diff --git a/musttag.go b/musttag.go
index 5fb6bb5..1254288 100644
--- a/musttag.go
+++ b/musttag.go
@@ -81,9 +81,6 @@ func flags(funcs *[]Func) flag.FlagSet {
 
 // for tests only.
 var (
-	// should the same struct be reported only once for the same tag?
-	reportOnce = true
-
 	reportf = func(pass *analysis.Pass, st *structType, fn Func, fnPos token.Position) {
 		const format = "`%s` should be annotated with the `%s` tag as it is passed to `%s` at %s"
 		pass.Reportf(st.Pos, format, st.Name, fn.Tag, fn.shortName(), fnPos)
@@ -105,14 +102,6 @@ func run(pass *analysis.Pass, funcs map[string]Func) (any, error) {
 		modulePackages[pkg] = struct{}{}
 	}
 
-	// store previous reports to prevent reporting
-	// the same struct more than once (if reportOnce is true).
-	type report struct {
-		pos token.Pos // the position for report.
-		tag string    // the missing struct tag.
-	}
-	reports := make(map[report]struct{})
-
 	walk := pass.ResultOf[inspect.Analyzer].(*inspector.Inspector)
 	filter := []ast.Node{(*ast.CallExpr)(nil)}
 
@@ -168,15 +157,9 @@ func run(pass *analysis.Pass, funcs map[string]Func) (any, error) {
 			return // nothing to report.
 		}
 
-		r := report{result.Pos, fn.Tag}
-		if _, ok := reports[r]; ok && reportOnce {
-			return // already reported.
-		}
-
 		p := pass.Fset.Position(call.Pos())
 		p.Filename, _ = filepath.Rel(moduleDir, p.Filename)
 		reportf(pass, result, fn, p)
-		reports[r] = struct{}{}
 	})
 
 	return nil, nil
diff --git a/musttag_test.go b/musttag_test.go
index a671f09..459ccb1 100644
--- a/musttag_test.go
+++ b/musttag_test.go
@@ -25,18 +25,11 @@ func TestAnalyzer(t *testing.T) {
 	)
 
 	t.Run("builtins", func(t *testing.T) {
-		original := reportf
-		reportf = func(pass *analysis.Pass, st *structType, fn Func, fnPos token.Position) {
-			fnPos.Line = 0 // it's annoying to fix line numbers expectations when a new line is added.
-			original(pass, st, fn, fnPos)
-		}
 		testdata := analysistest.TestData()
 		analysistest.Run(t, testdata, analyzer, "builtins")
 	})
 
 	t.Run("tests", func(t *testing.T) {
-		// for the tests we want to record reports from all functions.
-		reportOnce = false
 		reportf = func(pass *analysis.Pass, st *structType, fn Func, fnPos token.Position) {
 			pass.Reportf(st.Pos, fn.shortName())
 		}
diff --git a/testdata/builtins.go b/testdata/builtins.go
index ce11bc2..98c8fae 100644
--- a/testdata/builtins.go
+++ b/testdata/builtins.go
@@ -11,15 +11,40 @@ import (
 	"gopkg.in/yaml.v3"
 )
 
-// TODO(junk1tm): drop `reportOnce` and test each builtin function.
-
 type User struct { /* want
 	"`User` should be annotated with the `json` tag as it is passed to `json.Marshal` at testdata/src/builtins/builtins.go"
+	"`User` should be annotated with the `json` tag as it is passed to `json.MarshalIndent` at testdata/src/builtins/builtins.go"
+	"`User` should be annotated with the `json` tag as it is passed to `json.Unmarshal` at testdata/src/builtins/builtins.go"
+	"`User` should be annotated with the `json` tag as it is passed to `json.Encoder.Encode` at testdata/src/builtins/builtins.go"
+	"`User` should be annotated with the `json` tag as it is passed to `json.Decoder.Decode` at testdata/src/builtins/builtins.go"
+
 	"`User` should be annotated with the `xml` tag as it is passed to `xml.Marshal` at testdata/src/builtins/builtins.go"
+	"`User` should be annotated with the `xml` tag as it is passed to `xml.MarshalIndent` at testdata/src/builtins/builtins.go"
+	"`User` should be annotated with the `xml` tag as it is passed to `xml.Unmarshal` at testdata/src/builtins/builtins.go"
+	"`User` should be annotated with the `xml` tag as it is passed to `xml.Encoder.Encode` at testdata/src/builtins/builtins.go"
+	"`User` should be annotated with the `xml` tag as it is passed to `xml.Decoder.Decode` at testdata/src/builtins/builtins.go"
+	"`User` should be annotated with the `xml` tag as it is passed to `xml.Encoder.EncodeElement` at testdata/src/builtins/builtins.go"
+	"`User` should be annotated with the `xml` tag as it is passed to `xml.Decoder.DecodeElement` at testdata/src/builtins/builtins.go"
+
 	"`User` should be annotated with the `yaml` tag as it is passed to `yaml.v3.Marshal` at testdata/src/builtins/builtins.go"
+	"`User` should be annotated with the `yaml` tag as it is passed to `yaml.v3.Unmarshal` at testdata/src/builtins/builtins.go"
+	"`User` should be annotated with the `yaml` tag as it is passed to `yaml.v3.Encoder.Encode` at testdata/src/builtins/builtins.go"
+	"`User` should be annotated with the `yaml` tag as it is passed to `yaml.v3.Decoder.Decode` at testdata/src/builtins/builtins.go"
+
 	"`User` should be annotated with the `toml` tag as it is passed to `toml.Unmarshal` at testdata/src/builtins/builtins.go"
+	"`User` should be annotated with the `toml` tag as it is passed to `toml.Decode` at testdata/src/builtins/builtins.go"
+	"`User` should be annotated with the `toml` tag as it is passed to `toml.DecodeFS` at testdata/src/builtins/builtins.go"
+	"`User` should be annotated with the `toml` tag as it is passed to `toml.DecodeFile` at testdata/src/builtins/builtins.go"
+	"`User` should be annotated with the `toml` tag as it is passed to `toml.Encoder.Encode` at testdata/src/builtins/builtins.go"
+	"`User` should be annotated with the `toml` tag as it is passed to `toml.Decoder.Decode` at testdata/src/builtins/builtins.go"
+
 	"`User` should be annotated with the `mapstructure` tag as it is passed to `mapstructure.Decode` at testdata/src/builtins/builtins.go"
+	"`User` should be annotated with the `mapstructure` tag as it is passed to `mapstructure.DecodeMetadata` at testdata/src/builtins/builtins.go"
+	"`User` should be annotated with the `mapstructure` tag as it is passed to `mapstructure.WeakDecode` at testdata/src/builtins/builtins.go"
+	"`User` should be annotated with the `mapstructure` tag as it is passed to `mapstructure.WeakDecodeMetadata` at testdata/src/builtins/builtins.go"
+
 	"`User` should be annotated with the `custom` tag as it is passed to `custom.Marshal` at testdata/src/builtins/builtins.go"
+	"`User` should be annotated with the `custom` tag as it is passed to `custom.Unmarshal` at testdata/src/builtins/builtins.go"
 	*/
 	Name  string
 	Email string `json:"email" xml:"email" yaml:"email" toml:"email" mapstructure:"email" custom:"email"`