Fix cmg bug where type aliases are replaced by their underlying types (#540)

- The initial effort to support type aliases was pulling the underlying
  type of type aliases when generating type names and zero values, but
  that was not the correct behavior. This fix changes it so type aliases
  are treated the same way as named types.

Author: douglaswth

go.work.sum

@@ -2,6 +2,7 @@ cel.dev/expr v0.16.0/go.mod h1:TRSuuV7DlVCE/uwv5QbAiW/v8l5O8C4eEPHeu7gf7Sg=
 cel.dev/expr v0.16.2 h1:RwRhoH17VhAu9U5CMvMhH1PDVgf0tuz9FT+24AfMLfU=
 cel.dev/expr v0.16.2/go.mod h1:gXngZQMkWJoSbE8mOzehJlXQyubn/Vg0vR9/F3W7iw8=
 cel.dev/expr v0.19.0/go.mod h1:MrpN08Q+lEBs+bGYdLxxHkZoUSsCp0nSKTs0nTymJgw=
+cel.dev/expr v0.19.1/go.mod h1:MrpN08Q+lEBs+bGYdLxxHkZoUSsCp0nSKTs0nTymJgw=
 cloud.google.com/go v0.115.1/go.mod h1:DuujITeaufu3gL68/lOFIirVNJwQeyf5UXyi+Wbgknc=
 cloud.google.com/go v0.116.0 h1:B3fRrSDkLRt5qSHWe40ERJvhvnQwdZiHu0bJOpldweE=
 cloud.google.com/go v0.116.0/go.mod h1:cEPSRWPzZEswwdr9BxE6ChEn01dWlTaF05LiC2Xs70U=
@@ -90,6 +91,7 @@ cloud.google.com/go/compute/metadata v0.3.0/go.mod h1:zFmK7XCadkQkj6TtorcaGlCW1h
 cloud.google.com/go/compute/metadata v0.5.0/go.mod h1:aHnloV2TPI38yx4s9+wAZhHykWvVCfu7hQbF+9CWoiY=
 cloud.google.com/go/compute/metadata v0.5.2 h1:UxK4uu/Tn+I3p2dYWTfiX4wva7aYlKixAHn3fyqngqo=
 cloud.google.com/go/compute/metadata v0.5.2/go.mod h1:C66sj2AluDcIqakBq/M8lw8/ybHgOZqin2obFxa/E5k=
+cloud.google.com/go/compute/metadata v0.6.0/go.mod h1:FjyFAW1MW0C203CEOMDTu3Dk1FlqW3Rga40jzHL4hfg=
 cloud.google.com/go/contactcenterinsights v1.14.1/go.mod h1:OxSWVQxosMh18KCQ3D5UZWYxVrOcK9xrJCV5waxD2dY=
 cloud.google.com/go/contactcenterinsights v1.15.0 h1:jHwyL2TQTaLauRRz5Uv7/sL7PNAK1VAMy/UIT9vsFzk=
 cloud.google.com/go/contactcenterinsights v1.15.0/go.mod h1:6bJGBQrJsnATv2s6Dh/c6HCRanq2kCZ0kIIjRV1G0mI=
@@ -373,7 +375,6 @@ github.com/antihax/optional v1.0.0 h1:xK2lYat7ZLaVVcIuj82J8kIro4V6kDe0AUDFboUCwc
 github.com/antihax/optional v1.0.0/go.mod h1:uupD/76wgC+ih3iEmQUL+0Ugr19nfwCT1kdvxnR2qWY=
 github.com/aws/aws-lambda-go v1.47.0 h1:0H8s0vumYx/YKs4sE7YM0ktwL2eWse+kfopsRI1sXVI=
 github.com/aws/aws-lambda-go v1.47.0/go.mod h1:dpMpZgvWx5vuQJfBt0zqBha60q7Dd7RfgJv23DymV8A=
-github.com/aws/smithy-go v1.22.2/go.mod h1:irrKGvNn1InZwb2d7fkIRNucdfwR8R+Ts3wxYa/cJHg=
 github.com/bazelbuild/rules_go v0.49.0 h1:5vCbuvy8Q11g41lseGJDc5vxhDjJtfxr6nM/IC4VmqM=
 github.com/bazelbuild/rules_go v0.49.0/go.mod h1:Dhcz716Kqg1RHNWos+N6MlXNkjNP2EwZQ0LukRKJfMs=
 github.com/census-instrumentation/opencensus-proto v0.4.1 h1:iKLQ0xPNFxR/2hzXZMrBo8f1j86j5WHzznCCQxV/b8g=
@@ -383,14 +384,19 @@ github.com/cespare/xxhash/v2 v2.3.0/go.mod h1:VGX0DQ3Q6kWi7AoAeZDth3/j3BFtOZR5XL
 github.com/cncf/xds/go v0.0.0-20240723142845-024c85f92f20/go.mod h1:W+zGtBO5Y1IgJhy4+A9GOqVhqLpfZi+vwmdNXUehLA8=
 github.com/cncf/xds/go v0.0.0-20240905190251-b4127c9b8d78 h1:QVw89YDxXxEe+l8gU8ETbOasdwEV+avkR75ZzsVV9WI=
 github.com/cncf/xds/go v0.0.0-20240905190251-b4127c9b8d78/go.mod h1:W+zGtBO5Y1IgJhy4+A9GOqVhqLpfZi+vwmdNXUehLA8=
+github.com/cncf/xds/go v0.0.0-20241223141626-cff3c89139a3/go.mod h1:W+zGtBO5Y1IgJhy4+A9GOqVhqLpfZi+vwmdNXUehLA8=
 github.com/creack/pty v1.1.9 h1:uDmaGzcdjhF4i/plgjmEsriH11Y0o7RKapEf/LDaM3w=
 github.com/creack/pty v1.1.9/go.mod h1:oKZEueFk5CKHvIhNR5MUki03XCEU+Q6VDXinZuGJ33E=
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/envoyproxy/go-control-plane v0.13.0/go.mod h1:GRaKG3dwvFoTg4nj7aXdZnvMg4d7nvT/wl9WgVXn3Q8=
 github.com/envoyproxy/go-control-plane v0.13.1 h1:vPfJZCkob6yTMEgS+0TwfTUfbHjfy/6vOJ8hUWX/uXE=
 github.com/envoyproxy/go-control-plane v0.13.1/go.mod h1:X45hY0mufo6Fd0KW3rqsGvQMw58jvjymeCzBU3mWyHw=
+github.com/envoyproxy/go-control-plane v0.13.4/go.mod h1:kDfuBlDVsSj2MjrLEtRWtHlsWIFcGyB2RMO44Dc5GZA=
+github.com/envoyproxy/go-control-plane/envoy v1.32.4/go.mod h1:Gzjc5k8JcJswLjAx1Zm+wSYE20UrLtt7JZMWiWQXQEw=
+github.com/envoyproxy/go-control-plane/ratelimit v0.1.0/go.mod h1:Wk+tMFAFbCXaJPzVVHnPgRKdUdwW/KdbRt94AzgRee4=
 github.com/envoyproxy/protoc-gen-validate v1.1.0 h1:tntQDh69XqOCOZsDz0lVJQez/2L6Uu2PdjCQwWCJ3bM=
 github.com/envoyproxy/protoc-gen-validate v1.1.0/go.mod h1:sXRDRVmzEbkM7CVcM06s9shE/m23dg3wzjl0UWqJ2q4=
+github.com/envoyproxy/protoc-gen-validate v1.2.1/go.mod h1:d/C80l/jxXLdfEIhX1W2TmLfsJ31lvEjwamM4DxlWXU=
 github.com/fsnotify/fsnotify v1.7.0 h1:8JEhPFa5W2WU7YfeZzPNqzMP6Lwt7L2715Ggo0nosvA=
 github.com/fsnotify/fsnotify v1.7.0/go.mod h1:40Bi/Hjc2AVfZrqy+aj+yEI+/bRxZnMJyTJwOpGvigM=
 github.com/getkin/kin-openapi v0.127.0 h1:Mghqi3Dhryf3F8vR370nN67pAERW+3a95vomb3MAREY=
@@ -408,17 +414,16 @@ github.com/go-openapi/swag v0.23.0/go.mod h1:esZ8ITTYEsH1V2trKHjAN8Ai7xHb8RV+YSZ
 github.com/go-test/deep v1.0.8 h1:TDsG77qcSprGbC6vTN8OuXp5g+J+b5Pcguhf7Zt61VM=
 github.com/go-test/deep v1.0.8/go.mod h1:5C2ZWiW0ErCdrYzpqxLbTX7MG14M9iiw8DgHncVwcsE=
 github.com/gohugoio/hashstructure v0.3.0/go.mod h1:8ohPTAfQLTs2WdzB6k9etmQYclDUeNsIHGPAFejbsEA=
-github.com/gohugoio/hashstructure v0.5.0/go.mod h1:Ser0TniXuu/eauYmrwM4o64EBvySxNzITEOLlm4igec=
 github.com/golang/glog v1.2.2 h1:1+mZ9upx1Dh6FmUTFR1naJ77miKiXgALjWOZ3NVFPmY=
 github.com/golang/glog v1.2.2/go.mod h1:6AhwSGph0fcJtXVM/PEHPqZlFeoLxhs7/t5UDAwmO+w=
 github.com/golang/glog v1.2.3/go.mod h1:6AhwSGph0fcJtXVM/PEHPqZlFeoLxhs7/t5UDAwmO+w=
+github.com/golang/glog v1.2.4/go.mod h1:6AhwSGph0fcJtXVM/PEHPqZlFeoLxhs7/t5UDAwmO+w=
 github.com/golang/protobuf v1.5.0/go.mod h1:FsONVRAS9T7sI+LIUmWTfcYkHO4aIWwzhcaSAoJOfIk=
 github.com/golang/protobuf v1.5.3/go.mod h1:XVQd3VNwM+JqD3oG2Ue2ip4fOMUkwXdXDdiuN0vRsmY=
 github.com/google/go-cmp v0.5.5/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
 github.com/google/go-cmp v0.5.9/go.mod h1:17dUlkBOakJ0+DkrSSNjCkIjxS6bF9zb3elmeNGIjoY=
 github.com/gorilla/mux v1.8.0 h1:i40aqfkR1h2SlN9hojwV5ZA91wcXFOvkdNIeFDP5koI=
 github.com/gorilla/mux v1.8.0/go.mod h1:DVbg23sWSpFRCP0SfiEN6jmj59UnW/n46BH5rLB71So=
-github.com/grpc-ecosystem/grpc-gateway/v2 v2.25.1/go.mod h1:RBRO7fro65R6tjKzYgLAFo0t1QEXY1Dp+i/bvpRiqiQ=
 github.com/iancoleman/strcase v0.3.0 h1:nTXanmYxhfFAMjZL34Ov6gkzEsSJZ5DbhxWjvSASxEI=
 github.com/iancoleman/strcase v0.3.0/go.mod h1:iwCmte+B7n89clKwxIoIXy/HfoL7AsD47ZCWhYzw7ho=
 github.com/invopop/yaml v0.3.1 h1:f0+ZpmhfBSS4MhG+4HYseMdJhoeeopbSKbq5Rpeelso=
@@ -452,6 +457,7 @@ github.com/planetscale/vtprotobuf v0.6.1-0.20240319094008-0393e58bdf10 h1:GFCKgm
 github.com/planetscale/vtprotobuf v0.6.1-0.20240319094008-0393e58bdf10/go.mod h1:t/avpk3KcrXxUnYOhZhMXJlSEyie6gQbtLq5NM3loB8=
 github.com/prometheus/client_model v0.6.0 h1:k1v3CzpSRUTrKMppY35TLwPvxHqBu0bYgxZzqGIgaos=
 github.com/prometheus/client_model v0.6.0/go.mod h1:NTQHnmxFpouOD0DpvP4XujX3CdOAGQPoaGhyTchlyt8=
+github.com/prometheus/client_model v0.6.1/go.mod h1:OrxVMOVHjw3lKMa8+x6HeMGkHMQyHDk9E3jmP2AmGiY=
 github.com/rogpeppe/fastuuid v1.2.0 h1:Ppwyp6VYCF1nvBTXL3trRso7mXMlRrw9ooo375wvi2s=
 github.com/rogpeppe/fastuuid v1.2.0/go.mod h1:jVj6XXZzXRy/MSR5jhDC/2q6DgLz+nrA6LYCDYWNEvQ=
 github.com/rogpeppe/go-internal v1.9.0/go.mod h1:WtVeX8xhTBvf0smdhujwtBcq4Qrzq/fJaraNFVN+nFs=
@@ -470,8 +476,8 @@ github.com/yuin/goldmark v1.4.13/go.mod h1:6yULJ656Px+3vBD8DxQVa3kxgyrAnzto9xy5t
 go.opentelemetry.io/contrib/detectors/gcp v1.31.0 h1:G1JQOreVrfhRkner+l4mrGxmfqYCAuy76asTDAo0xsA=
 go.opentelemetry.io/contrib/detectors/gcp v1.31.0/go.mod h1:tzQL6E1l+iV44YFTkcAeNQqzXUiekSYP9jjJjXwEd00=
 go.opentelemetry.io/contrib/detectors/gcp v1.32.0/go.mod h1:TVqo0Sda4Cv8gCIixd7LuLwW4EylumVWfhjZJjDD4DU=
+go.opentelemetry.io/contrib/detectors/gcp v1.34.0/go.mod h1:cV4BMFcscUR/ckqLkbfQmF0PRsq8w/lMGzdbCSveBHo=
 go.opentelemetry.io/otel v1.32.0/go.mod h1:00DCVSB0RQcnzlwyTfqtxSm+DRr9hpYrHjNGiBHVQIg=
-go.opentelemetry.io/otel/exporters/stdout/stdoutmetric v1.32.0/go.mod h1:fdWW0HtZJ7+jNpTKUR0GpMEDP69nR8YBJQxNiVCE3jk=
 go.opentelemetry.io/otel/metric v1.32.0/go.mod h1:jH7CIbbK6SH2V2wE16W05BHCtIDzauciCRLoc/SyMv8=
 go.opentelemetry.io/otel/sdk v1.32.0/go.mod h1:LqgegDBjKMmb2GC6/PrTnteJG39I8/vJCAP9LlJXEjU=
 go.opentelemetry.io/otel/sdk/metric v1.32.0/go.mod h1:PWeZlq0zt9YkYAp3gjKZ0eicRYvOh1Gd+X99x6GHpCQ=
@@ -488,6 +494,7 @@ golang.org/x/crypto v0.28.0/go.mod h1:rmgy+3RHxRZMyY0jjAJShp2zgEdOqj2AO7U0pYmeQ7
 golang.org/x/crypto v0.32.0 h1:euUpcYgM8WcP71gNpTqQCn6rC2t6ULUPiOzfWaXVVfc=
 golang.org/x/crypto v0.32.0/go.mod h1:ZnnJkOaASj8g0AjIduWNlq2NRxL0PlBrbKVyZ6V/Ugc=
 golang.org/x/crypto v0.33.0/go.mod h1:bVdXmD7IV/4GdElGPozy6U7lWdRXA4qyRVGJV57uQ5M=
+golang.org/x/crypto v0.36.0/go.mod h1:Y4J0ReaxCR1IMaabaSMugxJES1EpwhBHhv2bDHklZvc=
 golang.org/x/mod v0.17.0/go.mod h1:hTbmBsO62+eylJbnUtE2MGJUyE7QWk4xUqPFrRgJ+7c=
 golang.org/x/mod v0.22.0/go.mod h1:6SkKJ3Xj0I0BrPOZoBy3bdMptDDU9oJrpohJ3eWZ1fY=
 golang.org/x/net v0.28.0/go.mod h1:yqtgsTWOOnlGLG9GFRrK3++bGOUEkNBoHZc8MEDWPNg=
@@ -496,10 +503,12 @@ golang.org/x/net v0.30.0/go.mod h1:2wGyMJ5iFasEhkwi13ChkO/t1ECNC4X4eBKkVFyYFlU=
 golang.org/x/net v0.32.0/go.mod h1:CwU0IoeOlnQQWJ6ioyFrfRuomB8GKF6KbYXZVyeXNfs=
 golang.org/x/net v0.33.0/go.mod h1:HXLR5J+9DxmrqMwG9qjGCxZ+zKXxBru04zlTvWlWuN4=
 golang.org/x/net v0.34.0/go.mod h1:di0qlW3YNM5oh6GqDGQr92MyTozJPmybPK4Ev/Gm31k=
+golang.org/x/net v0.35.0/go.mod h1:EglIi67kWsHKlRzzVMUD93VMSWGFOMSZgxFjparz1Qk=
 golang.org/x/oauth2 v0.22.0/go.mod h1:XYTD2NtWslqkgxebSiOHnXEap4TF09sJSc7H1sXbhtI=
 golang.org/x/oauth2 v0.23.0/go.mod h1:XYTD2NtWslqkgxebSiOHnXEap4TF09sJSc7H1sXbhtI=
 golang.org/x/oauth2 v0.24.0 h1:KTBBxWqUa0ykRPLtV69rRto9TLXcqYkeswu48x/gvNE=
 golang.org/x/oauth2 v0.24.0/go.mod h1:XYTD2NtWslqkgxebSiOHnXEap4TF09sJSc7H1sXbhtI=
+golang.org/x/oauth2 v0.25.0/go.mod h1:XYTD2NtWslqkgxebSiOHnXEap4TF09sJSc7H1sXbhtI=
 golang.org/x/oauth2 v0.26.0/go.mod h1:XYTD2NtWslqkgxebSiOHnXEap4TF09sJSc7H1sXbhtI=
 golang.org/x/sync v0.8.0/go.mod h1:Czt+wKu1gCyEFDUtn0jG5QVvpJ6rzVqr5aXyt9drQfk=
 golang.org/x/sync v0.10.0/go.mod h1:Czt+wKu1gCyEFDUtn0jG5QVvpJ6rzVqr5aXyt9drQfk=
@@ -528,8 +537,9 @@ google.golang.org/genproto/googleapis/api v0.0.0-20241015192408-796eee8c2d53/go.
 google.golang.org/genproto/googleapis/api v0.0.0-20241202173237-19429a94021a/go.mod h1:jehYqy3+AhJU9ve55aNOaSml7wUXjF9x6z2LcCfpAhY=
 google.golang.org/genproto/googleapis/api v0.0.0-20241219192143-6b3ec007d9bb/go.mod h1:E5//3O5ZIG2l71Xnt+P/CYUY8Bxs8E7WMoZ9tlcMbAY=
 google.golang.org/genproto/googleapis/api v0.0.0-20250102185135-69823020774d/go.mod h1:2v7Z7gP2ZUOGsaFyxATQSRoBnKygqVq2Cwnvom7QiqY=
-google.golang.org/genproto/googleapis/api v0.0.0-20250115164207-1a7da9e5054f/go.mod h1:Ic02D47M+zbarjYYUlK57y316f2MoN0gjAwI3f2S95o=
+google.golang.org/genproto/googleapis/api v0.0.0-20250106144421-5f5ef82da422/go.mod h1:b6h1vNKhxaSoEI+5jc3PJUCustfli/mRab7295pY7rw=
 google.golang.org/genproto/googleapis/api v0.0.0-20250204164813-702378808489/go.mod h1:iYONQfRdizDB8JJBybql13nArx91jcUk7zCXEsOofM4=
+google.golang.org/genproto/googleapis/api v0.0.0-20250218202821-56aae31c358a/go.mod h1:3kWAYMk1I75K4vykHtKt2ycnOgpA6974V7bREqbsenU=
 google.golang.org/genproto/googleapis/rpc v0.0.0-20240814211410-ddb44dafa142/go.mod h1:UqMtugtsSgubUsoxbuAoiCXvqvErP7Gf0so0mK9tHxU=
 google.golang.org/genproto/googleapis/rpc v0.0.0-20240903143218-8af14fe29dc1/go.mod h1:UqMtugtsSgubUsoxbuAoiCXvqvErP7Gf0so0mK9tHxU=
 google.golang.org/genproto/googleapis/rpc v0.0.0-20240930140551-af27646dc61f/go.mod h1:UqMtugtsSgubUsoxbuAoiCXvqvErP7Gf0so0mK9tHxU=
@@ -541,6 +551,7 @@ google.golang.org/genproto/googleapis/rpc v0.0.0-20250106144421-5f5ef82da422/go.
 google.golang.org/genproto/googleapis/rpc v0.0.0-20250115164207-1a7da9e5054f/go.mod h1:+2Yz8+CLJbIfL9z73EW45avw8Lmge3xVElCP9zEKi50=
 google.golang.org/genproto/googleapis/rpc v0.0.0-20250204164813-702378808489/go.mod h1:8BS3B93F/U1juMFq9+EDk+qOT5CO1R9IzXxG3PTqiRk=
 google.golang.org/genproto/googleapis/rpc v0.0.0-20250212204824-5a70512c5d8b/go.mod h1:8BS3B93F/U1juMFq9+EDk+qOT5CO1R9IzXxG3PTqiRk=
+google.golang.org/genproto/googleapis/rpc v0.0.0-20250218202821-56aae31c358a/go.mod h1:uRxBH1mhmO8PGhU89cMcHaXKZqO+OfakD8QQO0oYwlQ=
 google.golang.org/grpc v1.67.0/go.mod h1:1gLDyUQU7CTLJI90u3nXZ9ekeghjeM7pTDZlqFNg2AA=
 google.golang.org/grpc v1.67.1/go.mod h1:1gLDyUQU7CTLJI90u3nXZ9ekeghjeM7pTDZlqFNg2AA=
 google.golang.org/grpc v1.69.2/go.mod h1:vyjdE6jLBI76dgpDojsFGNaHlxdjXN9ghpnd2o7JGZ4=

mock/cmd/cmg/pkg/generate/_tests/extensive/extensive.go

@@ -38,6 +38,8 @@ type (
 		NamedTypes(Struct, Array, io.Reader, imported.Type, goa.Endpoint, Generic[uint, string, Struct, Array]) (Struct, Array, io.Reader, imported.Type, goa.Endpoint, Generic[uint, string, Struct, Array])
 		FuncNamedTypes(func(Struct, Array, io.Reader, imported.Type, goa.Endpoint, Generic[uint, string, Struct, Array])) func(Struct, Array, io.Reader, imported.Type, goa.Endpoint, Generic[uint, string, Struct, Array])
 		VariableConflicts(f, m uint)
+		AliasedTypes(IntAlias, ArrayAlias, StructAlias, IntSetAlias, SetAlias[string]) (IntAlias, ArrayAlias, StructAlias, IntSetAlias, SetAlias[string])
+		AliasedFuncTypes(func(IntAlias, ArrayAlias, StructAlias, IntSetAlias, SetAlias[string])) func(IntAlias, ArrayAlias, StructAlias, IntSetAlias, SetAlias[string])
 
 		Embedded
 		imported.Interface
@@ -52,7 +54,12 @@ type (
 		Complex(map[K]V, []X, *Y, Set[K]) (map[K]V, []X, *Y, Set[K])
 	}
 
-	Struct            struct{}
-	Array             [5]Struct
-	Set[K comparable] map[K]Struct
+	Struct                 struct{ A, B int }
+	Array                  [5]Struct
+	Set[K comparable]      map[K]Struct
+	IntAlias               = int
+	ArrayAlias             = [5]Struct
+	StructAlias            = struct{ A, B int }
+	IntSetAlias            = Set[int]
+	SetAlias[K comparable] = Set[K]
 )

mock/cmd/cmg/pkg/generate/_tests/extensive/mocks/extensive.go

@@ -29,7 +29,20 @@ func (ta *typeAdder) name(tt types.Type) (name string) {
 	if !ok {
 		switch t := tt.(type) {
 		case *types.Alias:
-			name = ta.name(t.Underlying())
+			o := t.Obj()
+			if p := o.Pkg(); p != nil {
+				i := addImport(newImport(p.Path(), p.Name()), ta.stdImports, ta.extImports, ta.intImports, ta.modPath)
+				name = fmt.Sprintf("%v.%v", i.AliasOrPkgName(), o.Name())
+			} else {
+				name = o.Name()
+			}
+			if tas := t.TypeArgs(); tas != nil {
+				as := make([]string, 0, tas.Len())
+				for i := 0; i < tas.Len(); i++ {
+					as = append(as, ta.name(tas.At(i)))
+				}
+				name += "[" + strings.Join(as, ", ") + "]"
+			}
 		case *types.Array:
 			name = fmt.Sprintf("[%v]%v", t.Len(), ta.name(t.Elem()))
 		case *types.Basic:
@@ -137,7 +150,12 @@ func (ta *typeAdder) zero(tt types.Type) (zero string) {
 	if !ok {
 		switch t := tt.(type) {
 		case *types.Alias:
-			zero = ta.zero(t.Underlying())
+			switch t.Underlying().(type) {
+			case *types.Array, *types.Struct:
+				zero = ta.name(t) + "{}"
+			default:
+				zero = ta.zero(t.Underlying())
+			}
 		case *types.Array, *types.Struct:
 			zero = ta.name(t) + "{}"
 		case *types.Basic: