From 548a7d372477de0188035b67623b3e38e0bdafb7 Mon Sep 17 00:00:00 2001
From: Eric Hanson <5846501+ericphanson@users.noreply.github.com>
Date: Fri, 26 Apr 2024 01:24:55 +0200
Subject: [PATCH] handle unary `::` (#39)

* add failing test case

* fix test case

* format

* format

* also fix #36

* add failing test

* handle for loop arguments and nested local scope

* add some more nested scope tests

* handle unary `::`
---
 src/get_names_used.jl | 17 +++++++++++++----
 test/runtests.jl      |  6 ++++++
 test/test_mods.jl     | 18 +++++++++++++-----
 3 files changed, 32 insertions(+), 9 deletions(-)

diff --git a/src/get_names_used.jl b/src/get_names_used.jl
index 1e8494b..9b2f788 100644
--- a/src/get_names_used.jl
+++ b/src/get_names_used.jl
@@ -60,7 +60,7 @@ function is_anonymous_function_definition_arg(leaf)
         return child_index(get_parent(leaf, 3)) == 2
     elseif parents_match(leaf, (K"::",))
         # we must be on the LHS, otherwise we're a type
-        child_index(leaf) == 1 || return false
+        is_hastype_LHS(leaf) || return false
         # Ok, let's just step up one level and see again
         return is_anonymous_function_definition_arg(parent(leaf))
     elseif parents_match(leaf, (K"=",))
@@ -92,10 +92,10 @@ function is_struct_field_name(leaf)
     kind(leaf) == K"Identifier" || return false
     if parents_match(leaf, (K"::", K"block", K"struct"))
         # we want to be on the LHS of the `::`
-        return child_index(leaf) == 1
+        return is_hastype_LHS(leaf)
     elseif parents_match(leaf, (K"::", K"=", K"block", K"struct"))
         # if we are in a `Base.@kwdef`, we may be on the LHS of an `=`
-        return child_index(leaf) == 1 && child_index(parent(leaf)) == 1
+        return is_hastype_LHS(leaf) && child_index(parent(leaf)) == 1
     else
         return false
     end
@@ -149,7 +149,7 @@ function is_non_anonymous_function_definition_arg(leaf)
         return is_non_anonymous_function_definition_arg(parent(leaf))
     elseif parents_match(leaf, (K"::",))
         # we must be on the LHS, otherwise we're a type
-        child_index(leaf) == 1 || return false
+        is_hastype_LHS(leaf) || return false
         # Ok, let's just step up one level and see again
         return is_non_anonymous_function_definition_arg(parent(leaf))
     else
@@ -157,6 +157,15 @@ function is_non_anonymous_function_definition_arg(leaf)
     end
 end
 
+# matches `x` in `x::Y`, but not `Y`, nor `foo(::Y)`
+function is_hastype_LHS(leaf)
+    parents_match(leaf, (K"::",)) || return false
+    unary = has_flags(get_parent(leaf), JuliaSyntax.PREFIX_OP_FLAG)
+    unary && return false
+    # OK if not unary, then check we're in position 1 for LHS
+    return child_index(leaf) == 1
+end
+
 # Here we use the magic of AbstractTrees' `TreeCursor` so we can start at
 # a leaf and follow the parents up to see what scopes our leaf is in.
 # TODO- cleanup with parsing utilities (?)
diff --git a/test/runtests.jl b/test/runtests.jl
index affcae4..e7c1817 100644
--- a/test/runtests.jl
+++ b/test/runtests.jl
@@ -109,6 +109,12 @@ end
           ["using LinearAlgebra: LinearAlgebra"]
 end
 
+@testset "types without values in function signatures" begin
+    # https://github.com/ericphanson/ExplicitImports.jl/issues/33
+    @test using_statement.(explicit_imports_nonrecursive(TestMod8, "test_mods.jl")) ==
+          ["using LinearAlgebra: LinearAlgebra", "using LinearAlgebra: QR"]
+end
+
 @testset "scripts" begin
     str = sprint(print_explicit_imports_script, "script.jl")
     @test contains(str, "Script `script.jl`")
diff --git a/test/test_mods.jl b/test/test_mods.jl
index 4d75c35..59db70f 100644
--- a/test/test_mods.jl
+++ b/test/test_mods.jl
@@ -80,15 +80,23 @@ using LinearAlgebra
 # these are all local references to `I`, but you have to go up a scope to know that
 function foo(I)
     let
-        I+1
+        I + 1
     end
-    let k=I
-        k+I
+    let k = I
+        k + I
     end
     function bar(x)
-        I+1
+        return I + 1
     end
-    bar(I)
+    return bar(I)
 end
 
 end # TestMod7
+
+module TestMod8
+using LinearAlgebra
+
+# https://github.com/ericphanson/ExplicitImports.jl/issues/33
+foo(::QR) = ()
+
+end # TestMod8