This code was trying to answer question: "Was this method overriden by something else in a more derived class"? It was walking the base hierarchy in canonical form, but that was leading to methods not resolving at all. The fix is to walk the non-canonical hierarchy and canonicalize after we resolved everything.

I ran into this in dotnet#108379 that unlocked more whole program devirtualization and `StringSearchValuesBase` is in this shape.

This code was trying to answer question: "Was this method overriden by something else in a more derived class"? It was walking the base hierarchy in canonical form, but that was leading to methods not resolving at all. The fix is to walk the non-canonical hierarchy and canonicalize after we resolved everything.

I ran into this in #108379 that unlocked more whole program devirtualization and `StringSearchValuesBase` is in this shape.

This code was trying to answer question: "Was this method overriden by something else in a more derived class"? It was walking the base hierarchy in canonical form, but that was leading to methods not resolving at all. The fix is to walk the non-canonical hierarchy and canonicalize after we resolved everything.

I ran into this in dotnet#108379 that unlocked more whole program devirtualization and `StringSearchValuesBase` is in this shape.

…tnet#108379)

We avoid devirtualizing into abstract classes because whole program view might have optimized away the method bodies and devirtualizing them doesn't lead to anything good.

However, if the whole program view had a non-abstract child of this, we can no longer optimize this out and devirtualization should be fine.

Fixes issue encountered in dotnet#108153 (comment)

…108470)

This code was trying to answer question: "Was this method overriden by something else in a more derived class"? It was walking the base hierarchy in canonical form, but that was leading to methods not resolving at all. The fix is to walk the non-canonical hierarchy and canonicalize after we resolved everything.

I ran into this in #108379 that unlocked more whole program devirtualization and `StringSearchValuesBase` is in this shape.

Co-authored-by: Jeff Schwartz <jeffschw@microsoft.com>

This code was trying to answer question: "Was this method overriden by something else in a more derived class"? It was walking the base hierarchy in canonical form, but that was leading to methods not resolving at all. The fix is to walk the non-canonical hierarchy and canonicalize after we resolved everything.

I ran into this in dotnet#108379 that unlocked more whole program devirtualization and `StringSearchValuesBase` is in this shape.

…tnet#108379)

We avoid devirtualizing into abstract classes because whole program view might have optimized away the method bodies and devirtualizing them doesn't lead to anything good.

However, if the whole program view had a non-abstract child of this, we can no longer optimize this out and devirtualization should be fine.

Fixes issue encountered in dotnet#108153 (comment)