chore: improve some error messages (#3524)

fix array bounds check and `create_*` builtin error messages

- array bounds checks, previously were something like

`clamp lt [mload, 640 <result>]`

- codesize check error message was missing for create builtins
- create failure error message was also missing

vyper/builtins/functions.py

@@ -1634,7 +1634,9 @@ def _create_ir(value, buf, length, salt=None, checked=True):
     if not checked:
         return ret
 
-    return clamp_nonzero(ret)
+    ret = clamp_nonzero(ret)
+    ret.set_error_msg(f"{create_op} failed")
+    return ret
 
 
 # calculate the gas used by create for a given number of bytes
@@ -1830,7 +1832,10 @@ def _build_create_IR(self, expr, args, context, value, salt):
                 ir = ["seq"]
 
                 # make sure there is actually code at the target
-                ir.append(["assert", codesize])
+                check_codesize = ["assert", codesize]
+                ir.append(
+                    IRnode.from_list(check_codesize, error_msg="empty target (create_copy_of)")
+                )
 
                 # store the preamble at msize + 22 (zero padding)
                 preamble, preamble_len = _create_preamble(codesize)
@@ -1920,7 +1925,12 @@ def _build_create_IR(self, expr, args, context, value, salt, code_offset, raw_ar
                 # (code_ofst == (extcodesize target) would be empty
                 # initcode, which we disallow for hygiene reasons -
                 # same as `create_copy_of` on an empty target).
-                ir.append(["assert", ["sgt", codesize, 0]])
+                check_codesize = ["assert", ["sgt", codesize, 0]]
+                ir.append(
+                    IRnode.from_list(
+                        check_codesize, error_msg="empty target (create_from_blueprint)"
+                    )
+                )
 
                 # copy the target code into memory.
                 # layout starting from mem_ofst:

vyper/codegen/core.py

@@ -539,6 +539,7 @@ def _get_element_ptr_array(parent, key, array_bounds_check):
         # an array index, and the clamp will throw an error.
         # NOTE: there are optimization rules for this when ix or bound is literal
         ix = clamp("lt", ix, bound)
+        ix.set_error_msg(f"{parent.typ} bounds check")
 
     if parent.encoding == Encoding.ABI:
         if parent.location == STORAGE:

vyper/codegen/ir_node.py

@@ -330,6 +330,14 @@ def is_complex_ir(self):
             and self.value.lower() not in do_not_cache
         )
 
+    # set an error message and push down into all children.
+    # useful for overriding an error message generated by a helper
+    # function with a more specific error message.
+    def set_error_msg(self, error_msg: str) -> None:
+        self.error_msg = error_msg
+        for arg in self.args:
+            arg.set_error_msg(error_msg)
+
     # get the unique symbols contained in this node, which provides
     # sanity check invariants for the optimizer.
     # cache because it's a perf hotspot. note that this (and other cached