Corrected a bug that could cause the source map info for a qualified name reference to point to the location of the qname's definition instead of the location of the reference itself.
Define a new DiagnosticType ILLEGAL_PROPERTY_CREATION_ON_UNION_TYPE that can be suppressed using strictMissingProperties.
Modify Closure Compiler open source build to pull in org.jspecify to add @Nullable annotations.
Remove support for @hidden as a part of message translation.
Always gather source map information for stages 1 and 2.
It doesn't make sense to specify the output source map location for the early stage invocations of a multi-stage build, but leaving it unspecified caused the compiler to lose type information that should have been gathered in those stages.