================
@@ -0,0 +1,105 @@
+// RUN: %clang_cc1 -verify=expected,c-expected -std=c2y -Wall -pedantic %s
+// RUN: %clang_cc1 -verify=expected,c-expected,ped -std=c23 -Wall -pedantic %s
+// RUN: %clang_cc1 -verify=expected,cxx-expected,gnu -Wall -pedantic -x c++ %s
+// RUN: %clang_cc1 -verify=expected,c-expected,pre -std=c2y -Wpre-c2y-compat
-Wall -pedantic %s
+
+/* WG14 N3370: Yes
+ * Case range expressions v3.1
+ *
+ * This introduces the ability to specify closed ranges in case statements in a
+ * switch statement. This was already a well-supported Clang extension before
+ * it was standardized.
+ */
+
+void correct(int i) {
+ constexpr int j = 100, k = 200;
+ switch (i) {
+ case 12 ... 14: break; /* gnu-warning {{case ranges are a GNU extension}}
+ ped-warning {{case ranges are a C2y extension}}
+ pre-warning {{case ranges are incompatible with C
standards before C2y}}
+ */
+ // Implementations are encouraged to diagnose empty ranges.
+ case 15 ... 11: break; /* expected-warning {{empty case range specified}}
+ gnu-warning {{case ranges are a GNU extension}}
+ ped-warning {{case ranges are a C2y extension}}
+ pre-warning {{case ranges are incompatible with C
standards before C2y}}
+ */
+ // This is not an empty range, it's a range of a single value.
+ case 10 ... 10: break; /* gnu-warning {{case ranges are a GNU extension}}
+ ped-warning {{case ranges are a C2y extension}}
+ pre-warning {{case ranges are incompatible with C
standards before C2y}}
+ */
+ case j ... k: break; /* gnu-warning {{case ranges are a GNU extension}}
+ ped-warning {{case ranges are a C2y extension}}
+ pre-warning {{case ranges are incompatible with C
standards before C2y}}
+ */
+ }
+}
+
+void incorrect(int i) { // cxx-expected-note 2 {{declared here}}
+ switch (i) {
+ // The values have to be integer constant expressions. Note that when the
+ // initial value in the range is an error, we don't issue the warnings about
+ // extensions or incompatibility.
+ case i ... 10: break; /* c-expected-error {{expression is not an integer
constant expression}}
+ cxx-expected-error {{case value is not a
constant expression}}
+ cxx-expected-note {{function parameter 'i' with
unknown value cannot be used in a constant expression}}
+ */
+ case 10 ... i: break; /* c-expected-error {{expression is not an integer
constant expression}}
+ cxx-expected-error {{case value is not a
constant expression}}
+ cxx-expected-note {{function parameter 'i' with
unknown value cannot be used in a constant expression}}
+ gnu-warning {{case ranges are a GNU extension}}
+ ped-warning {{case ranges are a C2y extension}}
+ pre-warning {{case ranges are incompatible with
C standards before C2y}}
+ */
+ case 1.3f ... 10: break; /* c-expected-error {{integer constant expression
must have integer type, not 'float'}}
+ cxx-expected-error {{conversion from 'float' to
'int' is not allowed in a converted constant expression}}
+ */
+ case 10 ... "a": break; /* c-expected-error {{integer constant expression
must have integer type, not 'char[2]'}}
+ cxx-expected-error {{value of type 'const
char[2]' is not implicitly convertible to 'int'}}
+ gnu-warning {{case ranges are a GNU extension}}
+ ped-warning {{case ranges are a C2y extension}}
+ pre-warning {{case ranges are incompatible with
C standards before C2y}}
+ */
+ }
+
+ switch (i) {
+ // Cannot have multiple cases covering the same value.
+ // FIXME: diagnostic quality here is poor. The "previous case" note is
+ // showing up on a subsequent line (I'd expect the error and note to be
+ // reversed), and "duplicate case value 20" is showing up on a line where
+ // there is no duplicate value 20 to begin with.
+ case 10 ... 20: break; /* expected-error {{duplicate case value '11'}}
+ expected-note {{previous case defined here}}
+ gnu-warning {{case ranges are a GNU extension}}
+ ped-warning {{case ranges are a C2y extension}}
+ pre-warning {{case ranges are incompatible with C
standards before C2y}}
+ */
+ case 11: break; /* expected-note {{previous case defined here}}
+ */
+ case 11 ... 14: break; /* expected-error {{duplicate case value '20'}}
----------------
erichkeane wrote:
Oh my :)
https://github.com/llvm/llvm-project/pull/115054
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