Bug 1297706 - Fix FunctionBox::setStart to get the correct line/column. r=njn

js/src/frontend/SharedContext.h

@@ -582,8 +582,7 @@ class FunctionBox : public ObjectBox, public SharedContext
 
     void setStart(const TokenStream& tokenStream) {
         bufStart = tokenStream.currentToken().pos.begin;
-        startLine = tokenStream.getLineno();
-        startColumn = tokenStream.getColumn();
+        tokenStream.srcCoords.lineNumAndColumnIndex(bufStart, &startLine, &startColumn);
     }
 
     void trace(JSTracer* trc) override;

js/src/frontend/TokenStream.h

@@ -333,8 +333,6 @@ class MOZ_STACK_CLASS TokenStream
     }
     const CharBuffer& getTokenbuf() const { return tokenbuf; }
     const char* getFilename() const { return filename; }
-    unsigned getLineno() const { return lineno; }
-    unsigned getColumn() const { return userbuf.offset() - linebase - 1; }
     bool getMutedErrors() const { return mutedErrors; }
     JSVersion versionNumber() const { return VersionNumber(options().version); }
     JSVersion versionWithFlags() const { return options().version; }

js/src/jit-test/tests/arrow-functions/column-number.js

@@ -0,0 +1,6 @@
+function f() { return g(abcd => Error()); }
+function g(x) { return x(); }
+var err = f(1, 2);
+var lines = err.stack.split("\n");
+assertEq(lines[0].endsWith(":1:33"), true);
+assertEq(lines[1].endsWith(":2:24"), true);