4 files changed, 30 insertions, 22 deletions
diff --git a/std/encoding/base32_test.ts b/std/encoding/base32_test.ts
index eb51e44ab..28550d57a 100644
--- a/std/encoding/base32_test.ts
+++ b/std/encoding/base32_test.ts
@@ -6,7 +6,7 @@ import { encode, decode } from "./base32.ts";
 
 // Lifted from https://stackoverflow.com/questions/38987784
 const fromHexString = (hexString: string): Uint8Array =>
-  new Uint8Array(hexString.match(/.{1,2}/g).map(byte => parseInt(byte, 16)));
+  new Uint8Array(hexString.match(/.{1,2}/g)!.map(byte => parseInt(byte, 16)));
 const toHexString = (bytes: Uint8Array): string =>
   bytes.reduce((str, byte) => str + byte.toString(16).padStart(2, "0"), "");
 
diff --git a/std/encoding/csv.ts b/std/encoding/csv.ts
index 1314afcaa..12336b10d 100644
--- a/std/encoding/csv.ts
+++ b/std/encoding/csv.ts
@@ -46,7 +46,7 @@ function chkOptions(opt: ReadOptions): void {
   }
   if (
     INVALID_RUNE.includes(opt.comma) ||
-    INVALID_RUNE.includes(opt.comment) ||
+    (typeof opt.comment === "string" && INVALID_RUNE.includes(opt.comment)) ||
     opt.comma === opt.comment
   ) {
     throw new Error("Invalid Delimiter");
@@ -122,7 +122,7 @@ export async function readMatrix(
   }
 ): Promise<string[][]> {
   const result: string[][] = [];
-  let _nbFields: number;
+  let _nbFields: number | undefined;
   let lineResult: string[];
   let first = true;
   let lineIndex = 0;
@@ -253,8 +253,10 @@ export async function parse(
     });
   }
   if (opt.parse) {
-    assert(opt.parse != null, "opt.parse must be set");
-    return r.map((e: string[]): unknown => opt.parse(e));
+    return r.map((e: string[]): unknown => {
+      assert(opt.parse, "opt.parse must be set");
+      return opt.parse(e);
+    });
   }
   return r;
 }
diff --git a/std/encoding/csv_test.ts b/std/encoding/csv_test.ts
index 74ba8face..efea353e1 100644
--- a/std/encoding/csv_test.ts
+++ b/std/encoding/csv_test.ts
@@ -476,26 +476,32 @@ for (const t of testCases) {
       if (t.Error) {
         let err;
         try {
-          actual = await readMatrix(new BufReader(new StringReader(t.Input)), {
-            comma: comma,
-            comment: comment,
-            trimLeadingSpace: trim,
-            fieldsPerRecord: fieldsPerRec,
-            lazyQuotes: lazyquote
-          });
+          actual = await readMatrix(
+            new BufReader(new StringReader(t.Input ?? "")),
+            {
+              comma: comma,
+              comment: comment,
+              trimLeadingSpace: trim,
+              fieldsPerRecord: fieldsPerRec,
+              lazyQuotes: lazyquote
+            }
+          );
         } catch (e) {
           err = e;
         }
         assert(err);
         assertEquals(err.message, t.Error);
       } else {
-        actual = await readMatrix(new BufReader(new StringReader(t.Input)), {
-          comma: comma,
-          comment: comment,
-          trimLeadingSpace: trim,
-          fieldsPerRecord: fieldsPerRec,
-          lazyQuotes: lazyquote
-        });
+        actual = await readMatrix(
+          new BufReader(new StringReader(t.Input ?? "")),
+          {
+            comma: comma,
+            comment: comment,
+            trimLeadingSpace: trim,
+            fieldsPerRecord: fieldsPerRec,
+            lazyQuotes: lazyquote
+          }
+        );
         const expected = t.Output;
         assertEquals(actual, expected);
       }
diff --git a/std/encoding/yaml/loader/loader.ts b/std/encoding/yaml/loader/loader.ts
index 556bd5b47..7db72a01d 100644
--- a/std/encoding/yaml/loader/loader.ts
+++ b/std/encoding/yaml/loader/loader.ts
@@ -187,7 +187,7 @@ interface DirectiveHandlers {
   [directive: string]: (
     state: LoaderState,
     name: string,
-    ...args: unknown[]
+    ...args: string[]
   ) => void;
 }
 
@@ -362,7 +362,7 @@ function storeMappingPair(
         mergeMappings(state, result, valueNode[index], overridableKeys);
       }
     } else {
-      mergeMappings(state, result, valueNode, overridableKeys);
+      mergeMappings(state, result, valueNode as ArrayObject, overridableKeys);
     }
   } else {
     if (
@@ -1610,7 +1610,7 @@ function readDocument(state: LoaderState): void {
   const documentStart = state.position;
   let position: number,
     directiveName: string,
-    directiveArgs: unknown[],
+    directiveArgs: string[],
     hasDirectives = false,
     ch: number;