From e427498b00db6bf360f7d82a710ce83e880bf2e7 Mon Sep 17 00:00:00 2001
From: Eric Hanson <5846501+ericphanson@users.noreply.github.com>
Date: Thu, 31 Jul 2025 13:44:21 +0200
Subject: [PATCH 1/2] support old-style macros

---
 src/macro_expansion.jl | 12 ++++++++++--
 test/macros.jl         |  6 ++++++
 2 files changed, 16 insertions(+), 2 deletions(-)

diff --git a/src/macro_expansion.jl b/src/macro_expansion.jl
index 1e4ac756..acd7e710 100644
--- a/src/macro_expansion.jl
+++ b/src/macro_expansion.jl
@@ -145,8 +145,16 @@ function expand_macro(ctx, ex)
     end
     macro_invocation_world = Base.get_world_counter()
     expanded = try
-        # TODO: Allow invoking old-style macros for compat
-        invokelatest(macfunc, macro_args...)
+        if applicable(macfunc, macro_args...)
+            invokelatest(macfunc, macro_args...)
+        else
+            # try old-style macro
+            args = [Expr(x) for x in macro_args[2:end]]
+            line, _ = source_location(macname)
+            file = filename(macname)
+            line_number_node = Base.LineNumberNode(line, file)
+            invokelatest(macfunc, line_number_node, ctx.current_layer.mod, args...)
+        end
     catch exc
         if exc isa MacroExpansionError
             # Add context to the error.
diff --git a/test/macros.jl b/test/macros.jl
index 6e25c326..21aacc81 100644
--- a/test/macros.jl
+++ b/test/macros.jl
@@ -142,4 +142,10 @@ end == [
     "2"
 ]
 
+# old-style generated macro, e.g. as lowered by pre-JuliaLowering lowering
+@eval test_mod var"@hi"(__source__::LineNumberNode, __module__::Module) = "hi"
+
+# check that we can macroexpand it properly even though we don't have the new method
+# that accepts a MacroExpansionContext
+@test JuliaLowering.include_string(test_mod, "@hi") == "hi"
 end

From 67b12f08c4e3ba74f3c5f20c9be96644e17265bf Mon Sep 17 00:00:00 2001
From: Eric Hanson <5846501+ericphanson@users.noreply.github.com>
Date: Thu, 31 Jul 2025 14:16:14 +0200
Subject: [PATCH 2/2] Update src/macro_expansion.jl

---
 src/macro_expansion.jl | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/macro_expansion.jl b/src/macro_expansion.jl
index acd7e710..91c92f22 100644
--- a/src/macro_expansion.jl
+++ b/src/macro_expansion.jl
@@ -149,7 +149,7 @@ function expand_macro(ctx, ex)
             invokelatest(macfunc, macro_args...)
         else
             # try old-style macro
-            args = [Expr(x) for x in macro_args[2:end]]
+            args = (Expr(x) for x in macro_args[2:end])
             line, _ = source_location(macname)
             file = filename(macname)
             line_number_node = Base.LineNumberNode(line, file)