analysis: add contextual checks for Assign expr

src/analysis.zig

@@ -329,8 +329,8 @@ pub const TypeSolver = struct {
                     },
 
                     else => {
-                        std.debug.warn(
-                            "Expected Struct/Enum as get target, got {}\n",
+                        self.doError(
+                            "Expected Struct/Enum as get target, got {}",
                             comp.SymbolUnderlyingTypeEnum(global_typ),
                         );
 
@@ -340,12 +340,22 @@ pub const TypeSolver = struct {
             },
 
             .Assign => |assign| {
+                if (ctx.current_scope == null) {
+                    self.doError("Can't assign without a scope");
+                    return CompileError.Invalid;
+                }
+
                 var var_type = ctx.current_scope.?.env.get(
                     assign.name.lexeme,
-                ).?.value;
+                );
+
+                if (var_type == null) {
+                    self.doError("Assign target variable not found");
+                    return CompileError.Invalid;
+                }
 
                 var value_type = try self.resolveExprType(ctx, assign.value);
-                try self.expectSymUnTypeEqual(var_type, value_type);
+                try self.expectSymUnTypeEqual(var_type.?.value, value_type);
                 return var_type;
             },
 

src/codegen.zig

@@ -13,6 +13,7 @@ pub const CompileError = error{
     LLVMError,
     EmitError,
     TypeError,
+    Invalid,
 };
 
 fn mkLLVMBool(val: bool) llvm.LLVMValueRef {