Added error tests for un-equal types in do loop

tests/errors/loop_01.py

@@ -0,0 +1,8 @@
+from ltypes import i16
+
+def test_increment():
+    i: i16
+    for i in range(15, i16(-1), i16(-1)):
+        print(i)
+
+test_increment()

tests/errors/loop_02.py

@@ -0,0 +1,8 @@
+from ltypes import i16
+
+def test_increment():
+    i: i16
+    for i in range(i16(15), i16(-1), -1):
+        print(i)
+
+test_increment()

tests/reference/asr-loop_01-e7aa06a.json

@@ -0,0 +1,13 @@
+{
+    "basename": "asr-loop_01-e7aa06a",
+    "cmd": "lpython --show-asr --no-color {infile} -o {outfile}",
+    "infile": "tests/errors/loop_01.py",
+    "infile_hash": "dfe89b806a2b527a01526e9e55edc1271783e1ab916245222b561dee",
+    "outfile": null,
+    "outfile_hash": null,
+    "stdout": null,
+    "stdout_hash": null,
+    "stderr": "asr-loop_01-e7aa06a.stderr",
+    "stderr_hash": "256fe74af3480ca97b87c1b6f770cee10753e5f097d5a2d79135e736",
+    "returncode": 2
+}

tests/reference/asr-loop_01-e7aa06a.stderr

@@ -0,0 +1,5 @@
+semantic error: Type mismatch in loop start and loop end values, the types must be compatible
+ --> tests/errors/loop_01.py:5:20
+  |
+5 |     for i in range(15, i16(-1), i16(-1)):
+  |                    ^^  ^^^^^^^ type mismatch ('i32' and 'i16')

tests/reference/asr-loop_02-5741651.json

@@ -0,0 +1,13 @@
+{
+    "basename": "asr-loop_02-5741651",
+    "cmd": "lpython --show-asr --no-color {infile} -o {outfile}",
+    "infile": "tests/errors/loop_02.py",
+    "infile_hash": "e88f2cac76a9de67c851a22a64cdae4553321d80ae64f5720a424a15",
+    "outfile": null,
+    "outfile_hash": null,
+    "stdout": null,
+    "stdout_hash": null,
+    "stderr": "asr-loop_02-5741651.stderr",
+    "stderr_hash": "a8262496250102a77a9e5718d40aaf1067fb21a18fb047885aa643ac",
+    "returncode": 2
+}

tests/reference/asr-loop_02-5741651.stderr

@@ -0,0 +1,5 @@
+semantic error: Type mismatch in loop start and increment values, the types must be compatible
+ --> tests/errors/loop_02.py:5:20
+  |
+5 |     for i in range(i16(15), i16(-1), -1):
+  |                    ^^^^^^^           ^^ type mismatch ('i16' and 'i32')

tests/tests.toml

@@ -950,6 +950,14 @@ asr = true
 filename = "errors/enum_02.py"
 asr = true
 
+[[test]]
+filename = "errors/loop_01.py"
+asr = true
+
+[[test]]
+filename = "errors/loop_02.py"
+asr = true
+
 [[test]]
 filename = "errors/test_goto.py"
 asr = true