This unifies our API naming convention. When standard is in the name
then we are using the netstandard2.0 API set and when it is not then it
is the simple desktop mscorlib46.

Both variants are necessary for CompileAndVerify style functions because
many of our tests that use it can only run on desktop or simply need to
have some of the netstandard2.0 API set missing.

MemberSemanticModel.GetBoundLambdaOrQuery should use GetAdjustedNodePosition helper to ensure proper handling of zero-length tokens at the beginning of a syntax node. (#24049)

Fixes #23883.

* Rename Foo to Goo

* Rename ifoo to igoo

* Add back BOMs

Narrow location in diagnostics for lambda symbol to either the delegate keyword or the arrow (#16990)

Fixes https://devdiv.visualstudio.com/DevDiv/_workitems?id=296550.

Fixes #15555
Checking in on behalf of @gafter 

Also added some checks that should help to figure out how to reproduce the crash.

The bug is that, as an optimization, we use 'null' as the delegate type for
a parameterless `delegate` lambda, but code elsewhere in the compiler
assumes that a null delegate type occurs only in error recovery situations.
Fixes #13797

We attempt to bind lambda args against every applicable delegate
type that could be a matching parameter, and then select the
"best" for error recovery.
This also has the effect of removing unbound lambdas from the
bound trees, replacing them with the "best" binding for error
recovery. This makes the semantic model insensitive to any further
trial bindings (i.e. mutation of the unbound lambda cache).
Fixes #12063, #11979, #11901

Remove vestigal "extensionMethodsOfSameViabilityAreAvailable"
thereby reducing coupling between internal compiler APIs.
See also #7740 #5128, where the vestigal APIs were introduced.

While working on another change I noticed that our testing support for experimental features didn't actually verify the underlying feature was experimental.  Hence helpers like ParseExperimental(...) would continue to function without error when tuples / ref returns were attached to the /langver switch.  This creates maintenance issues in our test framework as it's unclear what we're actually testing.

I refactored the code involved to verify the features are actually experimental and removed some troublesome helpers.

Fixes #557, #5498

because there are arguments missing, to force lambda binding
for error recovery.
Fixes #11053, #11358

to ensure that we bind the lambda for intellisense purposes.
I also hand-tested the scenario of #4480 to reproduce it on VS2015
and to verify that the problem does not occur on the master branch.
Fixes #4480

Also reduce cascaded diagnostics in lambdas inside queries.
Fixes #1867

Fixes #1867

It is unexpected to have parameters originated from source having empty names in correct programs.
Fixes #4527.

Fixes #5363.

All assignments in an expression tree should be an error.  Self
assignment was being flagged as only a warning which lead to later
errors in code generation.  Changed the behavior to warn and error for
self assignment (matches native compiler behavior).

close #3826

Fell out of our normal cadence for this during the push for RTM. Now that we
had a bit more breathing room getting us back on track here.

Addresses DevDiv 1179899.

Give an error when a type argument is inferred as void, and when a return statement has a void expression.
Fixes #1830

     Background:

     As discussed in the dev team all hands all code under the GitHub dotnet foundation is using a single process for contribution, API review, infrastructure and coding style. The idea is to present a unified view to our customer and give them a single story for contributing to any project under the dotnet foundation.

     https://github.com/dotnet/corefx/wiki/Contributing#c-coding-style

     The coding style transition is automated using a Roslyn based rewrite tool:

     https://github.com/dotnet/codeformatter

     This will be applied in stages across our developer tree. Right now the focus is on the Open directory as this is what is being presented on github. Code owners will be contacted before the transition happens.

     Note: this is a soft style requirement. There are no build errors that come from this change.
 (changeset 1408227)

The C# compiler was not using the correct syntax node to verify whether or not the expression body of an expression-bodied lambda or member was classified as a statement expression. This caused code to unexpectedly succeed to compile in certain cases (e.g. when the expression body was a parenthesized-expression that wrapped a valid statement expression), which broke conversions to void-returning delegates (and thus overload resolution, as in the original repro). This change adjusts the check to use the correct syntax node.
***NO_CI***
 (changeset 1406995)