feat: error message for unknown global variables

src/compile.zig

@@ -53,6 +53,7 @@ pub const Compilation = struct {
             try w.splatByteAll(' ', column - 1);
         }
         try w.writeAll("^\n");
+        return w.flush();
     }
 
     pub const CompileOptions = struct {
@@ -78,7 +79,10 @@ pub const Compilation = struct {
 
         var sema: Sema = .{
             .gpa = gpa,
-            .ir = &ir,
+            .arena = arena,
+            .tree = ast,
+            .ir = ir,
+            .errors = &errors,
         };
         defer sema.deinit();
 
@@ -119,7 +123,12 @@ pub const Compilation = struct {
             }
             break :fatal true;
         } else fatal: {
-            try sema.analyzeFile(.file_inst);
+            sema.analyzeFile(.file_inst) catch |err| switch (err) {
+                error.OutOfMemory => return error.OutOfMemory,
+                error.AnalysisFail => break :fatal true,
+                // TODO: These errors should be handled...
+                else => |e| return e,
+            };
             break :fatal false;
         };
         return .{
@@ -195,13 +204,13 @@ pub const Compilation = struct {
     }
 };
 
-const Loc = struct {
+pub const Loc = struct {
     line: usize,
     column: usize,
     source_line: []const u8,
 };
 
-fn findLineColumn(source: []const u8, byte_offset: usize) Loc {
+pub fn findLineColumn(source: []const u8, byte_offset: usize) Loc {
     var line: usize = 0;
     var column: usize = 0;
     var line_start: usize = 0;