Fix @adapt_structure for modules that only import the macro.

Project.toml

@@ -1,6 +1,6 @@
 name = "Adapt"
 uuid = "79e6a3ab-5dfb-504d-930d-738a2a938a0e"
-version = "4.5.1"
+version = "4.5.2"
 
 [deps]
 LinearAlgebra = "37e2e46d-f89d-539d-b4ee-838fcccc9c8e"

src/macro.jl

@@ -5,10 +5,10 @@ Define a method `adapt_structure(to, obj::T)` which calls `adapt_structure` on e
 of `obj` and constructs a new instance of `T` using the default constuctor `T(...)`.
 """
 macro adapt_structure(T)
-    esc(quote
-        @generated function Adapt.adapt_structure(to, obj::$T)
-            assignments = Any[:(Adapt.adapt_structure(to, obj.$name)) for name in fieldnames(obj)]
-            return Expr(:call, $T, assignments...)
+    quote
+        @generated function $Adapt.adapt_structure($(esc(:to)), $(esc(:obj))::$(esc(T)))
+            assignments = Any[:($$Adapt.adapt_structure(to, obj.$name)) for name in fieldnames($(esc(:obj)))]
+            return Expr(:call, $(esc(T)), assignments...)
         end
-    end)
+    end
 end

test/runtests.jl

@@ -221,6 +221,17 @@ end
     end
     Adapt.@adapt_structure LocalStruct
     @test adapt(CustomArray, LocalStruct(1)) === LocalStruct(1)
+
+    # The macro must work in modules that only import @adapt_structure,
+    # not the Adapt module itself (e.g. `using Adapt: @adapt_structure`).
+    @eval module ModuleOnlyImportingMacro
+        using Adapt: @adapt_structure
+        struct S
+            x::Int
+        end
+        @adapt_structure S
+    end
+    @test adapt(CustomArray, ModuleOnlyImportingMacro.S(1)) === ModuleOnlyImportingMacro.S(1)
 end