diff --git a/toml/_parser.ts b/toml/_parser.ts
index 0107258f82f7..1981001bdd43 100644
--- a/toml/_parser.ts
+++ b/toml/_parser.ts
@@ -894,7 +894,7 @@ export function ParserFactory<T>(parser: ParserComponent<T>) {
           if (count > line.length) {
             count -= line.length + 1;
           } else {
-            return count;
+            break;
           }
         }
         return count;
diff --git a/toml/parse_test.ts b/toml/parse_test.ts
index 8fd88d1b1100..2e69caa80f2f 100644
--- a/toml/parse_test.ts
+++ b/toml/parse_test.ts
@@ -112,6 +112,14 @@ Violets are\\tblue"""`),
       TOMLParseError,
       "Invalid escape sequence: \\?",
     );
+    assertThrows(
+      () =>
+        parse(`"""
+Roses are red
+Violets are\\tblue`),
+      TOMLParseError,
+      "not closed",
+    );
   },
 });
 
@@ -146,6 +154,14 @@ Roses are red
 Violets are\\tblue'''`),
       "Roses are red\nViolets are\\tblue",
     );
+    assertThrows(
+      () =>
+        parse(`'''
+Roses are red
+Violets are\\tblue`),
+      TOMLParseError,
+      "not closed",
+    );
   },
 });
 
@@ -252,6 +268,7 @@ Deno.test({
     assertEquals(parse("224_617.445_991_228"), 224_617.445_991_228);
     assertThrows(() => parse(""));
     assertThrows(() => parse("X"));
+    assertThrows(() => parse("e_+-"));
   },
 });
 
@@ -352,6 +369,7 @@ Deno.test({
       ]`),
       [1, 2],
     );
+    assertThrows(() => parse("[1, 2, 3"), TOMLParseError, "not closed");
   },
 });
 
@@ -426,6 +444,7 @@ Deno.test({
   fn() {
     const source = {
       foo: {},
+      bar: null,
     };
 
     Utils.deepAssignWithTable(
@@ -446,6 +465,7 @@ Deno.test({
             },
           ],
         },
+        bar: null,
       },
     );
     Utils.deepAssignWithTable(
@@ -469,8 +489,37 @@ Deno.test({
             },
           ],
         },
+        bar: null,
       },
     );
+
+    assertThrows(
+      () =>
+        Utils.deepAssignWithTable(
+          source,
+          {
+            type: "TableArray",
+            key: [],
+            value: { email: "sub@example.com" },
+          },
+        ),
+      Error,
+      "Unexpected key length",
+    );
+
+    assertThrows(
+      () =>
+        Utils.deepAssignWithTable(
+          source,
+          {
+            type: "TableArray",
+            key: ["bar", "items"],
+            value: { email: "mail@example.com" },
+          },
+        ),
+      Error,
+      "Unexpected assign",
+    );
   },
 });
 
@@ -480,12 +529,25 @@ Deno.test({
     assertThrows(
       () => parse("foo = 1\nbar ="),
       TOMLParseError,
-      "on line 2, column 5",
+      "line 2, column 5",
     );
     assertThrows(
       () => parse("foo = 1\nbar = 'foo\nbaz=1"),
       TOMLParseError,
       "line 2, column 10",
     );
+    assertThrows(
+      () => parse(""),
+      TOMLParseError,
+      "line 1, column 0",
+    );
+    assertThrows(
+      () =>
+        ParserFactory((_s) => {
+          throw "Custom parser";
+        })(""),
+      TOMLParseError,
+      "[non-error thrown]",
+    );
   },
 });
diff --git a/toml/test.ts b/toml/test.ts
index d910444029bf..2011910280c2 100644
--- a/toml/test.ts
+++ b/toml/test.ts
@@ -41,6 +41,7 @@ Deno.test({
         literal3: "\\n\\t is 'literal'\\\n",
         literal4: 'Here are fifteen quotation marks: """""""""""""""',
         literal5: "Here are fifteen apostrophes: '''''''''''''''",
+        literal6: "'That,' she said, 'is still pointless.'",
         withApostrophe: "What if it's not?",
         withSemicolon: `const message = 'hello world';`,
         withHexNumberLiteral:
@@ -522,7 +523,7 @@ Deno.test({
       emptyArray: [],
       mixedArray1: [1, { b: 2 }],
       mixedArray2: [{ b: 2 }, 1],
-      nestedArray1: [[{ b: 1 }]],
+      nestedArray1: [[{ b: 1, date: new Date("2022-05-13") }]],
       nestedArray2: [[[{ b: 1 }]]],
       nestedArray3: [[], [{ b: 1 }]],
       deepNested: {
@@ -534,7 +535,7 @@ Deno.test({
     const expected = `emptyArray = []
 mixedArray1 = [1,{b = 2}]
 mixedArray2 = [{b = 2},1]
-nestedArray1 = [[{b = 1}]]
+nestedArray1 = [[{b = 1,date = "2022-05-13T00:00:00.000"}]]
 nestedArray2 = [[[{b = 1}]]]
 nestedArray3 = [[],[{b = 1}]]
 
@@ -762,3 +763,19 @@ Deno.test({
     assertEquals(actual, expected);
   },
 });
+
+Deno.test({
+  name: "stringify() throws on invalid value",
+  fn() {
+    assertThrows(
+      () => stringify({ a: [[null]] }),
+      Error,
+      "should never reach",
+    );
+    assertThrows(
+      () => stringify({ a: [[undefined]] }),
+      Error,
+      "should never reach",
+    );
+  },
+});
diff --git a/toml/testdata/string.toml b/toml/testdata/string.toml
index d5d84afe4822..dec147320b78 100644
--- a/toml/testdata/string.toml
+++ b/toml/testdata/string.toml
@@ -48,6 +48,7 @@ literal3 = '''
 '''
 literal4 = '''Here are fifteen quotation marks: """""""""""""""'''
 literal5 = "Here are fifteen apostrophes: '''''''''''''''"
+literal6 = ''''That,' she said, 'is still pointless.''''
 
 withApostrophe = "What if it's not?"
 withSemicolon = "const message = 'hello world';"