Cannot validate incorrect types

[threesquared]

Describe the bug

When validating an input with an incorrect type we get an failed to decode json: json: cannot unmarshall... error instead of a validation failed error with a context object pointing to the issue. This is because the un-marshalling fails before the validator is even run.

To Reproduce

package main

import (
	"bytes"
	"context"
	"net/http"
	"net/http/httptest"
	"testing"

	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"
	"github.com/swaggest/rest/web"
	"github.com/swaggest/usecase"
)

func TestFoo(t *testing.T) {
	type TestInput struct {
		TestString string `json:"testString" default:"valid" required:"true" minLength:"5" maxLength:"10" pattern:"^[a-z]+$"`
	}

	s := web.DefaultService()

	s.Post("/foo", usecase.NewInteractor(func(ctx context.Context, input TestInput, output *string) error {
		*output = input.TestString

		return nil
	}))

	req, err := http.NewRequest(http.MethodPost, "/foo", bytes.NewReader([]byte(`{"testString":77}`)))
	require.NoError(t, err)
	req.Header.Set("Content-Type", "application/json")
	rw := httptest.NewRecorder()

	s.ServeHTTP(rw, req)
	assert.Contains(t, rw.Body.String(), "validation failed")
	assert.Equal(t, http.StatusBadRequest, rw.Code)
}

Expected behavior

I would expect a type mismatch issue to be reported in the same way as any other validation error to the end user