Improve the attempted dynamic environment-capture error message

src/librustc/middle/kind.rs

@@ -198,8 +198,9 @@ fn with_appropriate_checker(cx: Context, id: node_id,
     fn check_for_bare(cx: Context, fv: @freevar_entry) {
         cx.tcx.sess.span_err(
             fv.span,
-            "attempted dynamic environment capture");
-    }
+            "can't capture dynamic environment in a fn item; \
+            use the || { ... } closure form instead");
+    } // same check is done in resolve.rs, but shouldn't be done
 
     let fty = ty::node_id_to_type(cx.tcx, id);
     match ty::get(fty).sty {

src/librustc/middle/resolve.rs

@@ -3382,7 +3382,8 @@ impl Resolver {
 
                         self.session.span_err(
                             span,
-                            "attempted dynamic environment-capture");
+                            "can't capture dynamic environment in a fn item; \
+                            use the || { ... } closure form instead");
                     } else {
                         // This was an attempt to use a type parameter outside
                         // its scope.
@@ -3404,7 +3405,8 @@ impl Resolver {
 
                         self.session.span_err(
                             span,
-                            "attempted dynamic environment-capture");
+                            "can't capture dynamic environment in a fn item; \
+                            use the || { ... } closure form instead");
                     } else {
                         // This was an attempt to use a type parameter outside
                         // its scope.

src/test/compile-fail/bad-env-capture.rs

@@ -8,7 +8,7 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-// error-pattern: attempted dynamic environment-capture
+// error-pattern: can't capture dynamic environment in a fn item;
 fn foo() {
     let x: int;
     fn bar() { log(debug, x); }

src/test/compile-fail/bad-env-capture2.rs

@@ -8,7 +8,7 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-// error-pattern: attempted dynamic environment-capture
+// error-pattern: can't capture dynamic environment in a fn item;
 fn foo(x: int) {
     fn bar() { log(debug, x); }
 }

src/test/compile-fail/bad-env-capture3.rs

@@ -8,7 +8,7 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-// error-pattern: attempted dynamic environment-capture
+// error-pattern: can't capture dynamic environment in a fn item;
 fn foo(x: int) {
     fn mth() {
         fn bar() { log(debug, x); }

src/test/compile-fail/capture1.rs

@@ -10,7 +10,7 @@
 // except according to those terms.
 
 
-// error-pattern: attempted dynamic environment-capture
+// error-pattern: can't capture dynamic environment in a fn item;
 
 fn main() {
     let bar: int = 5;

src/test/compile-fail/issue-3021-b.rs

@@ -18,7 +18,7 @@ fn siphash(k0 : u64) {
 
     impl siphash {
         pub fn reset(&mut self) {
-           self.v0 = k0 ^ 0x736f6d6570736575; //~ ERROR attempted dynamic environment-capture
+           self.v0 = k0 ^ 0x736f6d6570736575; //~ ERROR can't capture dynamic environment
            //~^ ERROR unresolved name `k0`.
         }
     }

src/test/compile-fail/issue-3021-d.rs

@@ -30,9 +30,9 @@ fn siphash(k0 : u64, k1 : u64) -> siphash {
 
    impl siphash for SipState {
         fn reset(&self) {
-            self.v0 = k0 ^ 0x736f6d6570736575;  //~ ERROR attempted dynamic environment-capture
+            self.v0 = k0 ^ 0x736f6d6570736575; //~ ERROR can't capture dynamic environment
             //~^ ERROR unresolved name `k0`.
-            self.v1 = k1 ^ 0x646f72616e646f6d;   //~ ERROR attempted dynamic environment-capture
+            self.v1 = k1 ^ 0x646f72616e646f6d; //~ ERROR can't capture dynamic environment
             //~^ ERROR unresolved name `k1`.
         }
         fn result(&self) -> u64 { return mk_result(self); }

src/test/compile-fail/issue-3021.rs

@@ -21,7 +21,7 @@ fn siphash(k0 : u64) -> SipHash {
 
     impl SipHash for SipState {
         fn reset(&self) {
-           self.v0 = k0 ^ 0x736f6d6570736575; //~ ERROR attempted dynamic environment-capture
+           self.v0 = k0 ^ 0x736f6d6570736575; //~ ERROR can't capture dynamic environment
            //~^ ERROR unresolved name `k0`.
         }
     }