Issue 1:
Hello,

After updating from 1.0.3 to 1.0.4, my code is not anymore working. I getting the follwing error:

thread 'main' panicked at 'already borrowed: BorrowMutError', /rustc/4fb7144ed159f94491249e86d5bbd033b5d60550/src/libcore/cell.rs:878:9
stack backtrace:
0: backtrace::backtrace::libunwind::trace
at /cargo/registry/src/github.com-1ecc6299db9ec823/backtrace-0.3.44/src/backtrace/libunwind.rs:86
1: backtrace::backtrace::trace_unsynchronized
at /cargo/registry/src/github.com-1ecc6299db9ec823/backtrace-0.3.44/src/backtrace/mod.rs:66
2: std::sys_common::backtrace::_print_fmt
at src/libstd/sys_common/backtrace.rs:78
3: <std::sys_common::backtrace::_print::DisplayBacktrace as core::fmt::Display>::fmt
at src/libstd/sys_common/backtrace.rs:59
4: core::fmt::write
at src/libcore/fmt/mod.rs:1063
5: std::io::Write::write_fmt
at src/libstd/io/mod.rs:1426
6: std::sys_common::backtrace::_print
at src/libstd/sys_common/backtrace.rs:62
7: std::sys_common::backtrace::print
at src/libstd/sys_common/backtrace.rs:49
8: std::panicking::default_hook::{{closure}}
at src/libstd/panicking.rs:204
9: std::panicking::default_hook
at src/libstd/panicking.rs:224
10: std::panicking::rust_panic_with_hook
at src/libstd/panicking.rs:470
11: rust_begin_unwind
at src/libstd/panicking.rs:378
12: core::panicking::panic_fmt
at src/libcore/panicking.rs:85
13: core::option::expect_none_failed
at src/libcore/option.rs:1211
14: deno_core::bindings::send
15: <extern "C" fn(A0) .> R as rusty_v8::support::CFnFrom<F>>::mapping::c_fn
16: _ZN2v88internal25FunctionCallbackArguments4CallENS0_15CallHandlerInfoE
17: _ZN2v88internal12_GLOBAL__N_119HandleApiCallHelperILb0EEENS0_11MaybeHandleINS0_6ObjectEEEPNS0_7IsolateENS0_6HandleINS0_10HeapObjectEEESA_NS8_INS0_20FunctionTemplateInfoEEENS8_IS4_EENS0_16BuiltinArgumentsE
18: _ZN2v88internalL26Builtin_Impl_HandleApiCallENS0_16BuiltinArgumentsEPNS0_7IsolateE
19: Builtins_CEntry_Return1_DontSaveFPRegs_ArgvOnStack_BuiltinExit
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.
fatal runtime error: failed to initiate panic, error 5
Aborted (core dumped)

To reproduce, you can clone https://github.com/apiel/adka and run RUST_BACKTRACE=1 deno run -c tsconfig.json --allow-read --allow-write --allow-env --allow-net --unstable adka.ts. I suspect the dynamic import to be the cause of the problem in the main file: https://github.com/apiel/adka/blob/master/adka.ts#L19

Issue 2:
Received this error. For some additional info, I am only using the std/path module and some function from the Deno global.

thread 'main' panicked at 'already borrowed: BorrowMutError', /rustc/4fb7144ed159f94491249e86d5bbd033b5d60550/src/libcore/cell.rs:878:9
stack backtrace:
0: backtrace::backtrace::libunwind::trace
at /cargo/registry/src/github.com-1ecc6299db9ec823/backtrace-0.3.44/src/backtrace/libunwind.rs:86
1: backtrace::backtrace::trace_unsynchronized
at /cargo/registry/src/github.com-1ecc6299db9ec823/backtrace-0.3.44/src/backtrace/mod.rs:66
2: std::sys_common::backtrace::_print_fmt
at src/libstd/sys_common/backtrace.rs:78
3: <std::sys_common::backtrace::_print::DisplayBacktrace as core::fmt::Display>::fmt
at src/libstd/sys_common/backtrace.rs:59
4: core::fmt::write
at src/libcore/fmt/mod.rs:1063
5: std::io::Write::write_fmt
at src/libstd/io/mod.rs:1426
6: std::sys_common::backtrace::_print
at src/libstd/sys_common/backtrace.rs:62
7: std::sys_common::backtrace::print
at src/libstd/sys_common/backtrace.rs:49
8: std::panicking::default_hook::{{closure}}
at src/libstd/panicking.rs:204
9: std::panicking::default_hook
at src/libstd/panicking.rs:224
10: std::panicking::rust_panic_with_hook
at src/libstd/panicking.rs:470
11: rust_begin_unwind
at src/libstd/panicking.rs:378
12: core::panicking::panic_fmt
at src/libcore/panicking.rs:85
13: core::option::expect_none_failed
at src/libcore/option.rs:1211
14: deno_core::bindings::send
15: <extern "C" fn(A0) .> R as rusty_v8::support::CFnFrom<F>>::mapping::c_fn
16: _ZN2v88internal25FunctionCallbackArguments4CallENS0_15CallHandlerInfoE
17: _ZN2v88internal12_GLOBAL__N_119HandleApiCallHelperILb0EEENS0_11MaybeHandleINS0_6ObjectEEEPNS0_7IsolateENS0_6HandleINS0_10HeapObjectEEESA_NS8_INS0_20FunctionTemplateInfoEEENS8_IS4_EENS0_16BuiltinArgumentsE
18: _ZN2v88internalL26Builtin_Impl_HandleApiCallENS0_16BuiltinArgumentsEPNS0_7IsolateE
19: Builtins_CEntry_Return1_DontSaveFPRegs_ArgvOnStack_BuiltinExit
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.
fatal runtime error: failed to initiate panic, error 5
Aborted