diff --git a/Cargo.lock b/Cargo.lock
index 51b0da65b3145..a6d7eb4514d48 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -3663,7 +3663,6 @@ dependencies = [
  "libloading",
  "measureme 10.0.0",
  "rustc-demangle",
- "rustc_arena",
  "rustc_ast",
  "rustc_attr",
  "rustc_codegen_ssa",
@@ -3785,7 +3784,6 @@ dependencies = [
  "rustc_ast",
  "rustc_ast_pretty",
  "rustc_codegen_ssa",
- "rustc_const_eval",
  "rustc_data_structures",
  "rustc_error_codes",
  "rustc_errors",
@@ -3800,7 +3798,6 @@ dependencies = [
  "rustc_parse",
  "rustc_plugin_impl",
  "rustc_save_analysis",
- "rustc_serialize",
  "rustc_session",
  "rustc_span",
  "rustc_target",
@@ -3896,7 +3893,6 @@ dependencies = [
  "rustc_ast",
  "rustc_data_structures",
  "rustc_error_messages",
- "rustc_feature",
  "rustc_index",
  "rustc_macros",
  "rustc_serialize",
@@ -3957,7 +3953,6 @@ dependencies = [
  "rustc_macros",
  "rustc_middle",
  "rustc_serialize",
- "rustc_session",
  "rustc_span",
  "rustc_target",
  "smallvec",
@@ -4191,7 +4186,6 @@ dependencies = [
  "rustc_index",
  "rustc_middle",
  "rustc_serialize",
- "rustc_session",
  "rustc_span",
  "rustc_target",
  "smallvec",
@@ -4213,7 +4207,6 @@ dependencies = [
  "rustc_index",
  "rustc_middle",
  "rustc_mir_dataflow",
- "rustc_query_system",
  "rustc_serialize",
  "rustc_session",
  "rustc_span",
@@ -4228,7 +4221,6 @@ name = "rustc_monomorphize"
 version = "0.0.0"
 dependencies = [
  "rustc_data_structures",
- "rustc_errors",
  "rustc_hir",
  "rustc_index",
  "rustc_middle",
@@ -4280,7 +4272,6 @@ dependencies = [
  "rustc_index",
  "rustc_lexer",
  "rustc_middle",
- "rustc_parse",
  "rustc_serialize",
  "rustc_session",
  "rustc_span",
@@ -4295,10 +4286,8 @@ dependencies = [
  "libloading",
  "rustc_ast",
  "rustc_errors",
- "rustc_hir",
  "rustc_lint",
  "rustc_metadata",
- "rustc_middle",
  "rustc_session",
  "rustc_span",
 ]
@@ -4337,7 +4326,6 @@ dependencies = [
  "rustc_serialize",
  "rustc_session",
  "rustc_span",
- "rustc_type_ir",
  "tracing",
 ]
 
@@ -4359,7 +4347,6 @@ dependencies = [
  "rustc_session",
  "rustc_span",
  "rustc_target",
- "rustc_type_ir",
  "smallvec",
  "tracing",
 ]
@@ -4464,7 +4451,6 @@ dependencies = [
  "rustc_data_structures",
  "rustc_hir",
  "rustc_middle",
- "rustc_query_system",
  "rustc_session",
  "rustc_span",
  "rustc_target",
diff --git a/compiler/rustc_codegen_llvm/Cargo.toml b/compiler/rustc_codegen_llvm/Cargo.toml
index 67183ff5887e9..383bd8ab7bad7 100644
--- a/compiler/rustc_codegen_llvm/Cargo.toml
+++ b/compiler/rustc_codegen_llvm/Cargo.toml
@@ -16,7 +16,6 @@ measureme = "10.0.0"
 tracing = "0.1"
 rustc_middle = { path = "../rustc_middle" }
 rustc-demangle = "0.1.21"
-rustc_arena = { path = "../rustc_arena" }
 rustc_attr = { path = "../rustc_attr" }
 rustc_codegen_ssa = { path = "../rustc_codegen_ssa" }
 rustc_data_structures = { path = "../rustc_data_structures" }
diff --git a/compiler/rustc_driver/Cargo.toml b/compiler/rustc_driver/Cargo.toml
index a2cbd9abc9047..08d5d4f343c77 100644
--- a/compiler/rustc_driver/Cargo.toml
+++ b/compiler/rustc_driver/Cargo.toml
@@ -7,7 +7,6 @@ edition = "2021"
 crate-type = ["dylib"]
 
 [dependencies]
-libc = "0.2"
 tracing = { version = "0.1.28" }
 serde_json = "1.0.59"
 rustc_log = { path = "../rustc_log" }
@@ -21,7 +20,6 @@ rustc_feature = { path = "../rustc_feature" }
 rustc_hir = { path = "../rustc_hir" }
 rustc_hir_pretty = { path = "../rustc_hir_pretty" }
 rustc_metadata = { path = "../rustc_metadata" }
-rustc_const_eval = { path = "../rustc_const_eval" }
 rustc_parse = { path = "../rustc_parse" }
 rustc_plugin_impl = { path = "../rustc_plugin_impl" }
 rustc_save_analysis = { path = "../rustc_save_analysis" }
@@ -29,11 +27,13 @@ rustc_codegen_ssa = { path = "../rustc_codegen_ssa" }
 rustc_session = { path = "../rustc_session" }
 rustc_error_codes = { path = "../rustc_error_codes" }
 rustc_interface = { path = "../rustc_interface" }
-rustc_serialize = { path = "../rustc_serialize" }
 rustc_ast = { path = "../rustc_ast" }
 rustc_span = { path = "../rustc_span" }
 rustc_typeck = { path = "../rustc_typeck" }
 
+[target.'cfg(unix)'.dependencies]
+libc = "0.2"
+
 [target.'cfg(windows)'.dependencies]
 winapi = { version = "0.3", features = ["consoleapi", "debugapi", "processenv"] }
 
diff --git a/compiler/rustc_hir/Cargo.toml b/compiler/rustc_hir/Cargo.toml
index 34d366f401332..47ace7ca3a750 100644
--- a/compiler/rustc_hir/Cargo.toml
+++ b/compiler/rustc_hir/Cargo.toml
@@ -8,7 +8,6 @@ doctest = false
 
 [dependencies]
 rustc_target = { path = "../rustc_target" }
-rustc_feature = { path = "../rustc_feature" }
 rustc_macros = { path = "../rustc_macros" }
 rustc_data_structures = { path = "../rustc_data_structures" }
 rustc_error_messages = { path = "../rustc_error_messages" }
diff --git a/compiler/rustc_infer/Cargo.toml b/compiler/rustc_infer/Cargo.toml
index f87ea43b1a72c..bbc2b76773471 100644
--- a/compiler/rustc_infer/Cargo.toml
+++ b/compiler/rustc_infer/Cargo.toml
@@ -14,7 +14,6 @@ rustc_errors = { path = "../rustc_errors" }
 rustc_hir = { path = "../rustc_hir" }
 rustc_index = { path = "../rustc_index" }
 rustc_macros = { path = "../rustc_macros" }
-rustc_session = { path = "../rustc_session" }
 rustc_serialize = { path = "../rustc_serialize" }
 rustc_span = { path = "../rustc_span" }
 rustc_target = { path = "../rustc_target" }
diff --git a/compiler/rustc_interface/Cargo.toml b/compiler/rustc_interface/Cargo.toml
index 47dc5f2ef8670..26b1b9948a047 100644
--- a/compiler/rustc_interface/Cargo.toml
+++ b/compiler/rustc_interface/Cargo.toml
@@ -7,7 +7,6 @@ edition = "2021"
 doctest = false
 
 [dependencies]
-libc = "0.2"
 libloading = "0.7.1"
 tracing = "0.1"
 rustc-rayon-core = { version = "0.4.0", optional = true }
@@ -49,6 +48,9 @@ rustc_trait_selection = { path = "../rustc_trait_selection" }
 rustc_ty_utils = { path = "../rustc_ty_utils" }
 tempfile = "3.2"
 
+[target.'cfg(unix)'.dependencies]
+libc = "0.2"
+
 [target.'cfg(windows)'.dependencies]
 winapi = { version = "0.3", features = ["libloaderapi"] }
 
diff --git a/compiler/rustc_mir_dataflow/Cargo.toml b/compiler/rustc_mir_dataflow/Cargo.toml
index ffd7e3cd06bd2..a0c70a3fd81f1 100644
--- a/compiler/rustc_mir_dataflow/Cargo.toml
+++ b/compiler/rustc_mir_dataflow/Cargo.toml
@@ -18,6 +18,5 @@ rustc_hir = { path = "../rustc_hir" }
 rustc_index = { path = "../rustc_index" }
 rustc_middle = { path = "../rustc_middle" }
 rustc_serialize = { path = "../rustc_serialize" }
-rustc_session = { path = "../rustc_session" }
 rustc_target = { path = "../rustc_target" }
 rustc_span = { path = "../rustc_span" }
diff --git a/compiler/rustc_mir_transform/Cargo.toml b/compiler/rustc_mir_transform/Cargo.toml
index 4c1a7eaf6f03b..8a8098e9ab996 100644
--- a/compiler/rustc_mir_transform/Cargo.toml
+++ b/compiler/rustc_mir_transform/Cargo.toml
@@ -19,7 +19,6 @@ rustc_index = { path = "../rustc_index" }
 rustc_middle = { path = "../rustc_middle" }
 rustc_const_eval = { path = "../rustc_const_eval" }
 rustc_mir_dataflow = { path = "../rustc_mir_dataflow" }
-rustc_query_system = { path = "../rustc_query_system" }
 rustc_serialize = { path = "../rustc_serialize" }
 rustc_session = { path = "../rustc_session" }
 rustc_target = { path = "../rustc_target" }
diff --git a/compiler/rustc_monomorphize/Cargo.toml b/compiler/rustc_monomorphize/Cargo.toml
index f812afe6b62ba..e4ac47f4982cb 100644
--- a/compiler/rustc_monomorphize/Cargo.toml
+++ b/compiler/rustc_monomorphize/Cargo.toml
@@ -10,7 +10,6 @@ doctest = false
 smallvec = { version = "1.6.1", features = ["union", "may_dangle"] }
 tracing = "0.1"
 rustc_data_structures = { path = "../rustc_data_structures" }
-rustc_errors = { path = "../rustc_errors" }
 rustc_hir = { path = "../rustc_hir" }
 rustc_index = { path = "../rustc_index" }
 rustc_middle = { path = "../rustc_middle" }
diff --git a/compiler/rustc_passes/Cargo.toml b/compiler/rustc_passes/Cargo.toml
index a3ef1981e84f9..787d37277c6c0 100644
--- a/compiler/rustc_passes/Cargo.toml
+++ b/compiler/rustc_passes/Cargo.toml
@@ -12,7 +12,6 @@ rustc_errors = { path = "../rustc_errors" }
 rustc_expand = { path = "../rustc_expand" }
 rustc_hir = { path = "../rustc_hir" }
 rustc_index = { path = "../rustc_index" }
-rustc_parse = { path = "../rustc_parse" }
 rustc_session = { path = "../rustc_session" }
 rustc_target = { path = "../rustc_target" }
 rustc_ast = { path = "../rustc_ast" }
diff --git a/compiler/rustc_plugin_impl/Cargo.toml b/compiler/rustc_plugin_impl/Cargo.toml
index f5071eb6e8f96..b6ea533c80bdd 100644
--- a/compiler/rustc_plugin_impl/Cargo.toml
+++ b/compiler/rustc_plugin_impl/Cargo.toml
@@ -9,9 +9,7 @@ doctest = false
 
 [dependencies]
 libloading = "0.7.1"
-rustc_middle = { path = "../rustc_middle" }
 rustc_errors = { path = "../rustc_errors" }
-rustc_hir = { path = "../rustc_hir" }
 rustc_lint = { path = "../rustc_lint" }
 rustc_metadata = { path = "../rustc_metadata" }
 rustc_ast = { path = "../rustc_ast" }
diff --git a/compiler/rustc_query_impl/Cargo.toml b/compiler/rustc_query_impl/Cargo.toml
index 856f09b6fcc32..5673bb83b15f4 100644
--- a/compiler/rustc_query_impl/Cargo.toml
+++ b/compiler/rustc_query_impl/Cargo.toml
@@ -20,7 +20,6 @@ rustc_query_system = { path = "../rustc_query_system" }
 rustc_serialize = { path = "../rustc_serialize" }
 rustc_session = { path = "../rustc_session" }
 rustc_span = { path = "../rustc_span" }
-rustc_type_ir = { path = "../rustc_type_ir" }
 tracing = "0.1"
 
 [features]
diff --git a/compiler/rustc_query_system/Cargo.toml b/compiler/rustc_query_system/Cargo.toml
index 85fbb08eeeb53..b5a37cf324b00 100644
--- a/compiler/rustc_query_system/Cargo.toml
+++ b/compiler/rustc_query_system/Cargo.toml
@@ -21,7 +21,6 @@ rustc_serialize = { path = "../rustc_serialize" }
 rustc_session = { path = "../rustc_session" }
 rustc_span = { path = "../rustc_span" }
 rustc_target = { path = "../rustc_target" }
-rustc_type_ir = { path = "../rustc_type_ir" }
 parking_lot = "0.11"
 smallvec = { version = "1.6.1", features = ["union", "may_dangle"] }
 
diff --git a/compiler/rustc_symbol_mangling/Cargo.toml b/compiler/rustc_symbol_mangling/Cargo.toml
index b9751f0adb517..d5befa10e2363 100644
--- a/compiler/rustc_symbol_mangling/Cargo.toml
+++ b/compiler/rustc_symbol_mangling/Cargo.toml
@@ -16,5 +16,4 @@ rustc_middle = { path = "../rustc_middle" }
 rustc_hir = { path = "../rustc_hir" }
 rustc_target = { path = "../rustc_target" }
 rustc_data_structures = { path = "../rustc_data_structures" }
-rustc_query_system = { path = "../rustc_query_system" }
 rustc_session = { path = "../rustc_session" }