Expose .selector and .address only on external/public functions

crates/solidity/inputs/language/bindings/rules.msgb

@@ -895,21 +895,30 @@ inherit .lexical_scope
 ;;; Function types
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 
-@ftype [FunctionType] {
+@ftype [FunctionType @attrs [FunctionTypeAttributes]] {
+  ; Compute the built-in type of the function
+  ; %functionExternal provides access to .selector and .address
+  var type = "%function"
+  scan (source-text @attrs) {
+    "external" {
+      set type = "%functionExternal"
+    }
+  }
+
   node @ftype.lexical_scope
   node @ftype.output
 
   ; This path pushes the function type to the symbol stack
   ; TODO: add parameter and return types to distinguish between different function types
   node function_type
-  attr (function_type) push_symbol = "%function"
+  attr (function_type) push_symbol = type
 
   edge @ftype.output -> function_type
   edge function_type -> @ftype.lexical_scope
 
   ; the pop path for the using directive
   node pop_function_type
-  attr (pop_function_type) pop_symbol = "%function"
+  attr (pop_function_type) pop_symbol = type
 
   let @ftype.pop_begin = pop_function_type
   let @ftype.pop_end = pop_function_type
@@ -1036,7 +1045,14 @@ inherit .lexical_scope
   edge @params.defs -> @param.def
 }
 
-@function [FunctionDefinition] {
+@function [FunctionDefinition @attrs [FunctionAttributes]] {
+  var function_type = "%function"
+  scan (source-text @attrs) {
+    "\\b(public|external)\\b" {
+      set function_type = "%functionExternal"
+    }
+  }
+
   node @function.lexical_scope
   node @function.def
 
@@ -1045,7 +1061,7 @@ inherit .lexical_scope
   node typeof
   attr (typeof) push_symbol = "@typeof"
   node type_function
-  attr (type_function) push_symbol = "%function"
+  attr (type_function) push_symbol = function_type
   edge @function.def -> typeof
   edge typeof -> type_function
   edge type_function -> @function.lexical_scope

crates/solidity/inputs/language/src/definition.rs

@@ -6898,7 +6898,7 @@ codegen_language_macros::compile!(Language(
             enabled = From("0.6.2")
         ),
         BuiltInType(
-            name = "$function",
+            name = "$functionExternal",
             fields = [
                 BuiltInField(definition = "$address $address", enabled = From("0.8.2")),
                 BuiltInField(definition = "$selector selector", enabled = From("0.4.17"))

crates/solidity/testing/snapshots/bindings_output/function_types/externals/generated/0.4.11-failure.txt

@@ -0,0 +1,23 @@
+# This file is generated automatically by infrastructure scripts. Please don't edit by hand.
+
+References and definitions: 
+   ╭─[input.sol:1:1]
+   │
+ 1 │ contract Test {
+   │          ──┬─  
+   │            ╰─── def: 1
+ 2 │     function test() public {
+   │              ──┬─  
+   │                ╰─── def: 2
+ 3 │         function() external v1;
+   │                             ─┬  
+   │                              ╰── def: 3
+ 4 │         v1.selector;
+   │         ─┬ ────┬───  
+   │          ╰─────────── ref: 3
+   │                │     
+   │                ╰───── unresolved
+ 5 │         v1.address;
+   │         ─┬  
+   │          ╰── ref: 3
+───╯

crates/solidity/testing/snapshots/bindings_output/function_types/externals/generated/0.4.21-success.txt

@@ -0,0 +1,23 @@
+# This file is generated automatically by infrastructure scripts. Please don't edit by hand.
+
+References and definitions: 
+   ╭─[input.sol:1:1]
+   │
+ 1 │ contract Test {
+   │          ──┬─  
+   │            ╰─── def: 1
+ 2 │     function test() public {
+   │              ──┬─  
+   │                ╰─── def: 2
+ 3 │         function() external v1;
+   │                             ─┬  
+   │                              ╰── def: 3
+ 4 │         v1.selector;
+   │         ─┬ ────┬───  
+   │          ╰─────────── ref: 3
+   │                │     
+   │                ╰───── ref: built-in
+ 5 │         v1.address;
+   │         ─┬  
+   │          ╰── ref: 3
+───╯

crates/solidity/testing/snapshots/bindings_output/function_types/externals/input.sol

@@ -0,0 +1,7 @@
+contract Test {
+    function test() public {
+        function() external v1;
+        v1.selector;
+        v1.address;
+    }
+}