cfg_version: pull out dedicated syntax test from feature gate test

The feature gate test was dual-purposing causing feature gate errors to
distract from syntax exercises.

tests/ui/cfg/cfg-version/syntax.rs

@@ -0,0 +1,152 @@
+//! Check `#[cfg(version(..))]` parsing.
+
+#![feature(cfg_version)]
+
+// Overall grammar
+// ===============
+//
+// `#[cfg(version(..))]` accepts only the `version(VERSION_STRING_LITERAL)` predicate form, where
+// only a single string literal is permitted.
+
+#[cfg(version(42))]
+//~^ ERROR expected a version literal
+fn not_a_string_literal_simple() {}
+
+#[cfg(version(1.20))]
+//~^ ERROR expected a version literal
+fn not_a_string_literal_semver_like() {}
+
+#[cfg(version(false))]
+//~^ ERROR expected a version literal
+fn not_a_string_literal_other() {}
+
+#[cfg(version("1.43", "1.44", "1.45"))]
+//~^ ERROR expected single version literal
+fn multiple_version_literals() {}
+
+// The key-value form `cfg(version = "..")` is not considered a valid `cfg(version(..))` usage, but
+// it will only trigger the `unexpected_cfgs` lint and not a hard error.
+
+#[cfg(version = "1.43")]
+//~^ WARN unexpected `cfg` condition name: `version`
+fn key_value_form() {}
+
+// Additional version string literal constraints
+// =============================================
+//
+// The `VERSION_STRING_LITERAL` ("version literal") has additional constraints on its syntactical
+// well-formedness.
+
+// 1. A valid version literal can only constitute of numbers and periods (a "simple" semver version
+// string). Non-semver strings or "complex" semver strings (such as build metadata) are not
+// considered valid version literals, and will emit a non-lint warning "unknown version literal
+// format".
+
+#[cfg(version("1.43.0"))]
+fn valid_major_minor_patch() {}
+
+#[cfg(version("0.0.0"))]
+fn valid_zero_zero_zero_major_minor_patch() {}
+
+#[cfg(version("foo"))]
+//~^ WARN unknown version literal format, assuming it refers to a future version
+fn not_numbers_or_periods() {}
+
+#[cfg(version("1.20.0-stable"))]
+//~^ WARN unknown version literal format, assuming it refers to a future version
+fn complex_semver_with_metadata() {}
+
+// 2. "Shortened" version strings are permitted but *only* for the omission of the patch number.
+
+#[cfg(version("1.0"))]
+fn valid_major_minor_1() {}
+
+#[cfg(version("1.43"))]
+fn valid_major_minor_2() {}
+
+#[cfg(not(version("1.44")))]
+fn valid_major_minor_negated_smoke_test() {}
+
+#[cfg(version("0.0"))]
+fn valid_zero_zero_major_minor() {}
+
+#[cfg(version("0.7"))]
+fn valid_zero_major_minor() {}
+
+// 3. Major-only, or other non-Semver-like strings are not permitted.
+
+#[cfg(version("1"))]
+//~^ WARN unknown version literal format, assuming it refers to a future version
+fn invalid_major_only() {}
+
+#[cfg(version("0"))]
+//~^ WARN unknown version literal format, assuming it refers to a future version
+fn invalid_major_only_zero() {}
+
+#[cfg(version(".7"))]
+//~^ WARN unknown version literal format, assuming it refers to a future version
+fn invalid_decimal_like() {}
+
+// Misc parsing overflow/underflow edge cases
+// ==========================================
+//
+// Check that we report "unknown version literal format" user-facing warnings and not ICEs.
+
+#[cfg(version("-1"))]
+//~^ WARN unknown version literal format, assuming it refers to a future version
+fn invalid_major_only_negative() {}
+
+// Implementation detail: we store rustc version as `{ major: u16, minor: u16, patch: u16 }`.
+
+#[cfg(version("65536"))]
+//~^ WARN unknown version literal format, assuming it refers to a future version
+fn exceed_u16_major() {}
+
+#[cfg(version("1.65536.0"))]
+//~^ WARN unknown version literal format, assuming it refers to a future version
+fn exceed_u16_minor() {}
+
+#[cfg(version("1.0.65536"))]
+//~^ WARN unknown version literal format, assuming it refers to a future version
+fn exceed_u16_patch() {}
+
+#[cfg(version("65536.0.65536"))]
+//~^ WARN unknown version literal format, assuming it refers to a future version
+fn exceed_u16_mixed() {}
+
+// Usage as `cfg!()`
+// =================
+
+fn cfg_usage() {
+    assert!(cfg!(version("1.0")));
+    assert!(cfg!(version("1.43")));
+    assert!(cfg!(version("1.43.0")));
+
+    assert!(cfg!(version("foo")));
+    //~^ WARN unknown version literal format, assuming it refers to a future version
+    assert!(cfg!(version("1.20.0-stable")));
+    //~^ WARN unknown version literal format, assuming it refers to a future version
+
+    assert!(cfg!(version = "1.43"));
+    //~^ WARN unexpected `cfg` condition name: `version`
+}
+
+fn main() {
+    cfg_usage();
+
+    // `cfg(version = "..")` is not a valid `cfg_version` form, but it only triggers
+    // `unexpected_cfgs` lint, and `cfg(version = "..")` eval to `false`.
+    key_value_form(); //~ ERROR cannot find function
+
+    // Invalid version literal formats within valid `cfg(version(..))` form should also cause
+    // `cfg(version(..))` eval to `false`.
+    not_numbers_or_periods(); //~ ERROR cannot find function
+    complex_semver_with_metadata(); //~ ERROR cannot find function
+    invalid_major_only(); //~ ERROR cannot find function
+    invalid_major_only_zero(); //~ ERROR cannot find function
+    invalid_major_only_negative(); //~ ERROR cannot find function
+    exceed_u16_major(); //~ ERROR cannot find function
+    exceed_u16_minor(); //~ ERROR cannot find function
+    exceed_u16_patch(); //~ ERROR cannot find function
+    exceed_u16_mixed(); //~ ERROR cannot find function
+}

tests/ui/cfg/cfg-version/syntax.stderr

@@ -0,0 +1,188 @@
+error: expected a version literal
+  --> $DIR/syntax.rs:11:15
+   |
+LL | #[cfg(version(42))]
+   |               ^^
+
+error: expected a version literal
+  --> $DIR/syntax.rs:15:15
+   |
+LL | #[cfg(version(1.20))]
+   |               ^^^^
+
+error: expected a version literal
+  --> $DIR/syntax.rs:19:15
+   |
+LL | #[cfg(version(false))]
+   |               ^^^^^
+
+error: expected single version literal
+  --> $DIR/syntax.rs:23:7
+   |
+LL | #[cfg(version("1.43", "1.44", "1.45"))]
+   |       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+warning: unknown version literal format, assuming it refers to a future version
+  --> $DIR/syntax.rs:51:15
+   |
+LL | #[cfg(version("foo"))]
+   |               ^^^^^
+
+warning: unknown version literal format, assuming it refers to a future version
+  --> $DIR/syntax.rs:55:15
+   |
+LL | #[cfg(version("1.20.0-stable"))]
+   |               ^^^^^^^^^^^^^^^
+
+warning: unknown version literal format, assuming it refers to a future version
+  --> $DIR/syntax.rs:78:15
+   |
+LL | #[cfg(version("1"))]
+   |               ^^^
+
+warning: unknown version literal format, assuming it refers to a future version
+  --> $DIR/syntax.rs:82:15
+   |
+LL | #[cfg(version("0"))]
+   |               ^^^
+
+warning: unknown version literal format, assuming it refers to a future version
+  --> $DIR/syntax.rs:86:15
+   |
+LL | #[cfg(version(".7"))]
+   |               ^^^^
+
+warning: unknown version literal format, assuming it refers to a future version
+  --> $DIR/syntax.rs:95:15
+   |
+LL | #[cfg(version("-1"))]
+   |               ^^^^
+
+warning: unknown version literal format, assuming it refers to a future version
+  --> $DIR/syntax.rs:101:15
+   |
+LL | #[cfg(version("65536"))]
+   |               ^^^^^^^
+
+warning: unknown version literal format, assuming it refers to a future version
+  --> $DIR/syntax.rs:105:15
+   |
+LL | #[cfg(version("1.65536.0"))]
+   |               ^^^^^^^^^^^
+
+warning: unknown version literal format, assuming it refers to a future version
+  --> $DIR/syntax.rs:109:15
+   |
+LL | #[cfg(version("1.0.65536"))]
+   |               ^^^^^^^^^^^
+
+warning: unknown version literal format, assuming it refers to a future version
+  --> $DIR/syntax.rs:113:15
+   |
+LL | #[cfg(version("65536.0.65536"))]
+   |               ^^^^^^^^^^^^^^^
+
+warning: unknown version literal format, assuming it refers to a future version
+  --> $DIR/syntax.rs:125:26
+   |
+LL |     assert!(cfg!(version("foo")));
+   |                          ^^^^^
+
+warning: unknown version literal format, assuming it refers to a future version
+  --> $DIR/syntax.rs:127:26
+   |
+LL |     assert!(cfg!(version("1.20.0-stable")));
+   |                          ^^^^^^^^^^^^^^^
+
+warning: unexpected `cfg` condition name: `version`
+  --> $DIR/syntax.rs:30:7
+   |
+LL | #[cfg(version = "1.43")]
+   |       ^^^^^^^^^^^^^^^^
+   |
+   = help: to expect this configuration use `--check-cfg=cfg(version, values("1.43"))`
+   = note: see <https://doc.rust-lang.org/nightly/rustc/check-cfg.html> for more information about checking conditional configuration
+   = note: `#[warn(unexpected_cfgs)]` on by default
+help: there is a similar config predicate: `version("..")`
+   |
+LL - #[cfg(version = "1.43")]
+LL + #[cfg(version("1.43"))]
+   |
+
+warning: unexpected `cfg` condition name: `version`
+  --> $DIR/syntax.rs:130:18
+   |
+LL |     assert!(cfg!(version = "1.43"));
+   |                  ^^^^^^^^^^^^^^^^
+   |
+   = help: to expect this configuration use `--check-cfg=cfg(version, values("1.43"))`
+   = note: see <https://doc.rust-lang.org/nightly/rustc/check-cfg.html> for more information about checking conditional configuration
+help: there is a similar config predicate: `version("..")`
+   |
+LL -     assert!(cfg!(version = "1.43"));
+LL +     assert!(cfg!(version("1.43")));
+   |
+
+error[E0425]: cannot find function `key_value_form` in this scope
+  --> $DIR/syntax.rs:139:5
+   |
+LL |     key_value_form();
+   |     ^^^^^^^^^^^^^^ not found in this scope
+
+error[E0425]: cannot find function `not_numbers_or_periods` in this scope
+  --> $DIR/syntax.rs:143:5
+   |
+LL |     not_numbers_or_periods();
+   |     ^^^^^^^^^^^^^^^^^^^^^^ not found in this scope
+
+error[E0425]: cannot find function `complex_semver_with_metadata` in this scope
+  --> $DIR/syntax.rs:144:5
+   |
+LL |     complex_semver_with_metadata();
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ not found in this scope
+
+error[E0425]: cannot find function `invalid_major_only` in this scope
+  --> $DIR/syntax.rs:145:5
+   |
+LL |     invalid_major_only();
+   |     ^^^^^^^^^^^^^^^^^^ not found in this scope
+
+error[E0425]: cannot find function `invalid_major_only_zero` in this scope
+  --> $DIR/syntax.rs:146:5
+   |
+LL |     invalid_major_only_zero();
+   |     ^^^^^^^^^^^^^^^^^^^^^^^ not found in this scope
+
+error[E0425]: cannot find function `invalid_major_only_negative` in this scope
+  --> $DIR/syntax.rs:147:5
+   |
+LL |     invalid_major_only_negative();
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^ not found in this scope
+
+error[E0425]: cannot find function `exceed_u16_major` in this scope
+  --> $DIR/syntax.rs:148:5
+   |
+LL |     exceed_u16_major();
+   |     ^^^^^^^^^^^^^^^^ not found in this scope
+
+error[E0425]: cannot find function `exceed_u16_minor` in this scope
+  --> $DIR/syntax.rs:149:5
+   |
+LL |     exceed_u16_minor();
+   |     ^^^^^^^^^^^^^^^^ not found in this scope
+
+error[E0425]: cannot find function `exceed_u16_patch` in this scope
+  --> $DIR/syntax.rs:150:5
+   |
+LL |     exceed_u16_patch();
+   |     ^^^^^^^^^^^^^^^^ not found in this scope
+
+error[E0425]: cannot find function `exceed_u16_mixed` in this scope
+  --> $DIR/syntax.rs:151:5
+   |
+LL |     exceed_u16_mixed();
+   |     ^^^^^^^^^^^^^^^^ not found in this scope
+
+error: aborting due to 14 previous errors; 14 warnings emitted
+
+For more information about this error, try `rustc --explain E0425`.

tests/ui/feature-gates/feature-gate-cfg-version.rs

@@ -1,49 +1,12 @@
-#[cfg(version(42))] //~ ERROR: expected a version literal
-//~^ ERROR `cfg(version)` is experimental and subject to change
-fn foo() {}
-#[cfg(version(1.20))] //~ ERROR: expected a version literal
-//~^ ERROR `cfg(version)` is experimental and subject to change
-fn foo() -> bool { true }
-#[cfg(version("1.44"))]
-//~^ ERROR `cfg(version)` is experimental and subject to change
-fn foo() -> bool { true }
-#[cfg(not(version("1.44")))]
-//~^ ERROR `cfg(version)` is experimental and subject to change
-fn foo() -> bool { false }
+//! Feature gate test for `cfg_version`.
+//!
+//! Tracking issue: #64796.
 
-#[cfg(version("1.43", "1.44", "1.45"))] //~ ERROR: expected single version literal
-//~^ ERROR `cfg(version)` is experimental and subject to change
-fn bar() -> bool  { false }
-#[cfg(version(false))] //~ ERROR: expected a version literal
-//~^ ERROR `cfg(version)` is experimental and subject to change
-fn bar() -> bool  { false }
-#[cfg(version("foo"))] //~ WARNING: unknown version literal format
-//~^ ERROR `cfg(version)` is experimental and subject to change
-fn bar() -> bool  { false }
-#[cfg(version("999"))] //~ WARNING: unknown version literal format
-//~^ ERROR `cfg(version)` is experimental and subject to change
-fn bar() -> bool  { false }
-#[cfg(version("-1"))] //~ WARNING: unknown version literal format
-//~^ ERROR `cfg(version)` is experimental and subject to change
-fn bar() -> bool  { false }
-#[cfg(version("65536"))] //~ WARNING: unknown version literal format
-//~^ ERROR `cfg(version)` is experimental and subject to change
-fn bar() -> bool  { false }
-#[cfg(version("0"))] //~ WARNING: unknown version literal format
-//~^ ERROR `cfg(version)` is experimental and subject to change
-fn bar() -> bool { true }
-#[cfg(version("1.0"))]
-//~^ ERROR `cfg(version)` is experimental and subject to change
-fn bar() -> bool { true }
-#[cfg(version("1.65536.2"))] //~ WARNING: unknown version literal format
-//~^ ERROR `cfg(version)` is experimental and subject to change
-fn bar() -> bool  { false }
-#[cfg(version("1.20.0-stable"))] //~ WARNING: unknown version literal format
+#[cfg(version("1.42"))]
 //~^ ERROR `cfg(version)` is experimental and subject to change
 fn bar() {}
 
 fn main() {
-    assert!(foo());
-    assert!(bar());
-    assert!(cfg!(version("1.42"))); //~ ERROR `cfg(version)` is experimental and subject to change
+    assert!(cfg!(version("1.42")));
+    //~^ ERROR `cfg(version)` is experimental and subject to change
 }