Support #![crate_type = "proc-macro"]

Author: dtolnay

compiler/base/modify-cargo-toml/src/main.rs

@@ -114,14 +114,20 @@ fn set_crate_type(cargo_toml: Value, crate_type: &str) -> Value {
     #[derive(Debug, Default, Serialize, Deserialize)]
     #[serde(rename_all = "kebab-case")]
     struct Lib {
-        #[serde(default)]
+        #[serde(default, skip_serializing_if = "Vec::is_empty")]
         crate_type: Vec<String>,
+        #[serde(default)]
+        proc_macro: bool,
         #[serde(flatten)]
         other: Other,
     }
 
     modify(cargo_toml, |mut cargo_toml: CargoToml| {
-        ensure_string_in_vec(&mut cargo_toml.lib.crate_type, crate_type);
+        if crate_type == "proc-macro" {
+            cargo_toml.lib.proc_macro = true;
+        } else {
+            ensure_string_in_vec(&mut cargo_toml.lib.crate_type, crate_type);
+        }
         cargo_toml
     })
 }

tests/spec/features/automatic_primary_action_spec.rb

@@ -32,6 +32,33 @@
     end
   end
 
+  scenario "when the crate is a procedural macro" do
+    editor.set <<~EOF
+      #![crate_type = "proc-macro"]
+
+      use proc_macro::TokenStream;
+
+      /// Example:
+      /// ```
+      /// playground::demo!();
+      /// type T = aaa;
+      /// ```
+      #[proc_macro]
+      pub fn demo(_input: TokenStream) -> TokenStream {
+          eprintln!("wow wow");
+          "struct Aaa;".parse().unwrap()
+      }
+
+      /*
+      #[test]*/
+    EOF
+    click_on("Test")
+
+    within(:output, :stdout) do
+      expect(page).to have_content 'a struct with a similar name exists: `Aaa`'
+    end
+  end
+
   scenario "when the crate is a library with tests" do
     editor.set <<~EOF
       #![crate_type="lib"]

ui/frontend/selectors/index.ts

@@ -21,7 +21,7 @@ const autoPrimaryActionSelector = createSelector(
   hasTestsSelector,
   hasMainFunctionSelector,
   (crateType, hasTests, hasMainFunction) => {
-    if (crateType) {
+    if (crateType && crateType !== 'proc-macro') {
       if (crateType === 'bin') {
         return PrimaryActionCore.Execute;
       } else {
@@ -43,9 +43,19 @@ export const runAsTest = createSelector(
   autoPrimaryActionSelector,
   primaryAction => primaryAction === PrimaryActionCore.Test,
 );
+
 export const getCrateType = createSelector(
+  crateTypeSelector,
   autoPrimaryActionSelector,
-  primaryAction => primaryAction === PrimaryActionCore.Execute ? 'bin' : 'lib',
+  (crateType, primaryAction) => {
+    if (crateType) {
+      return crateType;
+    } else if (primaryAction === PrimaryActionCore.Execute) {
+      return 'bin';
+    } else {
+      return 'lib';
+    }
+  },
 );
 
 const rawPrimaryActionSelector = (state: State) => state.configuration.primaryAction;