Document cases in type switch statement.

Don't print empty elements in test.
Rename funtions.

main.go

@@ -666,7 +666,7 @@ func buildBlacklist(files []*ast.File, info *types.Info, pkg *types.Package) map
 	}
 	visit := func(node ast.Node) bool {
 		if envGarbleLiterals {
-			strConstBlacklist(node, info, blacklist)
+			constBlacklist(node, info, blacklist)
 		}
 
 		if node == nil {

strings.go

@@ -316,49 +316,47 @@ func keyStmt(key []byte) *ast.GenDecl {
 	}
 }
 
-func strConstBlacklist(node ast.Node, info *types.Info, blacklist map[types.Object]struct{}) {
-	strType := types.Typ[types.String]
-	untypedStr := types.Typ[types.UntypedString]
+func constBlacklist(node ast.Node, info *types.Info, blacklist map[types.Object]struct{}) {
 
-	constCheck := func(node ast.Node) bool {
+	blacklistObjects := func(node ast.Node) bool {
 		ident, ok := node.(*ast.Ident)
 		if !ok {
 			return true
 		}
 
 		obj := info.ObjectOf(ident)
-		if obj.Type() == strType || obj.Type() == untypedStr {
-			blacklist[obj] = struct{}{}
-		}
+		blacklist[obj] = struct{}{}
+
 		return true
 	}
 
 	switch x := node.(type) {
+	// in a slice or array composite literal all explicit keys must be constant representable
 	case *ast.CompositeLit:
 		if _, ok := x.Type.(*ast.ArrayType); !ok {
 			break
 		}
 		for _, elt := range x.Elts {
 			if kv, ok := elt.(*ast.KeyValueExpr); ok {
-				ast.Inspect(kv.Key, constCheck)
+				ast.Inspect(kv.Key, blacklistObjects)
 			}
 		}
+	// in an array type the length must be a constant representable
 	case *ast.ArrayType:
 		if x.Len != nil {
-			ast.Inspect(x.Len, constCheck)
+			ast.Inspect(x.Len, blacklistObjects)
 		}
+
+	// in a const declaration all values must be constant representable
 	case *ast.GenDecl:
 		if x.Tok != token.CONST {
 			break
 		}
 		for _, spec := range x.Specs {
-			spec, ok := spec.(*ast.ValueSpec)
-			if !ok {
-				continue
-			}
+			spec := spec.(*ast.ValueSpec)
 
 			for _, val := range spec.Values {
-				ast.Inspect(val, constCheck)
+				ast.Inspect(val, blacklistObjects)
 			}
 		}
 	}

testdata/scripts/strings.txt

@@ -134,15 +134,18 @@ func constantTest() {
 
 	const d = "foo" // skip
 	var arr = [5]string{len(d): "foo"}
-
 	for _, elm := range arr {
-		println(elm)
+		if elm != "" {
+			println(elm)
+		}
 	}
 
 	const e = "foo" // skip
 	var slice = []string{len(e): "foo"}
 	for _, elm := range slice {
-		println(elm)
+		if elm != "" {
+			println(elm)
+		}
 	}
 
 	const f = "foo" // skip
@@ -171,12 +174,5 @@ stringTypeField String stringTypeField strType
 stringType lambda func return
 stringType func param
 stringType return
-
-
-
 foo
-
-
-
-
 foo