diff --git a/.gitattributes b/.gitattributes
new file mode 100644
index 00000000..6aaf3007
--- /dev/null
+++ b/.gitattributes
@@ -0,0 +1,3 @@
+test/fixtures/scripts/needs-compile.js eol=crlf
+test/fixtures/scripts/needs-compile.compiled.js eol=crlf
+test/fixtures/scripts/needs-compile.compiled.js.map eol=crlf
\ No newline at end of file
diff --git a/.gitignore b/.gitignore
index 950be1d1..da8673f3 100644
--- a/.gitignore
+++ b/.gitignore
@@ -2,3 +2,4 @@
 coverage
 .nyc_output
 node_modules
+.idea
diff --git a/lib/source.js b/lib/source.js
index f592f52e..60569da2 100644
--- a/lib/source.js
+++ b/lib/source.js
@@ -56,7 +56,7 @@ module.exports = class CovSource {
     const start = originalPositionTryBoth(
       sourceMap,
       lines[0].line,
-      startCol - lines[0].startCol
+      Math.max(0, startCol - lines[0].startCol)
     )
     let end = originalEndPositionFor(
       sourceMap,
diff --git a/test/fixtures/scripts/needs-compile.compiled.js b/test/fixtures/scripts/needs-compile.compiled.js
new file mode 100644
index 00000000..680de596
--- /dev/null
+++ b/test/fixtures/scripts/needs-compile.compiled.js
@@ -0,0 +1,51 @@
+function _defineProperty(obj, key, value) { if (key in obj) { Object.defineProperty(obj, key, { value: value, enumerable: true, configurable: true, writable: true }); } else { obj[key] = value; } return obj; }
+
+function _classPrivateFieldGet(receiver, privateMap) { var descriptor = privateMap.get(receiver); if (!descriptor) { throw new TypeError("attempted to get private field on non-instance"); } if (descriptor.get) { return descriptor.get.call(receiver); } return descriptor.value; }
+
+// compile me with babel 7+:
+// > babel --plugins @babel/plugin-proposal-class-properties test/fixtures/scripts/needs-compile.js --out-file test/fixtures/scripts/needs-compile.compiled.js --source-maps
+// class uses private class fields - must be compiled
+// hello is called
+class Foo {
+  constructor() {
+    _defineProperty(this, "a", 1);
+
+    _b.set(this, {
+      writable: true,
+      value: 2
+    });
+
+    this.c = this.a + _classPrivateFieldGet(this, _b);
+  }
+
+  hello(i) {
+    console.info('hello:', this.c + i);
+  }
+
+} // class uses private class fields - must be compiled
+// hello is never called
+
+
+var _b = new WeakMap();
+
+class Bar {
+  constructor() {
+    _test.set(this, {
+      writable: true,
+      value: 99
+    });
+  }
+
+  hello() {
+    console.info(`Hello ${_classPrivateFieldGet(this, _test)}`);
+  }
+
+}
+
+var _test = new WeakMap();
+
+const foo = new Foo();
+foo.hello(1);
+const bar = new Bar();
+
+//# sourceMappingURL=needs-compile.compiled.js.map
\ No newline at end of file
diff --git a/test/fixtures/scripts/needs-compile.compiled.js.map b/test/fixtures/scripts/needs-compile.compiled.js.map
new file mode 100644
index 00000000..fd116497
--- /dev/null
+++ b/test/fixtures/scripts/needs-compile.compiled.js.map
@@ -0,0 +1 @@
+{"version":3,"sources":["needs-compile.js"],"names":[],"mappings":";;;;AAAA;AACA;AACA;AACA;AACA,MAAM,GAAN,CAAU;AAGR,EAAA,WAAW,GAAI;AAAA,+BAFX,CAEW;;AAAA;AAAA;AAAA,aADV;AACU;;AACb,SAAK,CAAL,GAAS,KAAK,CAAL,yBAAS,IAAT,KAAT;AACD;;AACD,EAAA,KAAK,CAAE,CAAF,EAAK;AACR,IAAA,OAAO,CAAC,IAAR,CAAa,QAAb,EAAuB,KAAK,CAAL,GAAS,CAAhC;AACD;;AARO,C,CAWV;AACA;;;;;AACA,MAAM,GAAN,CAAU;AAER,EAAA,WAAW,GAAI;AAAA;AAAA;AAAA,aADP;AACO;AACd;;AACD,EAAA,KAAK,GAAI;AACP,IAAA,OAAO,CAAC,IAAR,CAAc,SAAD,sBAAS,IAAT,QAAoB,EAAjC;AACD;;AANO;;;;AASV,MAAM,GAAG,GAAG,IAAI,GAAJ,EAAZ;AACA,GAAG,CAAC,KAAJ,CAAU,CAAV;AACA,MAAM,GAAG,GAAG,IAAI,GAAJ,EAAZ","file":"needs-compile.compiled.js","sourcesContent":["// compile me with babel 7+:\n// > babel --plugins @babel/plugin-proposal-class-properties test/fixtures/scripts/needs-compile.js --out-file test/fixtures/scripts/needs-compile.compiled.js --source-maps\n// class uses private class fields - must be compiled\n// hello is called\nclass Foo {\n  a = 1\n  #b = 2\n  constructor () {\n    this.c = this.a + this.#b;\n  }\n  hello (i) {\n    console.info('hello:', this.c + i)\n  }\n}\n\n// class uses private class fields - must be compiled\n// hello is never called\nclass Bar {\n  #test = 99\n  constructor () {\n  }\n  hello () {\n    console.info(`Hello ${this.#test}`)\n  }\n}\n\nconst foo = new Foo();\nfoo.hello(1)\nconst bar = new Bar()\n\n"]}
\ No newline at end of file
diff --git a/test/fixtures/scripts/needs-compile.js b/test/fixtures/scripts/needs-compile.js
new file mode 100644
index 00000000..149129ff
--- /dev/null
+++ b/test/fixtures/scripts/needs-compile.js
@@ -0,0 +1,32 @@
+// compile me with babel 7+:
+// > babel --plugins @babel/plugin-proposal-class-properties test/fixtures/scripts/needs-compile.js --out-file test/fixtures/scripts/needs-compile.compiled.js --source-maps
+// in addition, a .gitattribute clause forces this file and its compilation assets to crlf
+
+// class uses private class fields - must be compiled
+// hello is called
+class Foo {
+  a = 1
+  #b = 2
+  constructor () {
+    this.c = this.a + this.#b;
+  }
+  hello (i) {
+    console.info('hello:', this.c + i)
+  }
+}
+
+// class uses private class fields - must be compiled
+// hello is never called
+class Bar {
+  #test = 99
+  constructor () {
+  }
+  hello () {
+    console.info(`Hello ${this.#test}`)
+  }
+}
+
+const foo = new Foo();
+foo.hello(1)
+const bar = new Bar()
+
diff --git a/test/v8-to-istanbul.js b/test/v8-to-istanbul.js
index 10004967..bf17f13a 100644
--- a/test/v8-to-istanbul.js
+++ b/test/v8-to-istanbul.js
@@ -6,6 +6,7 @@ const V8ToIstanbul = require('../lib/v8-to-istanbul')
 const crypto = require('crypto')
 const os = require('os')
 const sourcemap = require('source-map')
+const assert = require('assert')
 
 require('tap').mochaGlobals()
 require('should')
@@ -88,6 +89,36 @@ ${'//'}${'#'} sourceMappingURL=data:application/json;base64,${base64Sourcemap}
       // that means it was bale to access the content via the provided sources object
       v8ToIstanbul.sourceTranspiled.should.not.be.undefined()
     })
+
+    it('should clamp line source column >= 0', async () => {
+      const v8ToIstanbul = new V8ToIstanbul(
+        `file://${require.resolve('./fixtures/scripts/needs-compile.compiled.js')}`,
+        0
+      )
+
+      // read the file and find the first end of line char
+      const fileBody = readFileSync(require.resolve('./fixtures/scripts/needs-compile.compiled.js')).toString()
+      const matchedNewLineChar = fileBody.match(/(?<=\r?\n)/u).index
+
+      // this isn't an assertion for the test so much as it is an assertion that the
+      // test fixture hasn't be reverted from \r\n to \n.
+      assert(fileBody.substring(matchedNewLineChar - 2, matchedNewLineChar) === '\r\n', 'The test fixture is misconfigured!')
+
+      await v8ToIstanbul.load()
+      // apply a fake range that starts with the matched new line
+      // (these ranges can occur on v8 running on windows) and verify
+      // coverage is applied correctly. CovLine will have a
+      // gap between the endCol of the previous line ending on \r and startCol of the
+      // next line. This would cause -1 to be sent for the source map lookup.
+      // This would cause source map translation to throw
+      v8ToIstanbul.applyCoverage([{
+        functionName: 'fake',
+        ranges: [{
+          startOffset: matchedNewLineChar - 1,
+          endOffset: matchedNewLineChar + 10
+        }]
+      }])
+    })
   })
   describe('source map format edge cases', () => {
     let consoleWarn