add tests for `@src`

test/compile_errors.zig

@@ -2,6 +2,14 @@ const tests = @import("tests.zig");
 const std = @import("std");
 
 pub fn addCases(cases: *tests.CompileErrorContext) void {
+    cases.add("@src outside function",
+        \\comptime {
+        \\    @src();
+        \\}
+    , &[_][]const u8{
+        "tmp.zig:2:5: error: @src outside function",
+    });
+
     cases.add("call assigned to constant",
         \\const Foo = struct {
         \\    x: i32,

test/stage1/behavior.zig

@@ -131,4 +131,5 @@ comptime {
     }
     _ = @import("behavior/while.zig");
     _ = @import("behavior/widening.zig");
+    _ = @import("behavior/src.zig");
 }

test/stage1/behavior/src.zig

@@ -0,0 +1,15 @@
+const std = @import("std");
+const expect = std.testing.expect;
+
+test "@src" {
+    doTheTest();
+}
+
+fn doTheTest() void {
+    const src = @src();
+
+    expect(src.line == 9);
+    expect(src.column == 17);
+    expect(std.mem.endsWith(u8, src.fn_name, "doTheTest"));
+    expect(std.mem.endsWith(u8, src.file, "src.zig"));
+}