Print nicer "defined in" for functions defined on stdin/via source

This would tell you a function was "Defined in - @ line 1" for every
function defined via `source`.

Really, ideally we'd figure out where the *source* call was, but that'
much more complicated, so we just give a comprehensible message.

src/builtin_functions.cpp

@@ -152,16 +152,23 @@ static int report_function_metadata(const wchar_t *funcname, bool verbose, io_st
     }
 
     if (metadata_as_comments) {
-        if (std::wcscmp(path, L"stdin") != 0) {
-            wcstring comment;
+        // "stdin" means it was defined interactively, "-" means it was defined via `source`.
+        // Neither is useful information.
+        wcstring comment;
+        if (!std::wcscmp(path, L"stdin")) {
+            append_format(comment, L"# Defined interactively\n");
+        } else if (!std::wcscmp(path, L"-")) {
+            append_format(comment, L"# Defined via `source`\n");
+        } else {
             append_format(comment, L"# Defined in %ls @ line %d\n", path, line_number);
-            if (!streams.out_is_redirected && isatty(STDOUT_FILENO)) {
-                std::vector<highlight_spec_t> colors;
-                highlight_shell(comment, colors, parser.context());
-                streams.out.append(str2wcstring(colorize(comment, colors, parser.vars())));
-            } else {
-                streams.out.append(comment);
-            }
+        }
+
+        if (!streams.out_is_redirected && isatty(STDOUT_FILENO)) {
+            std::vector<highlight_spec_t> colors;
+            highlight_shell(comment, colors, parser.context());
+            streams.out.append(str2wcstring(colorize(comment, colors, parser.vars())));
+        } else {
+            streams.out.append(comment);
         }
     } else {
         streams.out.append_format(L"%ls\n", path);

src/builtin_type.cpp

@@ -147,7 +147,15 @@ maybe_t<int> builtin_type(parser_t &parser, io_streams_t &streams, wchar_t **arg
                     if (path) {
                         int line_number = function_get_definition_lineno(name);
                         wcstring comment;
-                        append_format(comment, L"# Defined in %ls @ line %d\n", path, line_number);
+                        if (std::wcscmp(path, L"-") != 0) {
+                            append_format(comment, L"# Defined in %ls @ line %d\n", path, line_number);
+                        } else {
+                            append_format(comment, L"# Defined via `source`\n");
+                        }
+                        def = comment.append(def);
+                    } else {
+                        wcstring comment;
+                        append_format(comment, L"# Defined interactively");
                         def = comment.append(def);
                     }
                     if (!streams.out_is_redirected && isatty(STDOUT_FILENO)) {

tests/checks/alias.fish

@@ -27,7 +27,7 @@ alias l. "ls -d .*"
 
 alias d "'/mnt/c/Program Files (x86)/devenv.exe' /Edit"
 functions d
-# CHECK: # Defined in - @ line 1
+# CHECK: # Defined via `source`
 # CHECK: function d --wraps=\'/mnt/c/Program\ Files\ \(x86\)/devenv.exe\'\ /Edit --description alias\ d\ \'/mnt/c/Program\ Files\ \(x86\)/devenv.exe\'\ /Edit
 # CHECK: '/mnt/c/Program Files (x86)/devenv.exe' /Edit $argv;
 # CHECK: end
@@ -35,7 +35,7 @@ functions d
 # Use "command" to prevent recusion, and don't add --wraps to avoid accidental recursion in completion.
 alias e 'e --option=value'
 functions e
-# CHECK: # Defined in - @ line 1
+# CHECK: # Defined via `source`
 # CHECK: function e --description 'alias e e --option=value'
 # CHECK: command e --option=value $argv;
 # CHECK: end
@@ -43,7 +43,7 @@ functions e
 # Don't add --wraps if it looks like a wrapper command to avoid accidental recursion in completion.
 alias f 'wrapper around f'
 functions f
-# CHECK: # Defined in - @ line 1
+# CHECK: # Defined via `source`
 # CHECK: function f --description 'alias f wrapper around f'
 # CHECK: wrapper around f $argv;
 # CHECK: end

tests/checks/function.fish

@@ -100,9 +100,9 @@ set -l name1a (functions name1a)
 set -l name3 (functions name3)
 set -l name3a (functions name3a)
 # First line for the non-copied function is "# Defined in checks/function.fish" - skip it to work around #6575.
-test "$name1[3..-1]" = "$name1a[2..-1]"; and echo "1 = 1a"
+test "$name1[3..-1]" = "$name1a[3..-1]"; and echo "1 = 1a"
 #CHECK: 1 = 1a
-test "$name3[3..-1]" = "$name3a[2..-1]"; and echo "3 = 3a"
+test "$name3[3..-1]" = "$name3a[3..-1]"; and echo "3 = 3a"
 #CHECK: 3 = 3a
 
 function test

tests/checks/functions.fish

@@ -91,3 +91,11 @@ functions f1 test_func_desc
 functions --erase ls
 type -t ls
 #CHECK: file
+
+echo "function t; echo tttt; end" | source
+functions t
+# CHECK: # Defined via `source`
+# CHECK: function t
+# CHECK: echo tttt;
+# CHECK: end
+