f(elem) {
+			return true
+		}
+	}
+	return false
+}

gopls/internal/analysis/modernize/testdata/src/slicescontains/slicescontains.go.golden

@@ -102,3 +102,26 @@ func nopeNeedleHaystackDifferentTypes2(x error, args []any) {
 		}
 	}
 }
+
+func nopeVariadicNamedContainsFunc(slice []int) bool {
+	for _, elem := range slice {
+		if variadicPredicate(elem) {
+			return true
+		}
+	}
+	return false
+}
+
+func variadicPredicate(int, ...any) bool
+
+func nopeVariadicContainsFunc(slice []int) bool {
+	f := func(int, ...any) bool {
+		return true
+	}
+	for _, elem := range slice {
+		if f(elem) {
+			return true
+		}
+	}
+	return false
+}