From 5fa22df4281d984b005d076f29a58ae35ac7854e Mon Sep 17 00:00:00 2001
From: Eric Hanson <5846501+ericphanson@users.noreply.github.com>
Date: Sun, 11 Jan 2026 13:05:37 +0100
Subject: [PATCH 1/2] add test for issue 79

---
 Project.toml                            |  1 +
 test/Issue79Pkg/Project.toml            | 10 ++++++++++
 test/Issue79Pkg/ext/LinearAlgebraExt.jl |  6 ++++++
 test/Issue79Pkg/ext/SubmoduleExt.jl     |  7 +++++++
 test/Issue79Pkg/src/Issue79Pkg.jl       |  3 +++
 test/issue_79_test.jl                   | 10 ++++++++++
 test/runtests.jl                        |  5 +++++
 7 files changed, 42 insertions(+)
 create mode 100644 test/Issue79Pkg/Project.toml
 create mode 100644 test/Issue79Pkg/ext/LinearAlgebraExt.jl
 create mode 100644 test/Issue79Pkg/ext/SubmoduleExt.jl
 create mode 100644 test/Issue79Pkg/src/Issue79Pkg.jl
 create mode 100644 test/issue_79_test.jl

diff --git a/Project.toml b/Project.toml
index f4008828..ea80bec2 100644
--- a/Project.toml
+++ b/Project.toml
@@ -4,6 +4,7 @@ version = "1.14.1"
 authors = ["Eric P. Hanson"]
 
 [deps]
+Issue79Pkg = "fa155e15-ec49-4eec-b540-f513de9043b2"
 Markdown = "d6f4376e-aef5-505a-96c1-9c027394607a"
 Pkg = "44cfe95a-1eb2-52ea-b672-e2afdf69b78f"
 PrecompileTools = "aea7be01-6a6a-4083-8856-8a6e6704d82a"
diff --git a/test/Issue79Pkg/Project.toml b/test/Issue79Pkg/Project.toml
new file mode 100644
index 00000000..dc99e6b3
--- /dev/null
+++ b/test/Issue79Pkg/Project.toml
@@ -0,0 +1,10 @@
+name = "Issue79Pkg"
+uuid = "fa155e15-ec49-4eec-b540-f513de9043b2"
+authors = ["ExplicitImports tests"]
+version = "0.1.0"
+
+[weakdeps]
+LinearAlgebra = "37e2e46d-f89d-539d-b4ee-838fcccc9c8e"
+
+[extensions]
+LinearAlgebraExt = "LinearAlgebra"
diff --git a/test/Issue79Pkg/ext/LinearAlgebraExt.jl b/test/Issue79Pkg/ext/LinearAlgebraExt.jl
new file mode 100644
index 00000000..52bcaaa1
--- /dev/null
+++ b/test/Issue79Pkg/ext/LinearAlgebraExt.jl
@@ -0,0 +1,6 @@
+module LinearAlgebraExt
+
+include("SubmoduleExt.jl")
+using .SubmoduleExt
+
+end # module LinearAlgebraExt
diff --git a/test/Issue79Pkg/ext/SubmoduleExt.jl b/test/Issue79Pkg/ext/SubmoduleExt.jl
new file mode 100644
index 00000000..bf9af91f
--- /dev/null
+++ b/test/Issue79Pkg/ext/SubmoduleExt.jl
@@ -0,0 +1,7 @@
+module SubmoduleExt
+
+export LOCAL_CONST
+
+const LOCAL_CONST = 1
+
+end # module SubmoduleExt
diff --git a/test/Issue79Pkg/src/Issue79Pkg.jl b/test/Issue79Pkg/src/Issue79Pkg.jl
new file mode 100644
index 00000000..e291d3d8
--- /dev/null
+++ b/test/Issue79Pkg/src/Issue79Pkg.jl
@@ -0,0 +1,3 @@
+module Issue79Pkg
+
+end # module Issue79Pkg
diff --git a/test/issue_79_test.jl b/test/issue_79_test.jl
new file mode 100644
index 00000000..11c70bbd
--- /dev/null
+++ b/test/issue_79_test.jl
@@ -0,0 +1,10 @@
+using Issue79Pkg
+using LinearAlgebra
+
+ext_mod = Base.get_extension(Issue79Pkg, :LinearAlgebraExt)
+
+@testset "extension submodule analyzable (#79)" begin
+    @test ext_mod !== nothing
+    @test isdefined(ext_mod, :SubmoduleExt)
+    @test check_no_implicit_imports(Issue79Pkg) === nothing
+end
diff --git a/test/runtests.jl b/test/runtests.jl
index 5d1a14d1..d4735855 100644
--- a/test/runtests.jl
+++ b/test/runtests.jl
@@ -1,5 +1,6 @@
 using Pkg
 Pkg.develop(; path=joinpath(@__DIR__, "TestPkg"))
+Pkg.develop(; path=joinpath(@__DIR__, "Issue79Pkg"))
 Pkg.precompile()
 using ExplicitImports
 using ExplicitImports: analyze_all_names, has_ancestor, should_skip,
@@ -105,6 +106,10 @@ include("issue_140.jl")
                                 (; name=:groupby, source=DataFrames.DataAPI)]
     end
 
+    @testset "Extension submodules (#79)" begin
+        include("issue_79_test.jl")
+    end
+
     @testset "Field names shadowing external globals (#111)" begin
         include("issue_111_test.jl")
     end

From ebb91131d26908702c6abab16d88c1e05576fa3a Mon Sep 17 00:00:00 2001
From: Eric Hanson <5846501+ericphanson@users.noreply.github.com>
Date: Sun, 11 Jan 2026 14:02:55 +0100
Subject: [PATCH 2/2] Update Project.toml

---
 Project.toml | 1 -
 1 file changed, 1 deletion(-)

diff --git a/Project.toml b/Project.toml
index ea80bec2..f4008828 100644
--- a/Project.toml
+++ b/Project.toml
@@ -4,7 +4,6 @@ version = "1.14.1"
 authors = ["Eric P. Hanson"]
 
 [deps]
-Issue79Pkg = "fa155e15-ec49-4eec-b540-f513de9043b2"
 Markdown = "d6f4376e-aef5-505a-96c1-9c027394607a"
 Pkg = "44cfe95a-1eb2-52ea-b672-e2afdf69b78f"
 PrecompileTools = "aea7be01-6a6a-4083-8856-8a6e6704d82a"