Issue 9271 - Forwarding lambda predicate with type inference causes segfault

[9rnsr]

https://d.puremagic.com/issues/show_bug.cgi?id=9271

Root cause is in the wrong mangling scheme for nested templates.

Currently, if TemplateInstance::enclosing != NULL, enclosing is preferentially used for the parent of mangled name.
However, if same name templates are instantiated with same nested arguments, their mangled name will conflict.

It can be checked by using dmd debug print at the end of FuncDeclaration::semantic3.

Current:

-FuncDeclaration::semantic3('any!(__lambda1, string[]).any', sc = 003D92A0, loc = imports\test9271a.d(3))
        mangle() = _D8test92714mainFZv30__T3anyS14main9__lambda1TAAyaZ3anyMFNaNbNfAAyaZb**
-FuncDeclaration::semantic3('any!((e) => e == "asd", string[]).any', sc = 003D8100, loc = test9271.d(5))
        mangle() = _D8test92714mainFZv30__T3anyS14main9__lambda1TAAyaZ3anyMFNaNbNfAAyaZb

After merging this PR, they will be fixed to:

-FuncDeclaration::semantic3('any!(__lambda1, string[]).any', sc = 01B192A0, loc = imports\test9271a.d(3))
        mangle() = _D7imports9test9271a3any30__T3anyS14main9__lambda1TAAyaZ3anyMFNaNbNfAAyaZb
-FuncDeclaration::semantic3('any!((e) => e == "asd", string[]).any', sc = 01B18100, loc = test9271.d(5))
        mangle() = _D8test92713any30__T3anyS14main9__lambda1TAAyaZ3anyMFNaNbNfAAyaZb

[9rnsr]

Note that, enclosing scope is implicitly mangled in the TemplateInstance arguments:

eg. _D8test92713any30__T3anyS14main9__lambda1TAAyaZ3anyMFNaNbNfAAyaZb

So any information won't be lost by this change.

[braddr]

Auto-merge toggled on

[braddr]

Auto-merge toggled off

[braddr]

Auto-merge toggled on

[braddr]

Auto-merge toggled off

[9rnsr]

Fix failures in test/runnable/nested.d and test/compilable/testInference.d.

[WalterBright]

Auto-merge toggled on