[ASTUnit] Fix a regression in cached completions

[ilya-biryukov]

Summary

After r345152 cached completions started adding namespaces after
nested name specifiers, e.g. in some_name::^

The CCC_Symbol indicates the completed item cannot be a namespace (it is
described as being "a type, a function or a variable" in the comments).

Therefore, 'nested specifier' completions should only be added from cache
when the context is CCC_SymbolOrNewName (which roughly seems to indicate
that a nested name specifier is allowed).

Fixes https://bugs.llvm.org/show_bug.cgi?id=42646

[sammccall]

clang/test/Index/complete-qualified-with-preamble.cpp

7 ↗

(On Diff #210548)

Nit: This (and the filename) seems like a nonstandard use of "preamble" - is there precedent for this in ASTUnit?

Else maybe these are just "cached global completions" or something

[kadircet]

LGTM from my side as well

[ilya-biryukov]

• s/preamble/cached completions (in tests)

clang/test/Index/complete-qualified-with-preamble.cpp

7 ↗

(On Diff #210548)

Good point, this is focused on cached completions, not preambles. Renamed the file and update the comments.

There seem to be other tests mentioning preamble in test/Index. Though I'm not sure myself CINDEXTEST_EDITING=1 affects only whether preambles are being used, my knowledge here is definitely not very deep.

[sammccall]

clang/test/Index/complete-qualified-with-preamble.cpp

7 ↗

(On Diff #210548)

Thanks for the rename.

Looking at the implementation, CINDEXTEST_EDITING enables both preambles and completion caching, but they're separate features.

cfe/trunk/lib/Frontend/ASTUnit.cpp

case Result::RK_Declaration: {
           | (1LL << CodeCompletionContext::CCC_ClassStructUnion)
           | (1LL << CodeCompletionContext::CCC_Statement)
           | (1LL << CodeCompletionContext::CCC_Expression)
           | (1LL << CodeCompletionContext::CCC_ObjCMessageReceiver)
           | (1LL << CodeCompletionContext::CCC_EnumTag)
           | (1LL << CodeCompletionContext::CCC_UnionTag)
           | (1LL << CodeCompletionContext::CCC_ClassOrStructTag)
           | (1LL << CodeCompletionContext::CCC_Type)
-          | (1LL << CodeCompletionContext::CCC_Symbol)
           | (1LL << CodeCompletionContext::CCC_SymbolOrNewName)
           | (1LL << CodeCompletionContext::CCC_ParenthesizedExpression);
 
         if (isa<NamespaceDecl>(R.Declaration) ||
             isa<NamespaceAliasDecl>(R.Declaration))
           NNSContexts |= (1LL << CodeCompletionContext::CCC_Namespace);
 
         if (uint64_t RemainingContexts

cfe/trunk/test/Index/complete-qualified-cached.cpp

+namespace a_namespace {};
+class Class { static void foo(); };
+Class::
+// Completion for a_namespace should be available at the start of the line.
+// START-OF-LINE: a_namespace
+// START-OF-LINE: Class
+// -- Using cached completions.
+// RUN: CINDEXTEST_EDITING=1 c-index-test -code-completion-at=%s:3:1 %s \
+// RUN: | FileCheck --check-prefix=START-OF-LINE %s
+// -- Without cached completions.
+// RUN: c-index-test -code-completion-at=%s:3:1 %s \
+// RUN: | FileCheck --check-prefix=START-OF-LINE %s
+//
+//
+// ... and should not be available after 'Class::^'
+// AFTER-QUALIFIER: Class
+// -- Using cached completions.
+// RUN: CINDEXTEST_EDITING=1 c-index-test -code-completion-at=%s:3:8 %s \
+// RUN: | FileCheck --implicit-check-not=a_namespace --check-prefix=AFTER-QUALIFIER %s
+// -- Without cached completions.
+// RUN: c-index-test -code-completion-at=%s:3:8 %s \
+// RUN: | FileCheck --implicit-check-not=a_namespace --check-prefix=AFTER-QUALIFIER %s