In gh-1134, I argued in favour of extending CopyExpr to use reflection
to handle all types, under the assumption that we missed many types.
I have now decided against that, for two reasons:

1. There weren't many unhandled types left
2. We cannot copy comments because of limitations in go/ast, and it
seems better to refuse generating suggested fixes than to swallow
comments. This is a general problem, but function literals are
particularly likely to contain comments.

Thus, we just add FuncType to the list of types we cannot copy. The
effect is that several checks in the quickfix package will not generate
suggested fixes in some cases.

Closes gh-1134

(cherry picked from commit 8af8898)

Closes gh-1202

(cherry picked from commit 4a64968)

…turn untyped nil

Closes gh-1242

(cherry picked from commit e88e689)

(cherry picked from commit 98c3eca)

(cherry picked from commit 273d35f)

We were storing absolute paths and full token.Position in the binary
output. This works fine when merging multiple runs from the same OS, but
not so when dealing with multiple OSs, which have different path
separators and different absolute paths. We also have to zero out
token.Position.Offset to handle different newlines on different OSs.

(cherry picked from commit 87cceb1)

MergeIfAny leads to false positives if the loop condition is a stub in
some build configurations.

(cherry picked from commit 3d6c86f)

Make use of the new -merge feature

(cherry picked from commit 59d7a28)

(cherry picked from commit 5be6941)

(cherry picked from commit bc5bdcd)

Closes gh-1247

(cherry picked from commit 6dbb73d)

(cherry picked from commit 1cd2556)

(cherry picked from commit d694aad)

Updates gh-1256

(cherry picked from commit 311d97b)

Closes gh-1187

(cherry picked from commit 416f0a8)